@misc{GorskiJungLietal.2020, author = {Gorski, Mathias and Jung, Bettina and Li, Yong and Matias-Garcia, Pamela R. and Wuttke, Matthias and Coassin, Stefan and Thio, Chris H. L. and Kleber, Marcus E. and Winkler, Thomas W. and Wanner, Veronika and Chai, Jin-Fang and Chu, Audrey Y. and Cocca, Massimiliano and Feitosa, Mary F. and Ghasemi, Sahar and Hoppmann, Anselm and Horn, Katrin and Li, Man and Nutile, Teresa and Scholz, Markus and Sieber, Karsten B. and Teumer, Alexander and Tin, Adrienne and Wang, Judy and Tayo, Bamidele O. and Ahluwalia, Tarunveer S. and Almgren, Peter and Bakker, Stephan J. L. and Banas, Bernhard and Bansal, Nisha and Biggs, Mary L. and Boerwinkle, Eric and B{\"o}ttinger, Erwin and Brenner, Hermann and Carroll, Robert J. and Chalmers, John and Chee, Miao-Li and Chee, Miao-Ling and Cheng, Ching-Yu and Coresh, Josef and de Borst, Martin H. and Degenhardt, Frauke and Eckardt, Kai-Uwe and Endlich, Karlhans and Franke, Andre and Freitag-Wolf, Sandra and Gampawar, Piyush and Gansevoort, Ron T. and Ghanbari, Mohsen and Gieger, Christian and Hamet, Pavel and Ho, Kevin and Hofer, Edith and Holleczek, Bernd and Foo, Valencia Hui Xian and Hutri-Kahonen, Nina and Hwang, Shih-Jen and Ikram, M. Arfan and Josyula, Navya Shilpa and Kahonen, Mika and Khor, Chiea-Chuen and Koenig, Wolfgang and Kramer, Holly and Kraemer, Bernhard K. and Kuehnel, Brigitte and Lange, Leslie A. and Lehtimaki, Terho and Lieb, Wolfgang and Loos, Ruth J. F. and Lukas, Mary Ann and Lyytikainen, Leo-Pekka and Meisinger, Christa and Meitinger, Thomas and Melander, Olle and Milaneschi, Yuri and Mishra, Pashupati P. and Mononen, Nina and Mychaleckyj, Josyf C. and Nadkarni, Girish N. and Nauck, Matthias and Nikus, Kjell and Ning, Boting and Nolte, Ilja M. and O'Donoghue, Michelle L. and Orho-Melander, Marju and Pendergrass, Sarah A. and Penninx, Brenda W. J. H. and Preuss, Michael H. and Psaty, Bruce M. and Raffield, Laura M. and Raitakari, Olli T. and Rettig, Rainer and Rheinberger, Myriam and Rice, Kenneth M. and Rosenkranz, Alexander R. and Rossing, Peter and Rotter, Jerome and Sabanayagam, Charumathi and Schmidt, Helena and Schmidt, Reinhold and Schoettker, Ben and Schulz, Christina-Alexandra and Sedaghat, Sanaz and Shaffer, Christian M. and Strauch, Konstantin and Szymczak, Silke and Taylor, Kent D. and Tremblay, Johanne and Chaker, Layal and van der Harst, Pim and van der Most, Peter J. and Verweij, Niek and Voelker, Uwe and Waldenberger, Melanie and Wallentin, Lars and Waterworth, Dawn M. and White, Harvey D. and Wilson, James G. and Wong, Tien-Yin and Woodward, Mark and Yang, Qiong and Yasuda, Masayuki and Yerges-Armstrong, Laura M. and Zhang, Yan and Snieder, Harold and Wanner, Christoph and Boger, Carsten A. and Kottgen, Anna and Kronenberg, Florian and Pattaro, Cristian and Heid, Iris M.}, title = {Meta-analysis uncovers genome-wide significant variants for rapid kidney function decline}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Reihe der Digital Engineering Fakult{\"a}t}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Reihe der Digital Engineering Fakult{\"a}t}, number = {19}, doi = {10.25932/publishup-56537}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-565379}, pages = {14}, year = {2020}, abstract = {Rapid decline of glomerular filtration rate estimated from creatinine (eGFRcrea) is associated with severe clinical endpoints. In contrast to cross-sectionally assessed eGFRcrea, the genetic basis for rapid eGFRcrea decline is largely unknown. To help define this, we meta-analyzed 42 genome-wide association studies from the Chronic Kidney Diseases Genetics Consortium and United Kingdom Biobank to identify genetic loci for rapid eGFRcrea decline. Two definitions of eGFRcrea decline were used: 3 mL/min/1.73m(2)/year or more ("Rapid3"; encompassing 34,874 cases, 107,090 controls) and eGFRcrea decline 25\% or more and eGFRcrea under 60 mL/min/1.73m(2) at follow-up among those with eGFRcrea 60 mL/min/1.73m(2) or more at baseline ("CKDi25"; encompassing 19,901 cases, 175,244 controls). Seven independent variants were identified across six loci for Rapid3 and/or CKDi25: consisting of five variants at four loci with genome-wide significance (near UMOD-PDILT (2), PRKAG2, WDR72, OR2S2) and two variants among 265 known eGFRcrea variants (near GATM, LARP4B). All these loci were novel for Rapid3 and/or CKDi25 and our bioinformatic follow-up prioritized variants and genes underneath these loci. The OR2S2 locus is novel for any eGFRcrea trait including interesting candidates. For the five genome-wide significant lead variants, we found supporting effects for annual change in blood urea nitrogen or cystatin-based eGFR, but not for GATM or (LARP4B). Individuals at high compared to those at low genetic risk (8-14 vs. 0-5 adverse alleles) had a 1.20-fold increased risk of acute kidney injury (95\% confidence interval 1.08-1.33). Thus, our identified loci for rapid kidney function decline may help prioritize therapeutic targets and identify mechanisms and individuals at risk for sustained deterioration of kidney function.}, language = {en} } @article{GorskiJungLietal.2020, author = {Gorski, Mathias and Jung, Bettina and Li, Yong and Matias-Garcia, Pamela R. and Wuttke, Matthias and Coassin, Stefan and Thio, Chris H. L. and Kleber, Marcus E. and Winkler, Thomas W. and Wanner, Veronika and Chai, Jin-Fang and Chu, Audrey Y. and Cocca, Massimiliano and Feitosa, Mary F. and Ghasemi, Sahar and Hoppmann, Anselm and Horn, Katrin and Li, Man and Nutile, Teresa and Scholz, Markus and Sieber, Karsten B. and Teumer, Alexander and Tin, Adrienne and Wang, Judy and Tayo, Bamidele O. and Ahluwalia, Tarunveer S. and Almgren, Peter and Bakker, Stephan J. L. and Banas, Bernhard and Bansal, Nisha and Biggs, Mary L. and Boerwinkle, Eric and B{\"o}ttinger, Erwin and Brenner, Hermann and Carroll, Robert J. and Chalmers, John and Chee, Miao-Li and Chee, Miao-Ling and Cheng, Ching-Yu and Coresh, Josef and de Borst, Martin H. and Degenhardt, Frauke and Eckardt, Kai-Uwe and Endlich, Karlhans and Franke, Andre and Freitag-Wolf, Sandra and Gampawar, Piyush and Gansevoort, Ron T. and Ghanbari, Mohsen and Gieger, Christian and Hamet, Pavel and Ho, Kevin and Hofer, Edith and Holleczek, Bernd and Foo, Valencia Hui Xian and Hutri-Kahonen, Nina and Hwang, Shih-Jen and Ikram, M. Arfan and Josyula, Navya Shilpa and Kahonen, Mika and Khor, Chiea-Chuen and Koenig, Wolfgang and Kramer, Holly and Kraemer, Bernhard K. and Kuehnel, Brigitte and Lange, Leslie A. and Lehtimaki, Terho and Lieb, Wolfgang and Loos, Ruth J. F. and Lukas, Mary Ann and Lyytikainen, Leo-Pekka and Meisinger, Christa and Meitinger, Thomas and Melander, Olle and Milaneschi, Yuri and Mishra, Pashupati P. and Mononen, Nina and Mychaleckyj, Josyf C. and Nadkarni, Girish N. and Nauck, Matthias and Nikus, Kjell and Ning, Boting and Nolte, Ilja M. and O'Donoghue, Michelle L. and Orho-Melander, Marju and Pendergrass, Sarah A. and Penninx, Brenda W. J. H. and Preuss, Michael H. and Psaty, Bruce M. and Raffield, Laura M. and Raitakari, Olli T. and Rettig, Rainer and Rheinberger, Myriam and Rice, Kenneth M. and Rosenkranz, Alexander R. and Rossing, Peter and Rotter, Jerome and Sabanayagam, Charumathi and Schmidt, Helena and Schmidt, Reinhold and Schoettker, Ben and Schulz, Christina-Alexandra and Sedaghat, Sanaz and Shaffer, Christian M. and Strauch, Konstantin and Szymczak, Silke and Taylor, Kent D. and Tremblay, Johanne and Chaker, Layal and van der Harst, Pim and van der Most, Peter J. and Verweij, Niek and Voelker, Uwe and Waldenberger, Melanie and Wallentin, Lars and Waterworth, Dawn M. and White, Harvey D. and Wilson, James G. and Wong, Tien-Yin and Woodward, Mark and Yang, Qiong and Yasuda, Masayuki and Yerges-Armstrong, Laura M. and Zhang, Yan and Snieder, Harold and Wanner, Christoph and Boger, Carsten A. and Kottgen, Anna and Kronenberg, Florian and Pattaro, Cristian and Heid, Iris M.}, title = {Meta-analysis uncovers genome-wide significant variants for rapid kidney function decline}, series = {Kidney international : official journal of the International Society of Nephrology}, volume = {99}, journal = {Kidney international : official journal of the International Society of Nephrology}, number = {4}, publisher = {Elsevier}, address = {New York}, organization = {Lifelines Cohort Study
Regeneron Genetics Ctr}, issn = {0085-2538}, doi = {10.1016/j.kint.2020.09.030}, pages = {926 -- 939}, year = {2020}, abstract = {Rapid decline of glomerular filtration rate estimated from creatinine (eGFRcrea) is associated with severe clinical endpoints. In contrast to cross-sectionally assessed eGFRcrea, the genetic basis for rapid eGFRcrea decline is largely unknown. To help define this, we meta-analyzed 42 genome-wide association studies from the Chronic Kidney Diseases Genetics Consortium and United Kingdom Biobank to identify genetic loci for rapid eGFRcrea decline. Two definitions of eGFRcrea decline were used: 3 mL/min/1.73m(2)/year or more ("Rapid3"; encompassing 34,874 cases, 107,090 controls) and eGFRcrea decline 25\% or more and eGFRcrea under 60 mL/min/1.73m(2) at follow-up among those with eGFRcrea 60 mL/min/1.73m(2) or more at baseline ("CKDi25"; encompassing 19,901 cases, 175,244 controls). Seven independent variants were identified across six loci for Rapid3 and/or CKDi25: consisting of five variants at four loci with genome-wide significance (near UMOD-PDILT (2), PRKAG2, WDR72, OR2S2) and two variants among 265 known eGFRcrea variants (near GATM, LARP4B). All these loci were novel for Rapid3 and/or CKDi25 and our bioinformatic follow-up prioritized variants and genes underneath these loci. The OR2S2 locus is novel for any eGFRcrea trait including interesting candidates. For the five genome-wide significant lead variants, we found supporting effects for annual change in blood urea nitrogen or cystatin-based eGFR, but not for GATM or (LARP4B). Individuals at high compared to those at low genetic risk (8-14 vs. 0-5 adverse alleles) had a 1.20-fold increased risk of acute kidney injury (95\% confidence interval 1.08-1.33). Thus, our identified loci for rapid kidney function decline may help prioritize therapeutic targets and identify mechanisms and individuals at risk for sustained deterioration of kidney function.}, language = {en} } @article{HenschDahmRitteretal.2019, author = {Hensch, Martin and Dahm, Torsten and Ritter, Joachim and Heimann, Sebastian and Schmidt, Bernd and Stange, Stefan and Lehmann, Klaus}, title = {Deep low-frequency earthquakes reveal ongoing magmatic recharge beneath Laacher See Volcano (Eifel, Germany)}, series = {Geophysical journal international}, volume = {216}, journal = {Geophysical journal international}, number = {3}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0956-540X}, doi = {10.1093/gji/ggy532}, pages = {2025 -- 2036}, year = {2019}, abstract = {The occurrence of deep low-frequency (DLF) microearthquakes beneath volcanoes is commonly attributed to mass transport in the volcanic plumbing system and used to infer feeding channels from and into magma reservoirs. The key question is how magmas migrate from depth to the shallow crust and whether magma reservoirs are currently being recharged. For the first time since the improvement of the local seismic networks in the East Eifel region (Rhineland-Palatinate, Germany), we detect and locate recurrent DLF earthquakes in the lower crust and upper mantle beneath the Laacher See Volcano (LSV), using a joint data set of permanent sensors and a temporary deployment. So far, eight DLF earthquake sequences were observed in four distinct clusters between 10 and 40 km depth. These clusters of weak events (M-L< 2) align along an approximately 80. southeast dipping line south of the LSV. Moment tensor solutions of these events have large shear components, and the irregular dispersion and long coda of body waves indicate interaction processes between shear cracks and fluids. We find a rotation of P-axes orientation for shallow tectonic earthquakes compared to DLF events, indicating that the stress field in the depth interval of DLF events might favour a vertical migration of magma or magmatic fluids. The caldera of the LSV was formed by the last major eruption of the East Eifel Volcanic Field only 12.9 kyr ago, fed by a shallow magma chamber at 5-8 km depth and erupting a total magma volume of 6.7 km(3). The observed DLF earthquake activity and continuous volcanic gas emissions around the LSV indicate an active magmatic system, possibly connected with an upper mantle melt zone.}, language = {en} } @article{SchultzeSchmidt2019, author = {Schultze, Christiane and Schmidt, Bernd}, title = {Functionalized Benzofurans via Microwave-Promoted Tandem Claisen-Rearrangement/5-endo-dig Cyclization}, series = {Journal of heterocyclic chemistry}, volume = {56}, journal = {Journal of heterocyclic chemistry}, number = {9}, publisher = {Wiley}, address = {Hoboken}, issn = {0022-152X}, doi = {10.1002/jhet.3671}, pages = {2619 -- 2629}, year = {2019}, abstract = {Ortho-allyloxy alkinyl benzenes undergo, upon microwave irradiation in dimethylformamide, a tandem sequence of Claisen-rearrangement and 5-endo-dig cyclization to furnish 7-allyl-substituted benzofurans. With terminal alkynes, chroman-4-ones and enaminoketones become the main products. A mechanistic proposal for this observation relies on a reaction of the starting material with the solvent dimethylformamide under the microwave conditions.}, language = {en} } @article{SchmidtNave2006, author = {Schmidt, Bernd and Nave, Stefan}, title = {Stereoselective syntheses of enantiomerically pure 2,5-disubstituted dihydropyrans based on olefin metathesis}, series = {The journal of organic chemistry}, volume = {71}, journal = {The journal of organic chemistry}, number = {19}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo061190k}, pages = {7364 -- 7369}, year = {2006}, abstract = {A short synthesis of 2,5-disubstituted dihydropyrans starting from D-mannitol as a chiral building block is described. Our synthetic approach combines ruthenium-catalyzed ring closing olefin metathesis and palladium-catalyzed nucleophilic substitution.