@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{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{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} } @article{DebsharmaSchmidtLaschewskyetal.2021, author = {Debsharma, Tapas and Schmidt, Bernd and Laschewsky, Andre and Schlaad, Helmut}, title = {Ring-opening metathesis polymerization of unsaturated carbohydrate derivatives}, series = {Macromolecules : a publication of the American Chemical Society}, volume = {54}, journal = {Macromolecules : a publication of the American Chemical Society}, number = {6}, publisher = {American Chemical Society}, address = {Washington}, issn = {0024-9297}, doi = {10.1021/acs.macromol.0c02821}, pages = {2720 -- 2728}, year = {2021}, abstract = {A series of biomass-derived levoglucosenyl alkyl ethers (alkyl = methyl, ethyl, n-propyl, isopropyl, and n-butyl) were synthesized and polymerized by ring-opening olefin metathesis polymerization using the Grubbs catalyst C793 at room temperature. Polymerizations were successfully performed in conventional solvents such as 1,4-dioxane and dichloromethane as well as in polar aprotic "green" solvents such as 2-methyltetrahydrofuran, dihydrolevoglucosenone (Cyrene), and ethyl acetate. The prepared polyacetals with degrees of polymerization of similar to 100 exhibit Schulz-Flory-type molar mass distributions and are thermoplastic materials with rather low glass transition temperatures in the range of 43-0 degrees C depending on the length of the alkyl substituent. Kinetic studies revealed that the polymerization proceeded rapidly to a steady state with a certain minimum monomer concentration threshold. When the steady state was reached, just about half of the [Ru] catalyst had been effective to initiate the polymerization, indicating that the initiation step was a slow process. The remaining catalyst was still active and did no longer react with monomers but with in-chain double bonds, cutting the formed polymer chains into shorter fragments. In the long term, all catalyst was consumed and propagating [Ru] chain ends were deactivated by the elimination of [Ru] from the chain ends to form inactive chains with terminal aldehyde groups.}, language = {en} } @misc{MangelsdorfHornConradBagdahnetal.2011, author = {Mangelsdorf, Birgit and Horn-Conrad, Antje and Bagdahn, Christian and Schmidt, Bernd and Eckardt, Barbara and G{\"o}rlich, Petra and Peter, Andreas and P{\"o}sl, Thomas and Nestler, Ralf and Zimmermann, Matthias}, title = {Portal = Wenn die Chemie stimmt: L{\"o}sungen f{\"u}r heute und morgen}, series = {Das Potsdamer Universit{\"a}tsmagazin}, journal = {Das Potsdamer Universit{\"a}tsmagazin}, number = {03/2011}, organization = {Universit{\"a}t Potsdam, Referat f{\"u}r Presse- und {\"O}ffentlichkeitsarbeit}, issn = {1618-6893}, doi = {10.25932/publishup-45981}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459810}, pages = {43}, year = {2011}, abstract = {Aus dem Inhalt: - Wenn die Chemie stimmt: L{\"o}sungen f{\"u}r heute und morgen - Das Kreuz mit dem Kreuz - „Das verr{\"u}ckteste Jahr unseres Lebens"}, language = {de} } @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} }