}, language = {en} } @article{PazHeydenreichSchmidtetal.2018, author = {Paz, Cristian and Heydenreich, Matthias and Schmidt, Bernd and Vadra, Nahir and Baggio, Ricardo}, title = {Three new dihydro-beta-agarofuran sesquiterpenes from the seeds of Maytenus boaria}, series = {Acta Crystallographica Section C}, volume = {74}, journal = {Acta Crystallographica Section C}, publisher = {International Union of Crystallography}, address = {Chester}, issn = {2053-2296}, doi = {10.1107/S2053229618005429}, pages = {564 -- 570}, year = {2018}, abstract = {As part of a project studying the secondary metabolites extracted from the Chilean flora, we report herein three new beta-agarofuran sesquiterpenes, namely (1S,4S,5S,6R,7R,8R,9R,10S)-6-acetoxy-4,9-dihydroxy-2,2,5a,9-tetramethyloctahydro-2H-3,9a-methanobenzo[b] oxepine-5,10-diylbis(furan-3-carboxylate), C27H32O11, (II), (1S,4S,5S,6R,7R,9S,10S)-6-acetoxy-9-hydroxy-2,2,5a, 9-tetramethyloctahydro-2H-3,9a-methanobenzo[ b] oxepine-5,10-diyl bis(furan-3-carboxylate), C27H32O10, (III), and (1S,4S,5S,6R,7R,9S,10S)-6-acetoxy-10-(benzoyloxy)-9-hydroxy-2,2,5a,9-tetramethyloctahydro-2H-3,9a-methanobenzo[b]oxepin-5-yl furan-3-carboxylate, C29H34O9, (IV), obtained from the seeds of Maytenus boaria and closely associated with a recently published relative [Paz et al. (2017). Acta Cryst. C73, 451-457]. In the (isomorphic) structures of (II) and (III), the central decalin system is esterified with an acetate group at site 1 and furoate groups at sites 6 and 9, and differ at site 8, with an OH group in (II) and no substituent in (III). This position is also unsubstituted in (IV), with site 6 being occupied by a benzoate group. The chirality of the skeletons is described as 1S, 4S, 5S, 6R, 7R, 8R, 9R, 10S in (II) and 1S, 4S, 5S, 6R, 7R, 9S, 10S in (III) and (IV), matching the chirality suggested by NMR studies. This difference in the chirality sequence among the title structures (in spite of the fact that the three skeletons are absolutely isostructural) is due to the differences in the environment of site 8, i.e. OH in (II) and H in (III) and (IV). This diversity in substitution, in turn, is responsible for the differences in the hydrogen-bonding schemes, which is discussed.}, language = {en} } @article{SchmidtSchultze2018, author = {Schmidt, Bernd and Schultze, Christiane}, title = {A one-pot synthesis of pyranocoumarins through microwave-promoted propargyl claisen rearrangement/wittig olefination}, series = {European journal of organic chemistry}, volume = {2018}, journal = {European journal of organic chemistry}, number = {2}, publisher = {Wiley-VCH Verl.}, address = {Weinheim}, issn = {1434-193X}, pages = {223 -- 227}, year = {2018}, abstract = {The reaction between propargyl ethers of hydroxybenzaldehydes and the ylide ethyl (triphenylphosphoranylidene)acetate was carried out under microwave irradiation to regioselectively afford angular pyranocoumarins. The chromene and coumarin heterocyclic scaffolds were simultaneously formed in the same synthetic step without changing the reaction conditions. The natural products seselin, braylin, and dipetalolactone were among the products synthesized by this method.}, language = {en} } @article{SchmidtPetersenBraun2018, author = {Schmidt, Bernd and Petersen, Monib H. and Braun, Diana}, title = {Bidirectional Synthesis of 6-Acetoxy-5-hexadecanolide, the Mosquito Oviposition Pheromone of Culex quinquefasciatus, from a C-2-Symmetric Building Block Using Olefin Metathesis Reactions}, series = {The journal of organic chemistry}, volume = {83}, journal = {The journal of organic chemistry}, number = {3}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.7b02944}, pages = {1627 -- 1633}, year = {2018}, abstract = {(5R,6S)-6-Acetoxy-5-hexadecanolide (MOP) is the oviposition pheromone of the mosquito Cx. quinquefasciatus, a vector of pathogens causing a variety of tropical diseases. We describe and evaluate herein three syntheses of MOP starting from mannitol-derived (3R,4R)-hexa-1,5-diene-3,4-diol. This C-2-symmetric building block is elaborated through bidirectional olefin metathesis reactions into 6-epi-MOP, which was converted into MOP via Mitsunobu inversion. The shortest of the three routes makes use of two sequential cross-metathesis reactions and an assisted tandem catalytic olefin reduction, induced by an in situ conversion of a Ru-carbene to a Ru-hydride.}, language = {en} } @article{SandSchmidt2021, author = {Sand, Patrick and Schmidt, Bernd}, title = {Pd-catalyzed oxidative sulfoalkenylation of acetanilides and traceless removal of the catalyst directing group}, series = {ChemistrySelect}, volume = {6}, journal = {ChemistrySelect}, number = {14}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {2365-6549}, doi = {10.1002/slct.202101009}, pages = {3563 -- 3567}, year = {2021}, abstract = {The palladium-catalyzed oxidative Heck-reaction, also referred to as Fujiwara-Moritani-reaction, has been investigated for the synthesis of styrenylsulfonyl compounds. Acetanilides and vinylsulfonyl compounds undergo dehydrogenative coupling reactions in moderate to quantitative yields, using benzoquinone as the oxidant of choice. Potassium peroxodisulfate, which had previously been identified as a superior oxidant for the coupling with acrylates, did not provide any coupling products with these olefins. Traceless removal of the catalyst directing group through a deacetylation-diazotation-coupling (DDC) sequence was demonstrated for 2-arylethene sulfones.}, language = {en} } @article{LoodSchmidt2020, author = {Lood, Kajsa and Schmidt, Bernd}, title = {Stereoselective synthesis of conjugated polyenes based on tethered olefin metathesis and carbonyl olefination}, series = {The journal of organic chemistry}, volume = {85}, journal = {The journal of organic chemistry}, number = {7}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.0c00446}, pages = {5122 -- 5130}, year = {2020}, abstract = {The combination of a highly stereoselective tethered olefin metathesis reaction and a Julia-Kocienski olefination is presented as a strategy for the synthesis of conjugated polyenes with at least one Z-configured C=C bond. The strategy is exemplified by the synthesis of the marine natural product (+)-bretonin B.}, language = {en} } @article{SchultzeFossSchmidt2020, author = {Schultze, Christiane and Foß, Stefan and Schmidt, Bernd}, title = {8-Prenylflavanones through microwave promoted tandem claisen rearrangement/6-endo-trig cyclization and cross metathesis}, series = {European journal of organic chemistry}, volume = {2020}, journal = {European journal of organic chemistry}, number = {47}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.202001378}, pages = {7373 -- 7384}, year = {2020}, abstract = {Prenylated flavanones were obtained from ortho-allyloxy chalcones through a one-pot sequence of Claisen rearrangement and 6-endo-trig cyclization, followed by olefin cross metathesis of the intermediate allyl flavanones with 2-methyl-2-butene. The synthetic utility of this route is illustrated for the synthesis of several naturally occurring prenyl flavanones.}, language = {en} } @article{LoodTikkKruegeretal.2022, author = {Lood, Kajsa and Tikk, Triin and Kr{\"u}ger, Mandy and Schmidt, Bernd}, title = {Methylene capping facilitates cross-metathesis reactions of enals}, series = {The journal of organic chemistry}, volume = {87}, journal = {The journal of organic chemistry}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c02851}, pages = {3079 -- 3088}, year = {2022}, abstract = {Four combinations of type-I olefins isoeugenol and 4-hydroxy-3-methoxystyrene with type-II olefins acrolein and crotonaldehyde were investigated in cross-metathesis (CM) reactions. While both type-I olefins are suitable CM partners for this transformation, we observed synthetically useful conversions only with type-II olefin crotonaldehyde. For economic reasons, isoeugenol, a cheap xylochemical available from renewable lignocellulose or from clove oil, is the preferred type-I CM partner. Nearly quantitative conversions to coniferyl aldehyde by the CM reaction of isoeugenol and crotonaldehyde can be obtained at ambient temperature without a solvent or at high substrate concentrations of 2 mol.L-1 with the second-generation Hoveyda-Grubbs catalyst. Under these conditions, the ratio of reactants can be reduced to 1:1.5 and catalyst loadings as low as 0.25 mol \% are possible. The high reactivity of the isoeugenol/crotonaldehyde combination in olefin metathesis reactions was demonstrated by a short synthesis of the natural product 7-methoxywutaifuranal, which was obtained from isoeugenol in a 44\% yield over five steps. We suggest that the superior performance of crotonaldehyde in the CM reactions investigated can be rationalized by "methylene capping", i.e., the steric stabilization of the propagating Ru-alkylidene species.}, language = {en} } @article{HermannsSchmidtGlowinskietal.2020, author = {Hermanns, Jolanda and Schmidt, Bernd and Glowinski, Ingrid and Keller, David}, title = {Online teaching in the course "organic chemistry" for nonmajor chemistry students}, series = {Journal of chemical education}, volume = {97}, journal = {Journal of chemical education}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {0021-9584}, doi = {10.1021/acs.jchemed.0c00658}, pages = {3140 -- 3146}, year = {2020}, abstract = {In this communication the development of an online course on the topic organic chemistry for nonmajor chemistry students is described and discussed. For this online course, the existing classroom course was further developed. New elements such as podcasts, task navigators, and a forum for discussing the solving of tasks or problems with the content were added. This new online course was evaluated. Therefore, a questionnaire was developed. This consists of questions with regard to the longtime learning behavior of the students and to the online learning. The results of this evaluation show that a preference for online learning and a preference for classroom teaching can be measured separately in two scales. Students values on the scale representing a preference for online learning correlate positively and significantly with confidence in the choice of the study subject, enthusiasm about the subject, and the ability to organize their learning, learning environment, and time management. They correlate also with the satisfaction concerning the materials provided. Students values for one of those teaching methods also correlate with their rating with regard to their exam preparation. Values representing a preference for online teaching correlate positively with students better feeling of exam preparation. Values representing a preference for classroom teaching show negative correlations with the values representing students similar or even better preparation for the exams as a result of online teaching. It is therefore not surprising that the ratings for the two scales correlate with the wish for a combination of online teaching and classroom teaching in the future. As a solution, a new course concept for the time after the corona virus crisis that suits all students is outlined in the outlook.}, language = {en} } @misc{SchmidtHauke2013, author = {Schmidt, Bernd and Hauke, Sylvia}, title = {Cross metathesis of allyl alcohols}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95037}, pages = {4194 -- 4206}, year = {2013}, abstract = {Under standard conditions the cross metathesis of allyl alcohols and methyl acrylate is accompanied by the formation of ketones, resulting from uncontrolled and undesired double bond isomerization. By conducting the CM in the presence of phenol, the catalyst loading and the reaction time required for quantiative conversion can be reduced, and isomerization can be suppressed. On the other hand, consecutive isomerization can be deliberately promoted by evaporating excess methyl acrylate after completing cross metathesis and by adding a base or silane as chemical triggers.}, language = {en} } @book{BuddrusSchmidt2015, author = {Buddrus, Joachim and Schmidt, Bernd}, title = {Grundlagen der organischen Chemie}, edition = {5., {\"u}berarb. und aktualisierte Aufl.}, publisher = {de Gruyter}, address = {Berlin}, isbn = {978-3-11-030559-3}, publisher = {Universit{\"a}t Potsdam}, pages = {946}, year = {2015}, language = {de} } @book{MetteCzechKlausetal.1994, author = {Mette, Dieter and Czech, Olaf and Klaus, Elisabeth and Meier, Bernd and Neumann, Karin and Schmeer, Ernst and Schmidt, Volkhard and Sachs, Conrad}, title = {Arbeitslehre aktuell : Schwerpunkt Technik, Bd. 1}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, isbn = {3-486-88725-4}, pages = {208 S.}, year = {1994}, language = {de} } @article{DamesZimmermannSchmidtetal.2006, author = {Dames, Petra and Zimmermann, Bernhard and Schmidt, Ruth and Rein, Julia and Voss, Martin and Schewe, Bettina and Walz, Bernd and Baumann, Otto}, title = {cAMP regulates plasma membrane vacuolar-type H+-ATPase assembly and activity in blowfly salivary glands}, issn = {0027-8424}, doi = {10.1073/pnas.0600011103}, year = {2006}, abstract = {Reversible assembly of the V0V1 holoenzyme from V-0 and V-1 subcomplexes is a widely used mechanism for regulation of vacuolar-type H+-ATPases (V-ATPases) in animal cells. in the blowfly (Calliphora vicina) salivary gland, V- ATPase is located in the apical membrane of the secretory cells and energizes the secretion of a KCl-rich saliva in response to the hormone serotonin. We have examined whether the CAMP pathway, known to be activated by serotonin, controls V-ATPase assembly and activity. Fluorescence measurements of pH changes at the luminal surface of isolated glands demonstrate that CAMP, Sp-adenosine-3',5'-cyclic monophosphorothioate, or forskolin, similar to serotonin, cause V-ATPase-dependent luminal acidification. In addition, V-ATPase-dependent ATP hydrolysis increases upon treatment with these agents. Immunofluorescence microscopy and pelleting assays have demonstrated further that V, components become translocated from the cytoplasm to the apical membrane and V-ATPase holoenzymes are assembled at the apical membrane during conditions that increase intracellular cAMP. Because these actions occur without a change in cytosolic Ca2+, our findings suggest that the cAMP pathway mediates the reversible assembly and activation of V-ATPase molecules at the apical membrane upon hormonal stimulus}, language = {en} } @article{DamesSchmidtWalzetal.2004, author = {Dames, Petra and Schmidt, R. and Walz, Bernd and Baumann, Otto}, title = {Regulation of vacuolar-type H+-ATPase (vATPase) in blowfly salivary glands}, issn = {0171-9335}, year = {2004}, language = {en} } @article{SchmidtWalz2004, author = {Schmidt, R. and Walz, Bernd}, title = {Serotonin and histamine produce different spatiotemporal Ca2+ signals in blowfly salivary glands}, issn = {0171-9335}, year = {2004}, language = {en} } @article{AltmannToerjekBergeretal.2003, author = {Altmann, Thomas and T{\"o}rjek, Otto and Berger, Dieter and Meyer, Rhonda C. and M{\"u}ssig, Carsten and Schmidt, K. J. and Sorensen, T. R. and Weisshaar, Bernd and Olds-Mitchell, T.}, title = {Establishment of a high-efficiency SNP-based framework marker set for Arabidopsis}, year = {2003}, language = {en} } @article{KarrasHolecBednarovaetal.2018, author = {Karras, Manfred and Holec, Jan and Bednarova, Lucie and Pohl, Radek and Schmidt, Bernd and Stara, Irena G. and Stary, Ivo}, title = {Asymmetric Synthesis of Nonracemic 2-Amino[6]helicenes and Their Self-Assembly into Langmuir Films}, series = {The journal of organic chemistry}, volume = {83}, journal = {The journal of organic chemistry}, number = {10}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.8b00538}, pages = {5523 -- 5538}, year = {2018}, abstract = {Alternative ways of preparing nonracemic 2-amino[6]helicene derivatives were explored. The enantioselective [2 + 2 + 2] cycloisomerization of a nonchiral triyne under Ni(cod)(2)/(R)-QUINAP catalysis delivered the enantioenriched (+)-(P)-2-aminodibenzo[6]helicene derivative in 67\% ee. An ultimate "point-to-helical" chirality transfer was observed in the cyclization of enantiopure triynes mediated by Ni(CO)(2)(PPh3)(2) affording (-)-(M)- or (+)-(P)-7,8-bis(p-tolyl)hexahelicen-2-amine in >99\% ee as well as its benzoderivative in >99\% ee. The latter mode of stereocontrol was inefficient for a 2-aminobenzo[6]helicene congener with an embedded five-membered ring. The rac-, (-)-(M)-, and (+)-(P)-7,8-bis(p-tolyl)hexahelicen-2-amines formed Langmuir monolayers at the air water interface featuring practically identical surface pressure vs mean molecular area isotherms. The corresponding Langmuir-Blodgett films on quartz or silicon substrates were characterized by UV vis/ECD spectroscopy and AFM microscopy, respectively.}, language = {en} } @article{SchultzeSchmidt2018, author = {Schultze, Christiane and Schmidt, Bernd}, title = {Prenylcoumarins in One or Two Steps by a Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination/Cyclization Sequence}, series = {The journal of organic chemistry}, volume = {83}, journal = {The journal of organic chemistry}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.8b00667}, pages = {5210 -- 5224}, year = {2018}, abstract = {The one-pot synthesis of 8-prenylcoumarins from 1,1-dimethylallylated salicylaldehydes and the stabilized ylide [(ethoxycarbonyl)methylene]triphenylphosphorane under microwave conditions was found to have a limited scope. The sequence suffers from a difficult and sometimes low-yielding synthesis of the precursors and from a competing deprenylation upon microwave irradiation. This side reaction occurs in particular with electron rich arenes with two or more alkoxy groups at adjacent positions, a prominent substitution pattern in naturally occurring 8-prenylcoumarins. Both limitations of this one-step sequence were overcome by a two-step synthesis consisting of a microwave-promoted tandem allyl ether Claisen rearrangement/Wittig olefination and a subsequent olefin cross metathesis with 2-methyl-2-butene. The cross metathesis step proceeds with a high selectivity and yields exclusively the desired prenyl, rather than the alternative crotyl substituent. Several naturally occurring 8-prenylcoumarins that were previously inaccessible have been synthesized in good overall yields along this route.}, language = {en} } @article{KarrasDabrowskiPohletal.2018, author = {Karras, Manfred and Dabrowski, Michal and Pohl, Radek and Rybacek, Jiri and Vacek, Jaroslav and Bednarova, Lucie and Grela, Karol and Stary, Ivo and Stara, Irena G. and Schmidt, Bernd}, title = {Helicenes as Chirality-Inducing Groups in Transition-Metal Catalysis}, series = {Chemistry - a European journal}, volume = {24}, journal = {Chemistry - a European journal}, number = {43}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201802786}, pages = {10994 -- 10998}, year = {2018}, abstract = {Helical chirality is a novel enantioselectivity-inducing property in transition-metal-catalyzed transformations. The principle is illustrated herein for the example of asymmetric olefin metathesis. This work reports the synthesis of the first helically chiral Ru-NHC alkylidene complex from an aminohelicene-derived imidazolium salt, which was ligated to the first generation Hoveyda-Grubbs catalyst. Kinetic data were acquired for benchmark test reactions and compared to an achiral catalyst. The helically chiral Ru-catalyst was evaluated in asymmetric ring-closing metathesis (RCM) and ring-opening metathesis-cross-metathesis (ROM/CM) reactions, which proceeded with promising levels of enantioselectivity. Extensive NMR-spectroscopic investigations and a DFT geometry optimization were performed. These results led to a topographic steric map and calculation of percent-buried-volume values for each quadrant around the metal center.}, language = {en} } @article{OtteSchmidt2019, author = {Otte, Fabian and Schmidt, Bernd}, title = {Matsuda-Heck Arylation of Glycals for the Stereoselective Synthesis of Aryl C-Glycosides}, series = {The journal of organic chemistry}, volume = {84}, journal = {The journal of organic chemistry}, number = {22}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.9b02410}, pages = {14816 -- 14829}, year = {2019}, abstract = {The methoxymethyl-protected glycal L-amicetal, synthesized de novo from L-ethyl lactate through tandem ring-closing metathesis-isomerization sequence, undergoes a highly trans-diastereoselective Heck-type coupling reaction with various arene diazonium salts to furnish 2,3-unsaturated aryl C-glycosides in moderate to excellent yields. The products can be further functionalized, e.g., by hydrogenation, epoxidation, or dihydroxylation to furnish 2,3,6-tridesoxy, 2,3-anhydro-6-desoxy, or 6-desoxy aryl C-glycosides, respectively. The method was applied to the synthesis of an a-configured 6-desoxy-gliflozin derivative.}, language = {en} } @article{SchultzeSchmidt2018, author = {Schultze, Christiane and Schmidt, Bernd}, title = {Ring-closing-metathesis-based synthesis of annellated coumarins from 8-allylcoumarins}, series = {Beilstein journal of organic chemistry}, volume = {14}, journal = {Beilstein journal of organic chemistry}, publisher = {Beilstein-Institut zur F{\"o}rderung der Chemischen Wissenschaften}, address = {Frankfurt, Main}, issn = {1860-5397}, doi = {10.3762/bjoc.14.278}, pages = {2991 -- 2998}, year = {2018}, abstract = {8-Allylcoumarins are conveniently accessible through a microwave-promoted tandem Claisen rearrangement/Wittig olefination/cyclization sequence. They serve as a versatile platform for the annellation of five- to seven-membered rings using ring-closing olefin metathesis (RCM). Furano-, pyrano-, oxepino- and azepinocoumarins were synthesized from the same set of precursors using Ru-catalyzed double bond isomerizations and RCM in a defined order. One class of products, pyrano[2,3-f]chromene-2,8-diones, were inaccessible through direct RCM of an acrylate, but became available from the analogous allyl ether via an assisted tandem catalytic RCM/allylic oxidation sequence.}, language = {en} } @article{NguyenLeeAudoerschetal.2018, author = {Nguyen, Hiep N. and Lee, Hyeunjoo and Aud{\"o}rsch, Stephan and Reznichenko, Alexander L. and Nawara-Hultzsch, Agnieszka J. and Schmidt, Bernd and Hultzsch, Kai C.}, title = {Asymmetric Intra- and Intermolecular Hydroamination Catalyzed by 3,3′-Bis(trisarylsilyl)- and 3,3′-Bis(arylalkylsilyl)-Substituted Binaphtholate Rare-Earth-Metal Complexes}, series = {Organometallics}, volume = {37}, journal = {Organometallics}, number = {23}, publisher = {American Chemical Society}, address = {Washington}, issn = {0276-7333}, doi = {10.1021/acs.organomet.8b00510}, pages = {4358 -- 4379}, year = {2018}, abstract = {The series of novel 3,3′-bis(trisarylsilyl)- and 3,3′-bis(arylalkylsilyl)-substituted binaphtholate rare-earth-metal complexes 2a-i (SiR3 = Si(o-biphenylene)Ph (a), SiCyPh2 (b), Si-t-BuPh2 (c), Si(i-Pr)3 (d), SiCy2Ph (e), Si(2-tolyl)Ph2 (f), Si(4-t-Bu-C6H4)3 (g), Si(4-MeO-C6H4)Ph2 (h), SiBnPh2 (i)) have been prepared via arene elimination from [Ln(o-C6H4CH2NMe2)3] (Ln = Y, Lu) and the corresponding 3,3′-bis(silyl)-substituted binaphthol. The complexes exhibit high catalytic activity in the hydroamination/cyclization of aminoalkenes, with activities exceeding 1000 h-1 for (R)-2f-Ln, (R)-2g-Ln, and (R)-2h-Ln in the cyclization of 2,2-diphenylpent-4-enylamine (3a) at 25 °C, while the rigid dibenzosilole-substituted complexes (R)-2a-Ln and the triisopropylsilyl-substituted complexes (R)-2d-Ln exhibited the lowest activity in the range of 150-270 h-1. Catalysts (R)-2b-Lu, (R)-2c-Lu, (R)-2f-Lu, and (R)-2i-Lu provide the highest selectivities for the majority of the substrates, while the yttrium congeners are usually less selective. The highest enantioselectivities of 96\% ee were observed using (R)-2a-Lu and (R)-2c-Lu in the cyclization of (4E)-2,2,5-triphenylpent-4-enylamine (9). The reactions show apparently zero-order rate dependence on substrate concentration and first-order rate dependence on catalyst concentration, with some reactions exhibiting a slightly accelerated rate at high conversion due to a shift in the equilibrium between a less active, higher coordinate catalyst species in favor of a more active, lower coordinate species as a result of weaker binding of the hydroamination product in comparison to the aminoalkene substrate. The shift in equilibrium from the higher to the lower coordinate species is also entropically favored at elevated temperatures, which results in an unusual increase in selectivity in the cyclization of 2,2-dimethylpent-4-enylamine (3d), presumably due to a higher selectivity of the lower coordinate catalyst species. All binaphtholate yttrium complexes, except (R)-2a-Y, are catalytically active in the intermolecular hydroamination of benzylamines with terminal alkenes. The highest selectivity of 66\% ee was observed for the reaction of benzylamine with 4-phenyl-1-butene using (R)-2h-Y at 110 °C.}, language = {en} } @article{HolecRybačekVaceketal.2019, author = {Holec, Jan and Ryb{\´a}ček, Jiř{\´i} and Vacek, Jaroslav and Karras, Manfred and Bedn{\´a}rov{\´a}, Lucie and Budesinsky, Milos and Slusna, Michaela and Holy, Petr and Schmidt, Bernd and Star{\´a}, Irena G. and Star{\´y}, Ivo}, title = {Chirality-Controlled Self-Assembly of Amphiphilic Dibenzo[6]helicenes into Langmuir-Blodgett Thin Films}, series = {Chemistry - a European journal}, volume = {25}, journal = {Chemistry - a European journal}, number = {49}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201901695}, pages = {11494 -- 11502}, year = {2019}, abstract = {Racemic and highly enantioenriched 3-methoxycarbonyl, 3-carboxy, and 3-hydroxymethyl derivatives of dibenzo[6]helicene were prepared. The Langmuir layers of these helicenes were formed at the air-water interface and transferred onto solid substrates to afford Langmuir-Blodgett films, which were then studied by ambient atomic force microscopy and (chir)optical spectroscopy. Significant differences were found in the behaviour of the Langmuir layers as well as in the morphology, UV/Vis, electronic circular dichroism (ECD), and fluorescence spectra of the Langmuir-Blodgett thin films depending on the molecular chirality and nature of the polar group. The experimental results were supported by molecular dynamics simulations.}, language = {en} } @article{HermannsSchmidt2018, author = {Hermanns, Jolanda and Schmidt, Bernd}, title = {Developing and Applying Stepped Supporting Tools in Organic Chemistry To Promote Students' Self-Regulated Learning}, series = {Journal of chemical education}, volume = {96}, journal = {Journal of chemical education}, number = {1}, publisher = {American Chemical Society}, address = {Washington}, issn = {0021-9584}, doi = {10.1021/acs.jchemed.8b00565}, pages = {47 -- 52}, year = {2018}, abstract = {Stepped supporting tools were developed and used in the university seminar Organic Chemistry taken by nonmajor chemistry students, which supported self-regulated learning. These supporting tools were also used for accompanying homework, which included a QR code that led to additional supporting tools. The application of stepped supporting tools in the seminars was evaluated by a four-item Likert scale. The students assessed the tools as a helpful instrument for solving tasks in chemistry.}, language = {en} } @article{RiemerShipmanWessigetal.2019, author = {Riemer, Nastja and Shipman, Michael and Wessig, Pablo and Schmidt, Bernd}, title = {Iterative arylation of itaconimides with diazonium salts through electrophilic palladium catalysis}, series = {The journal of organic chemistry}, volume = {84}, journal = {The journal of organic chemistry}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.9b00627}, pages = {5732 -- 5746}, year = {2019}, abstract = {N-Arylitaconimides, accessible from maleic anhydride, anilines, and paraformaldehyde, react with arene diazonium salts in Pd-catalyzed Matsuda-Heck arylation to the pharmacologically relevant E-configured 3-arylmethylidene pyrrolidine-2,5-diones (also known as arylmethylidene succinimides) through exo-selective beta-H-elimination. The coupling proceeds at ambient temperature with the simple and easy-to-handle precatalyst Pd-II-acetate under ligandand base-free conditions. Notable features are high isolated yields, regio- and stereoselectivities, and short reaction times. In a comparative investigation, aryl iodides, bromides, and triflates were shown to be inferior coupling reagents in this reaction. The 3-arylmethylidene pyrrolidine-2,5-diones undergo second Matsuda-Heck coupling, which proceeds via endo-selective beta-H-elimination to give diarylmethyl-substituted maleimides as coupling products. These products can also be accessed in one flask by sequential addition of different arene diazonium salts to the starting itaconimide. The potential of 3-arylmethylidene succinimides as photoswitches was tested. Upon irradiation of the E-isomer at 300 nm, partial isomerization to the Z-isomer (E/Z = 65:35 in the photostationary state) was observed. The isomerization was found to be nearly completely reversible by irradiating the mixture at 400 nm.}, language = {en} } @article{RiemerCoswigShipmanetal.2018, author = {Riemer, Nastja and Coswig, Christin and Shipman, Michael and Schmidt, Bernd}, title = {Palladium-catalyzed cross-coupling of arenediazonium salts with organoindium or organobismuth reagents}, series = {Synlett : accounts and rapid communications in synthetic organic chemistry}, volume = {29}, journal = {Synlett : accounts and rapid communications in synthetic organic chemistry}, number = {18}, publisher = {Georg Thieme Verlag KG}, address = {Stuttgart}, issn = {0936-5214}, doi = {10.1055/s-0037-1611001}, pages = {2427 -- 2431}, year = {2018}, abstract = {Arylindium and isolated triarylbismuth compounds generated in situ react as nucleophiles with arenediazonium salts in palladium-catalyzed cross-coupling reactions to give substituted biphenyls.}, language = {en} } @misc{SchmidtHattenbergerBergmannLabitzkeetal.2017, author = {Schmidt-Hattenberger, Cornelia and Bergmann, Peter and Labitzke, Tim and Pommerencke, Julia and Rippe, Dennis and Wagner, Florian and Wiese, Bernd}, title = {Monitoring the complete life-cycle of a CO2 storage reservoir-Demonstration of applicability of geoelectrical imaging}, series = {13th International Conference on Greenhouse Gas Control Technologies (GHGT)}, volume = {114}, journal = {13th International Conference on Greenhouse Gas Control Technologies (GHGT)}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1876-6102}, doi = {10.1016/j.egypro.2017.03.1526}, pages = {3948 -- 3955}, year = {2017}, abstract = {In this paper, the applicability of deep downhole geoelectrical monitoring for detecting CO2 related signatures is evaluated after a nearly ten year period of CO2 storage at the Ketzin pilot site. Deep downhole electrode arrays have been studied as part of a multi-physical monitoring concept at four CO2 pilot test sites worldwide so far. For these sites, it was considered important to implement the geoelectrical method into the measurement program of tracking the CO2 plume. Analyzing the example of the Ketzin site, it can be seen that during all phases of the CO2 storage reservoir development the resistivity measurements and their corresponding tomographic interpretation contribute in a beneficial manner to the measurement, monitoring and verification (MMV) protocol. The most important impact of a permanent electrode array is its potential as tool for estimating reservoir saturations.}, language = {en} } @article{KwesigaSperlichSchmidt2021, author = {Kwesiga, George and Sperlich, Eric and Schmidt, Bernd}, title = {Scope and applications of 2,3-oxidative aryl rearrangements for the synthesis of isoflavone natural products}, series = {The journal of organic chemistry}, volume = {86}, journal = {The journal of organic chemistry}, number = {15}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.1c01375}, pages = {10699 -- 10712}, year = {2021}, abstract = {The reaction of flavanones with hypervalent iodine reagents was investigated with a view to the synthesis of naturally occurring isoflavones. In contrast to several previous reports in the literature, we did not observe the formation of any benzofurans via a ring contraction pathway, but could isolate only isoflavones, resulting from an oxidative 2,3-aryl rearrangement, and flavones, resulting from an oxidation of the flavanones. Although the 2,3-oxidative rearrangement allows a synthetically useful approach toward some isoflavone natural products due to the convenient accessibility of the required starting materials, the overall synthetic utility and generality of the reaction appear to be more limited than previous literature reports suggest.}, language = {en} } @article{SperlichKellingKwesigaetal.2022, author = {Sperlich, Eric and Kelling, Alexandra and Kwesiga, George and Schmidt, Bernd}, title = {Intermolecular interactions in the solid-state structures of isoflavones}, series = {CrystEngComm / The Royal Society of Chemistry}, volume = {24}, journal = {CrystEngComm / The Royal Society of Chemistry}, number = {26}, publisher = {Royal Society of Chemistry}, address = {London}, issn = {1466-8033}, doi = {10.1039/d2ce00169a}, pages = {4731 -- 4739}, year = {2022}, abstract = {The molecular structures of three closely related isoflavones have been determined by single crystal X-ray diffraction and have been analysed by geometry matching with the CSD, Hirshfeld surface analysis and analysis of stacking interactions with the Aromatic Analyser program (CSD). The formation of the supramolecular structure by non-covalent interactions was studied and substantial differences in the macroscopic properties e.g., the solubility, were correlated with hydrogen bonding and pi-stacking interactions. Moreover, a correlation between the supramolecular structure, the torsion angle (between benzopyran group and aryl group), and macroscopic properties was determined in the three compounds.}, language = {en} } @misc{SchmidtBaumannWalz2008, author = {Schmidt, Ruth and Baumann, Otto and Walz, Bernd}, title = {cAMP potentiates InsP3-induced Ca2+ release from the endoplasmic reticulum in blowfly salivary glands}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {842}, issn = {1866-8372}, doi = {10.25932/publishup-42977}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429770}, pages = {13}, year = {2008}, abstract = {Background Serotonin induces fluid secretion from Calliphora salivary glands by the parallel activation of the InsP3/Ca2+ and cAMP signaling pathways. We investigated whether cAMP affects 5-HT-induced Ca2+ signaling and InsP3-induced Ca2+ release from the endoplasmic reticulum (ER). Results Increasing intracellular cAMP level by bath application of forskolin, IBMX or cAMP in the continuous presence of threshold 5-HT concentrations converted oscillatory [Ca2+]i changes into a sustained increase. Intraluminal Ca2+ measurements in the ER of ß-escin-permeabilized glands with mag-fura-2 revealed that cAMP augmented InsP3-induced Ca2+ release in a concentration-dependent manner. This indicated that cAMP sensitized the InsP3 receptor Ca2+ channel for InsP3. By using cAMP analogs that activated either protein kinase A (PKA) or Epac and the application of PKA-inhibitors, we found that cAMP-induced augmentation of InsP3-induced Ca2+ release was mediated by PKA not by Epac. Recordings of the transepithelial potential of the glands suggested that cAMP sensitized the InsP3/Ca2+ signaling pathway for 5-HT, because IBMX potentiated Ca2+-dependent Cl- transport activated by a threshold 5-HT concentration. Conclusion This report shows, for the first time for an insect system, that cAMP can potentiate InsP3-induced Ca2+ release from the ER in a PKA-dependent manner, and that this crosstalk between cAMP and InsP3/Ca2+ signaling pathways enhances transepithelial electrolyte transport.}, language = {en} } @article{TobieGieseHurfordetal.2010, author = {Tobie, Gabriel and Giese, Bernd and Hurford, Terry Anthony and Lopes, Rosaly M. and Nimmo, Francis and Postberg, Frank and Retherford, Kurt D. and Schmidt, J{\"u}rgen and Spencer, John R. and Tokano, Tetsuya and Turtle, Elizabeth P.}, title = {Surface, subsurface and atmosphere exchanges on the satellites of the outer solar system}, issn = {0038-6308}, doi = {10.1007/s11214-010-9641-3}, year = {2010}, abstract = {The surface morphology of icy moons is affected by several processes implicating exchanges between their subsurfaces and atmospheres (if any). The possible exchange of material between the subsurface and the surface is mainly determined by the mechanical properties of the lithosphere, which isolates the deep, warm and ductile ice material from the cold surface conditions. Exchanges through this layer occur only if it is sufficiently thin and/or if it is fractured owing to tectonic stresses, melt intrusion or impact cratering. If such conditions are met, cryomagma can be released, erupting fresh volatile-rich materials onto the surface. For a very few icy moons (Titan, Triton, Enceladus), the emission of gas associated with cryovolcanic activity is sufficiently large to generate an atmosphere, either long- lived or transient. For those moons, atmosphere-driven processes such as cryovolcanic plume deposition, phase transitions of condensable materials and wind interactions continuously re-shape their surfaces, and are able to transport cryovolcanically generated materials on a global scale. In this chapter, we discuss the physics of these different exchange processes and how they affect the evolution of the satellites' surfaces.}, language = {en} } @article{Schmidt2006, author = {Schmidt, Bernd}, title = {Olefin metathesis and isomerization : from undesired side reactions to useful synthetic methodology}, doi = {10.1016/j.molcata.2006.03.026}, year = {2006}, abstract = {Conversion of ruthenium carbene complexes to ruthenium hydride complexes by organometallic transformations in situ opens up interesting synthetic perspectives. In this account the use of Grubbs' catalyst to synthesize pent-4- enals selectively from diallyl- and allyl homoallyl ethers and scope and limitations of a Tandem RCM-isomerization sequence for the synthesis of cyclic enol ethers are discussed. (c) 2006 Elsevier B.V. All rights reserved}, language = {en} } @article{SchmidtNave2006, author = {Schmidt, Bernd and Nave, Stefan}, title = {Control of ring size selectivity by substrate directable RCM}, doi = {10.1039/B604359c}, year = {2006}, abstract = {Hydroxy groups may exert strong catalyst-directing effects in olefin metathesis reactions, which are exploited for a ring size-selective RCM reaction}, language = {en} } @article{SchmidtElizarovBergeretal.2014, author = {Schmidt, Bernd and Elizarov, Nelli and Berger, Ren{\´e} and H{\"o}lter, Frank}, title = {Scope and limitations of the Heck-Matsuda-coupling of phenol diazonium salts and styrenes: a protecting-group economic synthesis of phenolic stilbenes}, issn = {1477-0520}, doi = {10.1039/C3OB40420J}, year = {2014}, abstract = {4-Phenol diazonium salts undergo Pd-catalyzed Heck reactions with various styrenes to 4{\"i}-hydroxy stilbenes. In almost all cases higher yields and fewer side products were observed, compared to the analogous 4-methoxy benzene diazonium salts. In contrast, the reaction fails completely with 2- and 3-phenol diazonium salts. For these substitution patterns the methoxy-substituted derivatives are superior.}, language = {en} } @article{SchmidtBerger2013, author = {Schmidt, Bernd and Berger, Ren{\´e}}, title = {A deacetylation-diazotation-coupling sequence - palladium-catalyzed CC bond formation with acetanilides as formal leaving groups}, series = {Advanced synthesis \& catalysis}, volume = {355}, journal = {Advanced synthesis \& catalysis}, number = {2-3}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1615-4150}, doi = {10.1002/adsc.201200929}, pages = {463 -- 476}, year = {2013}, abstract = {Acetanilides can be deacetylated and diazotized in situ, and subsequently used in Pd-catalyzed coupling reactions without isolation of the diazonium intermediate. Heck reactions, Suzuki cross-coupling reactions, and a Pd-catalyzed [2+2+1]cycloaddition have been investigated as terminating CC bond-forming steps of this one-flask sequence. The sequence does not require the exchange of solvents or removal of by-products between the individual steps, but proceeds by addition of reagents and catalysts in due course.}, language = {en} } @article{SchmidtWernerKellingetal.2010, author = {Schmidt, Bernd and Werner, Frank and Kelling, Alexandra and Schilde, Uwe}, title = {The reaction of 3,4-dihydro-2H-pyran with oxalyl chloride : formation and crystal structure analysis of an unexpected bicyclic product}, issn = {0022-152X}, year = {2010}, abstract = {3,4-Dihydro-2-H-pyran and oxalyl chloride react, depending on the conditions, to keto esters, a pyran-3- carboxylic acid or derivatives thereof, or to an hitherto unknown bicyclic acetal containing a vinyl chloride moiety. The structure of the latter product has been unambiguously elucidated by single-crystal X-ray structure analysis. A mechanism for its formation is proposed.}, language = {en} } @article{SchmidtKrehlHauke2013, author = {Schmidt, Bernd and Krehl, Stefan and Hauke, Sylvia}, title = {Assisted tandem catalytic cross metathesis-oxidation in one flask from styrenes to 1,2-Diketones and further to quinoxalines}, series = {The journal of organic chemistry}, volume = {78}, journal = {The journal of organic chemistry}, number = {11}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo4005684}, pages = {5427 -- 5435}, year = {2013}, abstract = {1,2-Diketones were synthesized from styrenes by combining a cross metathesis and a Ru-catalyzed alkene oxidation to an assisted tandem catalytic sequence. The synthesis relies on the use of just one metathesis precatalyst, which was in situ converted to the oxidation catalyst by addition of an alkyl hydroperoxide as a chemical trigger and oxidant. The one-flask sequence can be extended beyond 1,2-diketones to quinoxalines, by condensation of the oxidation products with ortho-phenylenediamine.}, language = {en} } @article{VossSchmidtWalzetal.2009, author = {Voss, Martin and Schmidt, Ruth and Walz, Bernd and Baumann, Otto}, title = {Stimulus-induced translocation of the protein kinase A catalytic subunit to the apical membrane in blowfly salivary glands}, issn = {0302-766X}, doi = {10.1007/s00441-008-0673-x}, year = {2009}, abstract = {Secretion in blowfly (Calliphora vicina) salivary glands is regulated by the neurohormone serotonin (5-HT), which activates the InsP(3)/Ca2+ pathway and the cAMP/protein kinase A (PKA) pathway in the secretory cells. The latter signaling cascade induces the activation of a vacuolar H+-ATPase on the apical membrane. Here, we have determined the distribution of PKA by using antibodies against the PKA regulatory subunit-II (PKA-RII) and the PKA catalytic subunit (PKA-C) of Drosophila. PKA is present in high concentrations within the secretory cells. PKA-RII and PKA-C co-distribute in non-stimulated glands, being enriched in the basal portion of the secretory cells. Exposure to 8-CPT-cAMP or 5-HT induces the translocation of PKA-C to the apical membrane, whereas the PKA-RII distribution remains unchanged. The recruitment of PKA-C to the apical membrane corroborates our hypothesis that vacuolar H+-ATPase, which is enriched in this membrane domain, is a target protein for PKA.}, language = {en} } @article{SchmidtRiemerKarras2013, author = {Schmidt, Bernd and Riemer, Martin and Karras, Manfred}, title = {2,2 '-Biphenols via protecting group-free thermal or microwave-accelerated suzuki-miyaura coupling in water}, series = {The journal of organic chemistry}, volume = {78}, journal = {The journal of organic chemistry}, number = {17}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo401398n}, pages = {8680 -- 8688}, year = {2013}, abstract = {User-friendly protocols for the protecting group-free synthesis of 2,2'-biphenols via Suzuki-Miyaura coupling of o-halophenols and o-boronophenol are presented. The reactions proceed in water in the presence of simple additives such as K2CO3, KOH, KF, or TBAF and with commercially available Pd/C as precatalyst. Expensive or laboriously synthesized ligands or other additives are not required. In the case of bromophenols, efficient rate acceleration and short reaction times were accomplished by microwave irradiation.}, language = {en} } @article{SchmidtKunz2013, author = {Schmidt, Bernd and Kunz, Oliver}, title = {Stereoselective synthesis of dienyl phosphonates via extended tethered ring-closing metathesis}, series = {Organic letters}, volume = {15}, journal = {Organic letters}, number = {17}, publisher = {American Chemical Society}, address = {Washington}, issn = {1523-7060}, doi = {10.1021/ol4020078}, pages = {4470 -- 4473}, year = {2013}, abstract = {Allylphosphonates of allylic alcohols were converted to conjugated dienyl phosphonates in a one-flask reaction, comprising a ring-closing metathesis (RCM), a base-induced ring-opening, and an alkylation. The ring-opening proceeds with very high diastereoselectivity, giving exclusively the (1Z,3E)-configured dienes. Single diastereomers and mixtures of diastereomers can be used as starting materials without noticeable effect on the diastereoselectivity of the sequence.}, language = {en} } @article{MeierCzechMetteetal.1994, author = {Meier, Bernd and Czech, Olaf and Mette, Dieter and Sachs, Conrad and Schmeer, Ernst and Schmidt, Volkhard and Klaus, Elisabeth and Neumann, Karin}, title = {Arbeitslehre aktuell : Schwerpunkt Technik ; Bd. 1 Lehrerhandbuch}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, pages = {96 S.}, year = {1994}, language = {de} } @book{MeierCzechMetteetal.1995, author = {Meier, Bernd and Czech, Olaf and Mette, Dieter and Sachs, Conrad and Schmeer, Ernst and Schmidt, Volkhard and Klaus, Elisabeth and Neumann, Karin}, title = {Arbeitslehre aktuell : Schwerpunkt Technik ; Bd. 2 Lehrerhandbuch}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, isbn = {3-486-88731-9}, pages = {96 S.}, year = {1995}, language = {de} } @article{SchmidtNave2006, author = {Schmidt, Bernd and Nave, Stefan}, title = {Palladium-catalyzed O-allylation of alpha-hydroxy carbonyl compounds}, doi = {10.1002/adsc.200505361}, year = {2006}, abstract = {alpha-Hydroxy carbonyl compounds undergo smooth O-allylation using allylic carbonates and Pd(0) catalysts. This method has significant advantages over other O-allylation methods as it provides a solution to several problems previously observed for this synthetic transformation}, language = {en} } @article{PostbergKempfSchmidtetal.2009, author = {Postberg, Frank and Kempf, Sascha and Schmidt, J{\"u}rgen and Brilliantov, Nikolai V. and Beinsen, Alexander and Abel, Bernd and Buck, Udo and Srama, Ralf}, title = {Sodium salts in E-ring ice grains from an ocean below the surface of Enceladus}, issn = {0028-0836}, doi = {10.1038/Nature08046}, year = {2009}, abstract = {Saturn's moon Enceladus emits plumes of water vapour and ice particles from fractures near its south pole(1-5), suggesting the possibility of a subsurface ocean(5-7). These plume particles are the dominant source of Saturn's E ring(7,8). A previous in situ analysis(9) of these particles concluded that the minor organic or siliceous components, identified in many ice grains, could be evidence for interaction between Enceladus' rocky core and liquid water(9,10). It was not clear, however, whether the liquid is still present today or whether it has frozen. Here we report the identification of a population of E-ring grains that are rich in sodium salts (similar to 0.5- 2\% by mass), which can arise only if the plumes originate from liquid water. The abundance of various salt components in these particles, as well as the inferred basic pH, exhibit a compelling similarity to the predicted composition of a subsurface Enceladus ocean in contact with its rock core(11). The plume vapour is expected to be free of atomic sodium. Thus, the absence of sodium from optical spectra(12) is in good agreement with our results. In the E ring the upper limit for spectroscopy(12) is insufficiently sensitive to detect the concentrations we found.}, language = {en} } @article{SchmidtStaude2009, author = {Schmidt, Bernd and Staude, Lucia}, title = {Ring-size-selective enyne metathesis as a tool for desymmetrization of an enantiopure C-2-symmetric building block}, issn = {0022-3263}, doi = {10.1021/Jo9018649}, year = {2009}, abstract = {The enantiomerically pure C-2-syrnmetrical hexa-1,5-diene-3,4-diol is selectively monopropargylated. The products undergo ring-closing enyne metathesis to give exclusively dihydropyrans as single stereoisomers. An unprotected hydroxy group is identified as the factor controlling the ring-size selectivity.}, language = {en} } @article{SchmidtHoelter2009, author = {Schmidt, Bernd and Hoelter, Frank}, title = {A stereodivergent synthesis of all stereoisomers of centrolobine : control of selectivity by a protecting-group manipulation}, issn = {0947-6539}, doi = {10.1002/chem.200902053}, year = {2009}, abstract = {All stereoisomers of the natural product centrolobine are selectively synthesized, by starting from a common precursor. Key steps are an enantioselective allylation with enantiomerically pure allylsilanes, a tandem ring-closing metathesis-isomerization reaction, and a Heck reaction by using an arene diazonium salt. By choosing appropriate conditions for the final deprotection step, either the cis-configured centrolobines or their epimers are selectively obtained.}, language = {en} } @article{SchmidtKunz2013, author = {Schmidt, Bernd and Kunz, Oliver}, title = {Bidirectional cross metathesis and ring-closing metathesis/ring opening of a C-2-symmetric building block: a strategy for the synthesis of decanolide natural products}, series = {Beilstein journal of organic chemistry}, volume = {9}, journal = {Beilstein journal of organic chemistry}, publisher = {Beilstein-Institut zur F{\"o}rderung der Chemischen Wissenschaften}, address = {Frankfurt, Main}, issn = {1860-5397}, doi = {10.3762/bjoc.9.289}, pages = {2544 -- 2555}, year = {2013}, abstract = {Starting from the conveniently available ex-chiral pool building block (R,R)-hexa-1,5-diene-3,4-diol, the ten-membered ring lactones stagonolide E and curvulide A were synthesized using a bidirectional olefin-metathesis functionalization of the terminal double bonds. Key steps are (i) a site-selective cross metathesis, (ii) a highly diastereoselective extended tethered RCM to furnish a (Z,E)-configured dienyl carboxylic acid and (iii) a Ru-lipase-catalyzed dynamic kinetic resolution to establish the desired configuration at C9. Ring closure was accomplished by macrolactonization. Curvulide A was synthesized from stagonolide E through Sharpless epoxidation.}, language = {en} } @article{SchmidtHauke2014, author = {Schmidt, Bernd and Hauke, Sylvia}, title = {Cross metathesis of allyl alcohols: how to suppress and how to promote double bond isomerization}, issn = {1477-0520}, doi = {10.1039/c3ob40167g}, year = {2014}, abstract = {Under standard conditions the cross metathesis of allyl alcohols and methyl acrylate is accompanied by the formation of ketones, resulting from uncontrolled and undesired double bond isomerization. By conducting the CM in the presence of phenol, the catalyst loading and the reaction time required for quantiative conversion can be reduced, and isomerization can be suppressed. On the other hand, consecutive isomerization can be deliberately promoted by evaporating excess methyl acrylate after completing cross metathesis and by adding a base or silane as chemical triggers.}, language = {en} } @article{SchmidtElizarovBergeretal.2013, author = {Schmidt, Bernd and Elizarov, Nelli and Berger, Ren{\´e} and Petersen, Monib H.}, title = {From paracetamol to rolipram and derivatives - application of deacetylation-diazotation sequences and palladium-catalyzed matsuda-heck reaction}, series = {Synthesis}, volume = {45}, journal = {Synthesis}, number = {9}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0032-1316874}, pages = {1174 -- 1180}, year = {2013}, abstract = {A six-step synthesis of the antidepressant rolipram from the popular analgetic 4-acetamidophenol (paracetamol) is described. The steps include oxidative functionalization of the aromatic core, diazonium salt formation via deacetylation-diazotation, Matsuda-Heck reaction, conjugate addition of nitromethane, and hydrogenative cyclization.}, language = {en} } @article{SchmidtBergerKellingetal.2011, author = {Schmidt, Bernd and Berger, Ren{\´e} and Kelling, Alexandra and Schilde, Uwe}, title = {Pd-Catalyzed [2+2+1] coupling of alkynes and arenes phenol diazonium salts as mechanistic trapdoors}, series = {Chemistry - a European journal}, volume = {17}, journal = {Chemistry - a European journal}, number = {25}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0947-6539}, doi = {10.1002/chem.201100609}, pages = {7032 -- 7040}, year = {2011}, abstract = {Alkynes and phenol diazonium salts undergo a Pd-catalyzed [2+2+1] cyclization reaction to spiro[4,5]decatetraene-7-ones. This structure was confirmed for one example by X-ray single-crystal structure analysis. The reaction is believed to proceed through oxidative addition of the phenol diazonium cation to Pd(0), subsequent insertion of two alkynes, followed by irreversible spirocyclization.}, language = {en} } @article{SchmidtHoelterKellingetal.2011, author = {Schmidt, Bernd and H{\"o}lter, Frank and Kelling, Alexandra and Schilde, Uwe}, title = {Pd-Catalyzed arylation reactions with phenol diazonium salts application in the synthesis of diarylheptanoids}, series = {The journal of organic chemistry}, volume = {76}, journal = {The journal of organic chemistry}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo2002787}, pages = {3357 -- 3365}, year = {2011}, abstract = {The first total synthesis of the natural product (3S,7R)-5,6-dehydro-de-O-methyl centrolobine and various analogues is reported, using a highly regio- and diastereoselective Mizoroki-Heck reaction of phenol diazonium salts and enantiopure dihydropyrans. The assigned relative configuration was confirmed by single-crystal X-ray structure analysis, but a revision of the absolute configuration is proposed based on polarimetric measurement.}, language = {en} } @article{SchmidtElizarovSchildeetal.2015, author = {Schmidt, Bernd and Elizarov, Nelli and Schilde, Uwe and Kelling, Alexandra}, title = {Dual Role of Acetanilides: Traceless Removal of a Directing Group through Deacetylation/Diazotation and Palladium-Catalyzed C-C-Coupling Reactions}, series = {The journal of organic chemistry}, volume = {80}, journal = {The journal of organic chemistry}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.5b00272}, pages = {4223 -- 4234}, year = {2015}, abstract = {The acetamide group enables regioselective oxidative ortho-C-H activation reactions, such as Pd-catalyzed acylation. The synthetic utility of these transformations can be significantly enhanced by using the acetamide as a quasi-leaving group in a subsequent conventional Pd-catalyzed coupling or cross-coupling reaction. The concept is illustrated herein for the synthesis of o-alkenyl- and o-arylphenones, which have potential for the synthesis of arylated aromatic heterocycles.}, language = {en} } @article{SchmidtKrehlKellingetal.2012, author = {Schmidt, Bernd and Krehl, Stefan and Kelling, Alexandra and Schilde, Uwe}, title = {Synthesis of 8-Aryl-Substituted Coumarins based on Ring-Closing Metathesis and Suzuki-Miyaura coupling - synthesis of a Furyl Coumarin natural product from Galipea panamensis}, series = {The journal of organic chemistry}, volume = {77}, journal = {The journal of organic chemistry}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo2026564}, pages = {2360 -- 2367}, year = {2012}, abstract = {The synthesis of 7-methoxy-8-(4-methyl-3-furyl)-2H-chromen-2-one, a natural product with antileishmanial activity recently isolated from the plant Galipea panamensis, is described. The key step is a Suzuki-Miyaura coupling of a furan-3-boronic acid and an 8-halocoumarin, which is advantageously synthesized using a ring-closing metathesis reaction. Several non-natural analogues are also available along these lines.}, language = {en} } @article{SchmidtKunz2012, author = {Schmidt, Bernd and Kunz, Oliver}, title = {alpha,beta-Unsaturated delta-Valerolactones through RCM-Isomerization Sequence}, series = {Synlett : accounts and rapid communications in synthetic organic chemistry}, journal = {Synlett : accounts and rapid communications in synthetic organic chemistry}, number = {6}, publisher = {Thieme}, address = {Stuttgart}, issn = {0936-5214}, doi = {10.1055/s-0031-1290488}, pages = {851 -- 854}, year = {2012}, abstract = {alpha,beta-Unsaturated d-lactones are accessible via a sequential ring-closing metathesis (RCM) double-bond migration reaction starting from butenoates of allyl alcohols. This approach proceeds efficiently with lower catalyst loadings and higher initial substrate concentrations compared to the alternative RCM of acrylates derived from homoallylic alcohols.}, language = {en} } @article{KempfSramaGruenetal.2012, author = {Kempf, Sascha and Srama, Ralf and Gr{\"u}n, Eberhard and Mocker, Anna and Postberg, Frank and Hillier, Jon K. and Horanyi, Mihaly and Sternovsky, Zoltan and Abel, Bernd and Beinsen, Alexander and Thissen, Roland and Schmidt, J{\"u}rgen and Spahn, Frank and Altobelli, Nicolas}, title = {Linear high resolution dust mass spectrometer for a mission to the Galilean satellites}, series = {Planetary and space science}, volume = {65}, journal = {Planetary and space science}, number = {1}, publisher = {Elsevier}, address = {Oxford}, issn = {0032-0633}, doi = {10.1016/j.pss.2011.12.019}, pages = {10 -- 20}, year = {2012}, abstract = {The discovery of volcanic activity on Enceladus stands out amongst the long list of findings by the Cassini mission to Saturn. In particular the compositional analysis of Enceladus ice particles by Cassini's Cosmic Dust Analyser (CDA) (Srama et al., 2004) has proven to be a powerful technique for obtaining information about processes below the moon's ice crust. Small amounts of sodium salts embedded in the particles' ice matrices provide direct evidence for a subsurface liquid water reservoir, which is, or has been, in contact with the moon's rocky core (Postberg et al., 2009, 2011b). Jupiter's Galilean satellites Ganymede, Europa, and Callisto are also believed to have subsurface oceans and are therefore prime targets for future NASA and ESA outer Solar System missions. The Galilean moons are engulfed in tenuous dust clouds consisting of tiny pieces of the moons' surfaces (Kruger et al., 1999), released by hypervelocity impacts of micrometeoroids, which steadily bombard the surfaces of the moons. In situ chemical analysis of these grains by a high resolution dust spectrometer will provide spatially resolved mapping of the surface composition of Europa. Ganymede, and Callisto, meeting key scientific objectives of the planned missions. However, novel high-resolution reflectron-type dust mass spectrometers (Sternovsky et al., 2007; Srama et al., 2007) developed for dust astronomy missions (Gran et al., 2009) are probably not robust enough to be operated in the energetic radiation environment of the inner Jovian system. In contrast, CDA's linear spectrometer is much less affected by harsh radiation conditions because its ion detector is not directly facing out into space. The instrument has been continuously operated on Cassini for 11 years. In this paper we investigate the possibility of operating a CDA-like instrument as a high resolution impact mass spectrometer. We show that such an instrument is capable of reliably identifying traces of organic and inorganic materials in the ice matrix of ejecta expected to be generated from the surfaces of the Galilean moons. These measurements are complementary, and in some cases superior, compared to other traditional techniques such as infrared remote sensing or in situ ion or neutral mass spectrometers.}, language = {en} } @article{SchmidtGeissler2011, author = {Schmidt, Bernd and Geissler, Diana}, title = {Olefin-Metathesis-Based Synthesis of Furans by an RCM/Deprotonation/Phosphorylation Sequence and Their Diels-Alder Reactions}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {35}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201101078}, pages = {7140 -- 7147}, year = {2011}, abstract = {Butenolides, obtained by ring-closing metathesis (RCM) of acrylates, undergo quantitative deprotonation with amide bases. Trapping of the resulting anions with electrophiles, for example, chlorophosphates, give furans. Subsequent DielsAlder reaction and acid-catalysed rearrangement of the resulting oxabicyclonorbornadienes give substituted benzenes.}, language = {en} } @article{SchmidtRiemerSchilde2014, author = {Schmidt, Bernd and Riemer, Martin and Schilde, Uwe}, title = {Chroman-4-ones via microwave-promoted domino claisen rearrangement-oxa-michael addition: Synthesis of tabchromones A and B}, series = {Synlett : accounts and rapid communications in synthetic organic chemistry}, volume = {25}, journal = {Synlett : accounts and rapid communications in synthetic organic chemistry}, number = {20}, publisher = {Thieme}, address = {Stuttgart}, issn = {0936-5214}, doi = {10.1055/s-0034-1379364}, pages = {2943 -- 2946}, year = {2014}, abstract = {Allyl phenyl ethers with a pendant enone substituent undergo, upon microwave irradiation, a domino sequence of Claisen rearrangement and 6-endo-trig-cyclization to furnish functionalized chroman-4-ones. The natural products tabchromones A and B were synthesized via this method.}, language = {en} } @article{SchmidtRiemer2015, author = {Schmidt, Bernd and Riemer, Martin}, title = {Synthesis of Magnaldehydes B and E and Dictyobiphenyl B by Microwave-Promoted Cross-Coupling of Boronophenols}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {17}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201500350}, pages = {3760 -- 3766}, year = {2015}, abstract = {Magnaldehydes B and E along with their 4'-methylated derivatives are naturally occurring 2,4'-biphenols that have been isolated from the Magnoliaceae. Herein, these natural products have been synthesized from a common intermediate, which was obtained by a microwave-promoted, hetero-geneously catalyzed, and protecting-group-free Suzuki-Miyaura coupling reaction in an aqueous medium. These reaction conditions were also successfully applied to a one-step synthesis of the slime mold metabolite dictyobiphenyl B.}, language = {en} } @article{SchmidtKrehlJablowski2012, author = {Schmidt, Bernd and Krehl, Stefan and Jablowski, Eric}, title = {Assisted tandem catalytic RCM-aromatization in the synthesis of pyrroles and furans}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {10}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {26}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c2ob25543j}, pages = {5119 -- 5130}, year = {2012}, abstract = {An assisted tandem catalytic transformation of diallyl amines and diallyl ethers into N-aryl pyrroles and furans, respectively, is described. The sequence relies on ring closing metathesis followed by dehydrogenation of the initially formed dihydropyrroles and dihydrofurans. Both steps are Ru-catalyzed, but the sequence requires only one precatalyst, because conversion of the metathesis catalyst into the dehydrogenation catalyst is achieved in situ, triggered by the oxidant tert-butyl hydroperoxide.}, language = {en} } @article{SchmidtElizarov2012, author = {Schmidt, Bernd and Elizarov, Nelli}, title = {Selective arene functionalization through sequential oxidative and non-oxidative Heck reactions}, series = {Chemical communications}, volume = {48}, journal = {Chemical communications}, number = {36}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1359-7345}, doi = {10.1039/c2cc30752a}, pages = {4350 -- 4352}, year = {2012}, abstract = {A sequence of acetamide directed oxidative Heck reaction and deacetylation-diazotation-Heck coupling allows the traceless removal of the acetamide group and its dual exploitation as a catalyst directing group and a leaving group.}, language = {en} } @article{SchmidtStaude2011, author = {Schmidt, Bernd and Staude, Lucia}, title = {Desymmetrization of (R,R)-Hexa-1,5-diene-3,4-diol via Monofunctionallization and Rhodium-Catalyzed Allylic Substitution}, series = {The journal of organic chemistry}, volume = {76}, journal = {The journal of organic chemistry}, number = {7}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo2001337}, pages = {2220 -- 2226}, year = {2011}, abstract = {A sequence of selective monoprotection and Rh-catalyzed enantioconservative allylic subEtitution is established as a desymmetrization strategy for C-2-symmetric hexa-1,5-diene-3,4-diol. A benzyl protecting group and ethyl carbonate as a leaving group emerged as the most useful combination with respect to reproducibility, stereoselectivity, and yield: A remarkable deviation from the normally observed regiospecificity of Rh-catalyzed allylic alkylations was observed for unprotected carbonates. In this case, a linear, rather than a branched alkylation product was obtained exclusively.}, language = {en} } @article{ReznichenkoEmgeAudoerschetal.2011, author = {Reznichenko, Alexander L. and Emge, Thomas J. and Audoersch, Stephan and Klauber, Eric G. and Hultzsch, Kai C. and Schmidt, Bernd}, title = {Group 5 metal binaphtholate complexes for catalytic asymmetric hydroaminoalkylation and hydroamination/cyclization}, series = {Organometallics}, volume = {30}, journal = {Organometallics}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0276-7333}, doi = {10.1021/om1011006}, pages = {921 -- 924}, year = {2011}, abstract = {3,3'-Silylated binaphtholate tantalum and niobium complexes were shown to be efficient catalysts for the asymmetric hydroaminoalkylation of N-methylaniline derivatives and N-benzylmethylamine with simple alkenes in enantioselectivities of up to 80\% ee. No hydroaminoalkylation was observed with aminoalkenes; rather, exclusive asymmetric hydroamination/cyclization took place in up to 81\% ee.}, language = {en} } @article{SchmidtElizarovRiemeretal.2015, author = {Schmidt, Bernd and Elizarov, Nelli and Riemer, Nastja and H{\"o}lter, Frank}, title = {Acetamidoarenediazonium Salts: Opportunities for Multiple Arene Functionalization}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {26}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201500795}, pages = {5826 -- 5841}, year = {2015}, abstract = {Unlike their ortho counterparts, meta- and para-acetamidoanilines can be converted into the corresponding acetamidoarenediazonium salts. These offer various opportunities for multiple Pd-catalyzed arene functionalization reactions, such as Matsuda-Heck-, Suzuki-Miyaura- or Fujiwara-Moritani couplings.}, language = {en} } @article{SchmidtGeissler2011, author = {Schmidt, Bernd and Geissler, Diana}, title = {Ru- and Pd-Catalysed Synthesis of 2-Arylfurans by One-Flask Heck Arylation/Oxidation}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {25}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201100549}, pages = {4814 -- 4822}, year = {2011}, abstract = {2,5-Disubstituted furans were synthesized by one-flask Heck arylation/oxidation sequences. The starting materials are 2-substituted 2,3-dihydrofurans, conveniently available by RCM/isomerization sequences, and arenediazonium salts. These react in ligand-free Heck reactions to afford 2,5-disub-stituted 2,5-dihydrofurans, which are oxidized to the corresponding furans without isolation or intermediate workup. The oxidation is conveniently achieved with chloranil or DDQ, depending on the substrate.}, language = {en} } @article{SchmidtStaudeKellingetal.2011, author = {Schmidt, Bernd and Staude, Lucia and Kelling, Alexandra and Schilde, Uwe}, title = {A Cross-Metathesis-Conjugate addition route to enantiopure gamma-Butyrolactams and gamma-Lactones from a C-2-Symmetric Precursor}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {9}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1434-193X}, doi = {10.1002/ejoc.201001528}, pages = {1721 -- 1727}, year = {2011}, abstract = {A protected derivative of (3R, 4R)-hexa-1,5-diene-3,4-diol, a conveniently accessible C-2-symmetric building block, undergoes single or double cross metathesis with methyl acryl-ate. The cross metathesis products are amenable to stereoselective conjugate addition reactions and can be converted into either gamma-butyrolactones or gamma-lactams.}, language = {en} } @article{SchmidtHauke2014, author = {Schmidt, Bernd and Hauke, Sylvia}, title = {Metathesis-Based de novo synthesis of noviose}, series = {European journal of organic chemistry}, volume = {2014}, journal = {European journal of organic chemistry}, number = {9}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201301615}, pages = {1951 -- 1960}, year = {2014}, abstract = {The rare carbohydrate L-(+)-noviose was synthesized from enantiomerically pure L-lactate. The configuration at C-4 was established by diastereoselective nucleophilic addition to an in-situ-generated lactaldehyde. The resulting homoallylic alcohol was further transformed into a set of ring-closing metathesis (RCM) precursors. These compounds were converted into noviose in few steps using RCM and RCM-allylic-oxidation sequences.}, language = {en} } @article{SchmidtHauke2013, author = {Schmidt, Bernd and Hauke, Sylvia}, title = {Cross metathesis of allyl alcohols how to suppress and how to promote double bond isomerization}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {11}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {25}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c3ob40167g}, pages = {4194 -- 4206}, year = {2013}, abstract = {Under standard conditions the cross metathesis of allyl alcohols and methyl acrylate is accompanied by the formation of ketones, resulting from uncontrolled and undesired double bond isomerization. By conducting the CM in the presence of phenol, the catalyst loading and the reaction time required for quantiative conversion can be reduced, and isomerization can be suppressed. On the other hand, consecutive isomerization can be deliberately promoted by evaporating excess methyl acrylate after completing cross metathesis and by adding a base or silane as chemical triggers.}, language = {en} } @article{SchmidtElizarovBergeretal.2013, author = {Schmidt, Bernd and Elizarov, Nelli and Berger, Ren{\´e} and Hoelter, Frank}, title = {Scope and limitations of the Heck-Matsuda-coupling of phenol diazonium salts and styrenes a protecting-group economic synthesis of phenolic stilbenes}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {11}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {22}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c3ob40420j}, pages = {3674 -- 3691}, year = {2013}, abstract = {4-Phenol diazonium salts undergo Pd-catalyzed Heck reactions with various styrenes to 4'-hydroxy stilbenes. In almost all cases higher yields and fewer side products were observed, compared to the analogous 4-methoxy benzene diazonium salts. In contrast, the reaction fails completely with 2- and 3-phenol diazonium salts. For these substitution patterns the methoxy-substituted derivatives are superior.}, language = {en} } @article{SchmidtKunzPetersen2012, author = {Schmidt, Bernd and Kunz, Oliver and Petersen, Monib H.}, title = {Total syntheses of naturally occurring seimatopolide a and its enantiomer from chiral pool starting materials using a bidirectional strategy}, series = {The journal of organic chemistry}, volume = {77}, journal = {The journal of organic chemistry}, number = {23}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo302359h}, pages = {10897 -- 10906}, year = {2012}, abstract = {Enantioselective total syntheses of both enantiomers of the recently isolated decanolide natural product seimatopolide A are described. The C-2-symmetric building blocks (R,R)-hexa-1,5-diene-3,4-diol (derived from D-mannitol) and its enantiomer (derived from L-(+)-tartrate) serve as key starting materials, which are elaborated in a bidirectional way using a selective mono-cross-metathesis, regio- and stereoselective epoxidation, and regioselective reductive epoxide opening to furnish the first fragment. Both enantiomers of the second fragment, 3-hydroxypent-4-enoic acid, were conveniently obtained through a lipase-catalyzed kinetic resolution and merged with the first fragment via Shiina esterification. An E-selective ring-closing metathesis was used to access the 10-membered lactone. A comparison of the specific optical rotations of synthetic seimatopolides with those reported for the natural product suggests that the originally assigned (3R,6R,7R,9S)-configuration should be corrected to (3S,6S,7S,9R).}, language = {en} } @article{SchmidtKunz2012, author = {Schmidt, Bernd and Kunz, Oliver}, title = {One-Flask tethered ring closing Metathesis-Electrocyclic ring opening for the highly stereoselective synthesis of conjugated Z/E-Dienes}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201101497}, pages = {1008 -- 1018}, year = {2012}, abstract = {A one-flask reaction sequence comprising ring closing metathesis (RCM) of butenoates derived from allylic alcohols and a base-mediated ring opening gives 2Z,4E-configured dienoic acids in high yields and stereoselectivities. Application of the method to the synthesis of the natural product fusanolide A suggests that the originally published structure was erroneously assigned and should be revised.}, language = {en} } @article{SchmidtHoelter2011, author = {Schmidt, Bernd and H{\"o}lter, Frank}, title = {Suzuki-Miyaura cross coupling reactions with Phenoldiazonium salts}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {9}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {13}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/c1ob05256j}, pages = {4914 -- 4920}, year = {2011}, abstract = {The Suzuki-Miyaura coupling of phenol diazonium salts and aryl trifluoroborates yields 4-hydroxybiaryls in a protecting group-free synthesis.}, language = {en} } @article{SchmidtKrehl2011, author = {Schmidt, Bernd and Krehl, Stefan}, title = {A single precatalyst tandem RCM-allylic oxidation sequence}, series = {Chemical communications}, volume = {47}, journal = {Chemical communications}, number = {20}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1359-7345}, doi = {10.1039/c1cc11347j}, pages = {5879 -- 5881}, year = {2011}, abstract = {Ring closing metathesis of allyloxy styrenes and a subsequent Ru-catalyzed allylic oxidation can be combined to a tandem sequence that makes coumarins accessible using less active but more conveniently available first generation catalysts.}, language = {en} } @article{SchmidtHaukeMuehlenberg2014, author = {Schmidt, Bernd and Hauke, Sylvia and Muehlenberg, Nino}, title = {Imino glycals via Ruthenium-catalyzed RCM and isomerization}, series = {Synthesis}, volume = {46}, journal = {Synthesis}, number = {12}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0033-1338615}, pages = {1648 -- 1658}, year = {2014}, abstract = {N-Allyl-N-homoallylamines were converted in one step into cyclic enamides via a ruthenium-catalyzed assisted tandem catalytic ring-closing metathesis-isomerization sequence. The sequence relies on the in situ transformation of a metathesis active Ru-carbene into an isomerization active Ru-hydride by addition of hydroxide as a chemical trigger.}, language = {en} } @article{SchmidtHauke2014, author = {Schmidt, Bernd and Hauke, Sylvia}, title = {Olefin cross metathesis based de novo synthesis of a partially protected L-amicetose and a fully protected L-cinerulose derivative}, series = {Beilstein journal of organic chemistry}, volume = {10}, journal = {Beilstein journal of organic chemistry}, publisher = {Beilstein-Institut zur F{\"o}rderung der Chemischen Wissenschaften}, address = {Frankfurt, Main}, issn = {1860-5397}, doi = {10.3762/bjoc.10.102}, pages = {1023 -- 1031}, year = {2014}, abstract = {Cross metathesis of a lactate derived allylic alcohol and acrolein is the entry point to a de novo synthesis of 4-benzoate protected L-amicetose and a cinerulose derivative protected at C5 and C1.}, language = {en} } @article{SchmidtRiemer2014, author = {Schmidt, Bernd and Riemer, Martin}, title = {Suzuki-Miyaura coupling of halophenols and phenol boronic acids: systematic investigation of positional isomer effects and conclusions for the synthesis of phytoalexins from Pyrinae}, series = {The journal of organic chemistry}, volume = {79}, journal = {The journal of organic chemistry}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo500675a}, pages = {4104 -- 4118}, year = {2014}, abstract = {The Suzuki-Miyaura couplings of o-, m-, and p-halophenols with o-, m-, and p-phenol boronic acids were investigated for all combinations under standardized conditions, using Pd/C as a heterogeneous catalyst and water as a solvent. In the case of iodophenols, conventional heating was used, while for bromophenols significantly better results could be obtained using microwave irradiation. This systematic study revealed that 2,4'-biphenol is particularly difficult to access, irrespective of the starting materials used, but that these difficulties can be overcome by using different additives. The conclusions drawn from this investigation allowed us to identify conditions for the protecting group-free or minimized total synthesis of biaryl-type phytoalexins. These compounds possess antibacterial activity and are produced by fruit trees as a response to microbial infection.}, language = {en} } @article{PazBecerraSilvaetal.2015, author = {Paz, Cristian and Becerra, Jose and Silva, Mario and Burgos, Viviana and Heydenreich, Matthias and Schmidt, Bernd and Thu Tran, and Vetter, Irina}, title = {(-)-Pentylsedinine, a New Alkaloid from the Leaves of Lobelia tupa with Agonist Activity at Nicotinic Acetylcholine Receptor}, series = {Natural product communications : an international journal for communications and reviews}, volume = {10}, journal = {Natural product communications : an international journal for communications and reviews}, number = {8}, publisher = {NPC}, address = {Westerville}, issn = {1934-578X}, pages = {1355 -- 1357}, year = {2015}, abstract = {Lobelia tupa, also called devil's tobacco, is a native plant from the center-south of Chile which has been used by the native people of Chile as a hallucinogenic and anesthetic plant. A new piperidine alkaloid, called pentylsedinine, which comprises five carbons in the side chain, was isolated from the aerial part of L. tupa, along with lobeline and lobelanidine. The structure was established on the basis of 1D and 2D NMR spectroscopy. While lobeline is a neutral antagonist at alpha 3 beta 2/alpha 3 beta 4 nAChR and alpha 7 nAChR, both lobelanidine and pentylsedinine act as partial agonists at nAChR}, language = {en} } @article{PazPeterSchmidtetal.2012, author = {Paz, Cristian and Peter, Martin G. and Schmidt, Bernd and Becerra, Jose and Gutierrez, Margarita and Astudillo, Luis and Silva, Mario}, title = {Synthesis and AChE inhibiting activity of 2, 4 substituted 6-Phenyl Pyrimidines}, series = {Journal of the Chilean Chemical Society}, volume = {57}, journal = {Journal of the Chilean Chemical Society}, number = {3}, publisher = {Sociedad Chilena De Quimica}, address = {Concepcion}, issn = {0717-9324}, pages = {1292 -- 1294}, year = {2012}, abstract = {Novel substituted pyrimidines were synthesized from methyl 2,4-dioxo-4-phenyl-butanoate (I-A) and urea, followed by Mitsunobu coupling of I-A with benzyl or allyl alcohol to give the corresponding 2-hydroxypyrimidine ethers in good yields. Saponification of I-A, followed by reaction with benzyl or allyl amines in the presence of TBTU yielded 2-hydroxy-6-phenyl-pyrimidine 4-carboxamides. AChE and BuChE assays revealed 2-hydroxy-6-phenyl-pyrimidine-4-carboxyallyamide as the most active compound, IC50=90 mu M, with no inhibition of BuChE.}, language = {en} } @article{SchmidtKrehlSoteloMeza2012, author = {Schmidt, Bernd and Krehl, Stefan and Sotelo-Meza, Veronica}, title = {Synthesis of chromanes through RCM-Transfer hydrogenation}, series = {Synthesis}, volume = {44}, journal = {Synthesis}, number = {11}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0031-1289758}, pages = {1603 -- 1613}, year = {2012}, abstract = {A sequential ruthenium-catalyzed ring-closing metathesis-transfer hydrogenation sequence has been established as a synthesis of chromanes starting from 2-(allyloxy)styrenes. The sequence requires only one precatalyst, the first-generation Grubbs catalyst, which is converted into a ruthenium hydride species in situ. Propan-2-ol serves as a chemical trigger for the formation of the ruthenium hydride and as hydrogen source.}, language = {en} } @article{SchmidtRiemerSchilde2015, author = {Schmidt, Bernd and Riemer, Martin and Schilde, Uwe}, title = {Tandem Claisen Rearrangement/6-endo Cyclization Approach to Allylated and Prenylated Chromones}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {34}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201501151}, pages = {7602 -- 7611}, year = {2015}, abstract = {Allyl, dimethylallyl and prenyl ethers derived from o-acyl-phenols reacted upon microwave irradiation to form C-allylated or -prenylated chromone derivatives, depending on the substitution pattern of the arene and the allyl substituent. The reaction proceeds through a tandem Claisen rearrangement and 6-endo-trig or 6-endo-dig cyclization sequence. For prenyl ethers, the tandem sequence can be extended by a Cope rearrangement to furnish 6-prenylchromones. The method is potentially useful for the synthesis of natural products and drugs.}, language = {en} } @article{SchmidtRiemer2016, author = {Schmidt, Bernd and Riemer, Martin}, title = {Microwave-Promoted Deprenylation: Prenyl Ether as a Thermolabile Phenol Protecting Group}, series = {Synthesis}, volume = {48}, journal = {Synthesis}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0035-1561366}, pages = {1399 -- 1406}, year = {2016}, abstract = {para-Substituted aryl prenyl ethers undergo a deprenylation reaction upon microwave irradiation. This offers the opportunity to use a prenyl ether as a thermolabile protecting group in the synthesis of natural products with a chromone structure, which proceeds via a tandem deprenylation/6-endo-cyclization sequence.}, language = {en} } @article{SchmidtAudoerschKunz2016, author = {Schmidt, Bernd and Audoersch, Stephan and Kunz, Oliver}, title = {Stereoselective Synthesis of 2Z,4E-Configured Dienoates through Tethered Ring Closing Metathesis}, series = {Synthesis}, volume = {48}, journal = {Synthesis}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0035-1562536}, pages = {4509 -- 4518}, year = {2016}, language = {en} } @article{SchmidtWolfEhlert2016, author = {Schmidt, Bernd and Wolf, Felix and Ehlert, Christopher}, title = {Systematic Investigation into the Matsuda-Heck Reaction of alpha-Methylene Lactones: How Conformational Constraints Direct the beta-H-Elimination Step}, series = {The journal of organic chemistry}, volume = {81}, journal = {The journal of organic chemistry}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.6b02207}, pages = {11235 -- 11249}, year = {2016}, abstract = {alpha-Methylene-gamma-butyrolactone and alpha-methylene-gamma-valerolactone undergo Pd-catalyzed Matsuda-Heck couplings with arene diazonium salts to alpha-benzyl butenolides or pentenolides, respectively, or to alpha-benzylidene lactones. The observed regioselectivity is strongly ring size dependent, with six-membered rings giving exclusively alpha-benzyl pentenolides, whereas the five-membered alpha-methylene lactone reacts to mixtures of regioisomers with a high proportion of (E)-alpha-benzylidene-gamma-butyrolactones. DFT calculations suggest that the reasons for these differences are not thermodynamic but kinetic in nature. The relative energies of the conformers of the Pd sigma-complexes resulting from insertion into the Pd-aryl bond were correlated with the dihedral angles between Pd and endo-beta-H. This correlation revealed that in the case of the six-membered lactone an energetically favorable conformer adopts a nearly synperiplanar Pd/endo-beta-H arrangement, whereas for the analogous Pd sigma-complex of the five-membered lactone the smallest Pd/endo-beta-H dihedral angle is observed for a conformer with a comparatively high potential energy. The optimized conditions for Matsuda-Heck arylations of exo-methylene lactones were eventually applied to the synthesis of the natural product anemarcoumarin A.}, language = {en} } @article{SchmidtWolfBrunner2016, author = {Schmidt, Bernd and Wolf, Felix and Brunner, Heiko}, title = {Styrylsulfonates and -Sulfonamides through Pd-Catalysed Matsuda-Heck Reactions of Vinylsulfonic Acid Derivatives and Arenediazonium Salts}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201600469}, pages = {2972 -- 2982}, year = {2016}, abstract = {Arene diazonium salts undergo Matsuda-Heck reactions with vinylsulfonates and -sulfonamides to give styrylsulfonic acid derivatives in high to excellent yields and with high to excellent selectivities. By quantifying the evolution of nitrogen over time in a gas-meter apparatus, the reactivities of ethylvinylsulfonate and the benchmark olefin methyl acrylate were compared for an electron-rich and an -deficient arene diazonium salt. Tertiary sulfonamides react in Matsuda-Heck couplings with high conversions, but require long reaction times, which prevents the determination of kinetic data through the measurement of nitrogen evolution. Secondary sulfonamides were found to be unreactive. From these results, the following order of reactivity could be deduced: H2C=CHCO2Me > H2C=CHSO2OEt > H2C=CHSO2N(Me)Bn >> H2C=CHSO2NHBn. Through the Matsuda-Heck coupling of 5-indolyldiazonium salt and a tertiary vinylsulfonamide, the synthesis of the C-5-substituted indole part of the antimigraine drug naratriptan was accomplished in high yield.}, language = {en} } @article{PazBecerraSilvaetal.2016, author = {Paz, Cristian and Becerra, Jose and Silva, Mario and Cabrera-Pardo, Jaime and Burgos, Viviana and Heydenreich, Matthias and Schmidt, Bernd}, title = {(-)-8-Oxohobartine a New Indole Alkaloid from Aristotelia chilensis (Mol.) Stuntz}, series = {Records of Natural Products}, volume = {10}, journal = {Records of Natural Products}, publisher = {ACG Publications}, address = {Gebze-Kocaeli}, issn = {1307-6167}, pages = {68 -- 73}, year = {2016}, abstract = {The fruit of Aristotelia chilensis is considered a "super fruit" due to its high concentration of polyphenols displaying exceptional antioxidant capacities ORAC. From maqui berries have been reported several anthocyanins and glycosylated flavonoids, those benefits increase the attention to restudy the plant. From the leaves of A. chilensis several indole alkaloids have been reported, we in addition to aristoteline, aristone, aristoquinoline and 3-fromylindole report the spectroscopic elucidation of 8-oxo-9-dehydromakomakine (1), hobartine (2) and a new alkaloid named 8-oxohobartine (3). Compound 1 to 3 did not show bactericidal activity against E. coli and S. aureus till 200 mu g.}, language = {en} } @article{SchmidtRiemer2016, author = {Schmidt, Bernd and Riemer, Martin}, title = {Synthesis of Allyl- and Prenylcoumarins via Microwave-Promoted Tandem Claisen Rearrangement/Wittig Olefination}, series = {Synthesis}, volume = {48}, journal = {Synthesis}, publisher = {Thieme}, address = {Stuttgart}, issn = {0039-7881}, doi = {10.1055/s-0035-1560501}, pages = {141 -- 149}, year = {2016}, abstract = {Allyl, dimethylallyl, crotyl, and prenyl ethers of various aromatic ortho-hydroxy carbonyl compounds undergo a tandem sequence of Claisen rearrangement, carbonyl olefination, and cyclization upon microwave irradiation in the presence of a stabilized ylide. The products are multiply substituted 6- or 8-allylated or prenylated coumarins (2H-chromen-2-ones).}, language = {en} } @article{SchmidtStaude2006, author = {Schmidt, Bernd and Staude, Lucia}, title = {Unexpected transfer hydrogenation of C-C-double bonds during Tandem-RCM-isomerization reactions}, series = {Journal of organometallic chemistry}, volume = {691}, journal = {Journal of organometallic chemistry}, number = {24-25}, publisher = {Elsevier}, address = {Lausanne}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2006.07.011}, pages = {5218 -- 5221}, year = {2006}, abstract = {Unexpected hydrogen transfer from 2-propanol to C-C-double bonds has been observed in the course of a Tandem RCM-isomerization reaction leading to sterically congested spirocycles.}, language = {en} } @article{SchmidtWolf2017, author = {Schmidt, Bernd and Wolf, Felix}, title = {Synthesis of Phenylpropanoids via Matsuda-Heck Coupling of Arene Diazonium Salts}, series = {The journal of organic chemistry}, volume = {82}, journal = {The journal of organic chemistry}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.7b00447}, pages = {4386 -- 4395}, year = {2017}, abstract = {The Pd-catalyzed Heck-type coupling (Matsuda Heck reaction) of electron rich arene diazonium salts with electron deficient olefins has been exploited for the synthesis of phenylpropanoid natural products. Examples described herein are the naturally occurring benzofurans methyl wutaifuranate, wutaifuranol, wutaifuranal, their 7-methoxy derivatives, and the O-prenylated natural products boropinols A and C.}, language = {en} } @article{SchmidtHermanns2006, author = {Schmidt, Bernd and Hermanns, Jolanda}, title = {Ring closing metathesis of substrates containing more than two C-C-double bonds : rapid access to functionalized heterocycles}, year = {2006}, abstract = {In most cases where ring closing metathesis is applied to the synthesis of heterocycles, alpha,omega-dienes are used as precursors. If substrates containing more than two double bonds are subjected to a metathesis reaction, carba- or heterocycles bearing additional exocyclic alkene functionality result, or multiple ring closing processes occur. This offers interesting and potentially very useful synthetic perspectives. On the other hand, selectivity problems need to be addressed as the cyclization of substrates with more than two double bonds available for olefin metathesis may result in constitutional isomers or stereoisomers. This review highlights problems and opportunities evolving from ring closing metathesis of tri-, tetra-, and polyenes as a strategy for the selective synthesis of functionalized heterocycles. The chapter on RCM of trienes is subdivided according to the symmetry of the metathesis precursor. The following two chapters deal with the double or multiple RCM of tetra- or polyenes. These processes are further classified according to the preferred cyclization mode. Finally, the application of cascade or domino metathesis reactions to the synthesis of heterocycles will be discussed. These processes can be classified into those where exclusively C-C-double bonds take part in the metathesis reaction, and those where one or more C-C-triple bonds are involved}, language = {en} } @article{HermannsSchmidt2017, author = {Hermanns, Jolanda and Schmidt, Bernd}, title = {Zur Verwendung von QR-Codes in Uni-Seminaren - ein Baustein in den neu konzipierten {\"U}bungen zur Vorlesung „Organische Chemie f{\"u}r Studierende im Nebenfach"}, series = {Chemkon}, volume = {24}, journal = {Chemkon}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0944-5846}, doi = {10.1002/ckon.201710300}, pages = {139 -- 141}, year = {2017}, abstract = {Die Verwendung von QR-Codes in Begleitseminaren zur Vorlesung „Organische Chemie" f{\"u}r Studierende mit Chemie im Nebenfach wird vorgestellt. Die Hausaufgaben zu den Seminaren wurden mit einem QR-Code versehen. Dieser f{\"u}hrt zu weiterf{\"u}hrenden Hilfen. Der Einsatz der QR-Codes sowie die Neukonzeption der Seminare wurden evaluiert.}, language = {de} } @article{AriasFeuerbachSchmidtetal.2018, author = {Arias, Hugo R. and Feuerbach, Dominik and Schmidt, Bernd and Heydenreich, Matthias and Paz, Cristian and Ortells, Marcelo O.}, title = {Drimane Sesquiterpenoids Noncompetitively Inhibit Human alpha 4 beta 2 Nicotinic Acetylcholine Receptors with Higher Potency Compared to Human alpha 3 beta 4 and alpha 7 Subtypes}, series = {Journal of natural products}, volume = {81}, journal = {Journal of natural products}, number = {4}, publisher = {American Chemical Society}, address = {Washington}, issn = {0163-3864}, doi = {10.1021/acs.jnatprod.7b00893}, pages = {811 -- 817}, year = {2018}, abstract = {The drimane sesquiterpenoids drimenin, cinnamolide, dendocarbin A, and polygodial were purified from the Canelo tree (Drimys winteri) and chemically characterized by spectroscopic methods. The pharmacological activity of these natural compounds were determined on hα4β2, hα3β4, and hα7 nicotinic acetylcholine receptors (AChRs) by Ca2+ influx measurements. The results established that drimane sesquiterpenoids inhibit AChRs with the following selectivity: hα4β2 > hα3β4 > hα7. In the case of hα4β2 AChRs, the following potency rank order was determined (IC50's in μM): drimenin (0.97 ± 0.35) > cinnamolide (1.57 ± 0.36) > polygodial (62.5 ± 19.9) ≫ dendocarbin A (no activity). To determine putative structural features underlying the differences in inhibitory potency at hα4β2 AChRs, additional structure-activity relationship and molecular docking experiments were performed. The Ca2+ influx and structural results supported a noncompetitive mechanism of inhibition, where drimenin interacted with luminal and nonluminal (TMD-β2 intrasubunit) sites. The structure-activity relationship results, i.e., the lower the ligand polarity, the higher the inhibitory potency, supported the nonluminal interaction. Ligand binding to both sites might inhibit the hα4β2 AChR by a cooperative mechanism, as shown experimentally (nH > 1). Drimenin could be used as a molecular scaffold for the development of more potent inhibitors with higher selectivity for the hα4β2 AChR.}, language = {en} } @article{SchmidtAudoersch2017, author = {Schmidt, Bernd and Aud{\"o}rsch, Stephan}, title = {Stereoselective Total Syntheses of Polyacetylene Plant Metabolites via Ester-Tethered Ring Closing Metathesis}, series = {The journal of organic chemistry}, volume = {82}, journal = {The journal of organic chemistry}, number = {3}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.6b02987}, pages = {1743 -- 1760}, year = {2017}, abstract = {Total syntheses of five naturally occurring polyacetylenes from three different plants are described. These natural products have in common an E,Z-configured conjugated diene linked to a di-or triyne chain. As the key method to stereoselectively establish the E,Z-diene part, an ester-tethered ring-closing metathesis/base-induced eliminative ring opening sequence was used. The results presented herein do not only showcase the utility of this tethered RCM variant but have also prompted us to suggest that the originally assigned absolute configurations of chiral polyacetylenes from Atractylodes macrocephala should be revised or at least reconsidered.}, language = {en} } @article{KrauseSperlichSchmidt2021, author = {Krause, Andreas and Sperlich, Eric and Schmidt, Bernd}, title = {Matsuda-Heck arylation of itaconates}, series = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, volume = {19}, journal = {Organic \& biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry}, number = {19}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-0520}, doi = {10.1039/d1ob00392e}, pages = {4292 -- 4302}, year = {2021}, abstract = {Itaconic acid esters and hemiesters undergo Pd-catalyzed coupling reactions with arene diazonium salts in high to excellent yields. The coupling products of ortho-nitro arene diazonium salts can be converted in one or two steps to benzazepine-2-ones.}, language = {en} } @article{SchmidtRiemer2017, author = {Schmidt, Bernd and Riemer, Martin}, title = {Microwave-Promoted Pd-Catalyzed Synthesis of Dibenzofurans from Ortho-Arylphenols}, series = {Journal of Heterocyclic Chemistry}, volume = {54}, journal = {Journal of Heterocyclic Chemistry}, number = {2}, publisher = {Wiley}, address = {Hoboken}, issn = {0022-152X}, doi = {10.1002/jhet.2704}, pages = {1287 -- 1297}, year = {2017}, abstract = {ortho-Aryl phenols, synthesized via protecting group free Suzuki-Miyaura coupling of ortho-halophenols and arene boronic acids, undergo a cyclization to dibenzofurans via oxidative C-H activation. The reaction proceeds under microwave irradiation in short reaction times using catalytic amounts of Pd(OAc)(2) without additional ligands.}, language = {en} } @article{BehrendtHessLehmannetal.2019, author = {Behrendt, Felix Nicolas and Hess, Andreas and Lehmann, Max and Schmidt, Bernd and Schlaad, Helmut}, title = {Polymerization of cystine-derived monomers}, series = {Polymer Chemistry}, volume = {10}, journal = {Polymer Chemistry}, number = {13}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1759-9954}, doi = {10.1039/c9py00118b}, pages = {1636 -- 1641}, year = {2019}, abstract = {Cystine was used as a platform chemical to prepare cyclic and acyclic monomers for entropy-driven ringopening polymerization (ED-ROMP) via olefin or disulfide metathesis and for step-growth polymerization. The olefin ED-ROMP of an olefin/disulfide containing 16-atom macrocycle using the 3rd generation Grubbs catalyst was examined in greater detail. Kinetic studies revealed that the catalyst turned inactive during the polymerization, which limited the achievable (apparent) polymer molar mass to similar to 70 kg mol(-1). Such limitation could be overcome with the disulfide ED-ROMP of the same macrocycle to yield polymers with molar masses of up to 180 kg mol(-1). The step-growth polymerizations of acyclic diene and dithiol monomers via olefin metathesis or oxidation were far less effective and yielded just low molar mass polymers or oligomers; photopolymerization of a thiol-ene monomer produced a polyester with a molar mass of 35 kg mol(-1).}, language = {en} } @article{ToetzkeMankeGaiselmannetal.2015, author = {T{\"o}tzke, Christian and Manke, Ingo and Gaiselmann, Gerd and Bohner, John and M{\"u}ller, Bernd R. and Kupsch, Andreas and Hentschel, Manfred P. and Schmidt, Volker and Banhart, Jens and Lehnert, Werner}, title = {A dedicated compression device for high resolution X-ray tomography of compressed gas diffusion layers}, series = {Review of scientific instruments : a monthly journal devoted to scientific instruments, apparatus, and techniques}, volume = {86}, journal = {Review of scientific instruments : a monthly journal devoted to scientific instruments, apparatus, and techniques}, number = {4}, publisher = {American Institute of Physics}, address = {Melville}, issn = {0034-6748}, doi = {10.1063/1.4918291}, pages = {6}, year = {2015}, abstract = {We present an experimental approach to study the three-dimensional microstructure of gas diffusion layer (GDL) materials under realistic compression conditions. A dedicated compression device was designed that allows for synchrotron-tomographic investigation of circular samples under well-defined compression conditions. The tomographic data provide the experimental basis for stochastic modeling of nonwoven GDL materials. A plain compression tool is used to study the fiber courses in the material at different compression stages. Transport relevant geometrical parameters, such as porosity, pore size, and tortuosity distributions, are exemplarily evaluated for a GDL sample in the uncompressed state and for a compression of 30 vol.\%. To mimic the geometry of the flow-field, we employed a compression punch with an integrated channel-rib-profile. It turned out that the GDL material is homogeneously compressed under the ribs, however, much less compressed underneath the channel. GDL fibers extend far into the channel volume where they might interfere with the convective gas transport and the removal of liquid water from the cell. (C) 2015 AIP Publishing LLC.}, language = {en} } @misc{SchroederGrimmSchulzetal.2017, author = {Schr{\"o}der, Astrid and Grimm, Angela and Schulz, Petra and Heide, Judith and Frank, Ulrike and Wahl, Michael and Lampe, Leonie and Fieder, Nora and Krajenbrink, Trudy and Nickels, Lyndsey and Bykova, Ksenia and Wilzek, Alexa and van den Engl-Hoek, Lenie and Huckabee, Maggie-Lee and Balzer, Julia and Ebert, Susanne and Kaps, Hella and Matteschk, Maria and Tzsch{\"o}ckel, Katharina Andrea and Dressel, Katharina and Kr{\"o}ger, Bernd J. and Diwoky, Laura Cassandra and Breitenstein, Sarah and Bruno, Giulia and Lassotta, Romy and Adani, Flavia and Ferchland, Lisa and Baatz, Charlotte and Netzebandt, Jonka and Heyde, Cornelia J. and Cleland, Joanne and Scobbie, James M. and Roxburgh, Zoe and Schmidt, Jessica}, title = {Spektrum Patholinguistik Band 10. Schwerpunktthema: Panorama Patholinguistik: Sprachwissenschaft trifft Sprachtherapie}, number = {10}, editor = {Adelt, Anne and Yetim, {\"O}zlem and Otto, Constanze and Fritzsche, Tom}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, organization = {Verband f{\"u}r Patholinguistik e. V. (vpl)}, isbn = {978-3-86956-404-3}, issn = {1866-9085}, doi = {10.25932/publishup-39701}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-397019}, pages = {vii, 225 S.}, year = {2017}, abstract = {Das 10. Herbsttreffen Patholinguistik mit dem Schwerpunktthema »Panorama Patholinguistik: Sprachwissenschaft trifft Sprachtherapie« fand am 19.11.2016 in Potsdam statt. Das Herbsttreffen wird seit 2007 j{\"a}hrlich vom Verband f{\"u}r Patholinguistik e.V. (vpl) durchgef{\"u}hrt. Der vorliegende Tagungsband beinhaltet die vier Hauptvortr{\"a}ge zum Schwerpunktthema sowie Beitr{\"a}ge zu den Kurzvortr{\"a}gen »Patholinguistik im Fokus« und der Posterpr{\"a}sentationen zu weiteren Themen aus der sprachtherapeutischen Forschung und Praxis.}, language = {de} }