TY - JOUR A1 - Nchiozem-Ngnitedem, Vaderament-Alexe A1 - Sperlich, Eric A1 - Matieta, Valaire Yemene A1 - Kuete, Jenifer Reine Ngnouzouba A1 - Kuete, Victor A1 - Omer, Ejlal A. A. A1 - Efferth, Thomas A1 - Schmidt, Bernd T1 - Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues JF - Journal of natural products : Lloydia N2 - FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold. KW - Antimicrobial activity KW - Bacteria KW - Ethers KW - Flavonoids KW - Mixtures Y1 - 2023 U6 - https://doi.org/10.1021/acs.jnatprod.3c00219 SN - 0163-3864 SN - 1520-6025 VL - 86 IS - 6 SP - 1520 EP - 1528 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Zhao, Yuhang A1 - Sarhan, Radwan Mohamed A1 - Eljarrat, Alberto A1 - Kochovski, Zdravko A1 - Koch, Christoph A1 - Schmidt, Bernd A1 - Koopman, Wouter-Willem Adriaan A1 - Lu, Yan T1 - Surface-functionalized Au-Pd nanorods with enhanced photothermal conversion and catalytic performance JF - ACS applied materials & interfaces N2 - Bimetallic nanostructures comprising plasmonic and catalytic components have recently emerged as a promising approach to generate a new type of photo-enhanced nanoreactors. Most designs however concentrate on plasmon-induced charge separation, leaving photo-generated heat as a side product. This work presents a photoreactor based on Au-Pd nanorods with an optimized photothermal conversion, which aims to effectively utilize the photo-generated heat to increase the rate of Pd-catalyzed reactions. Dumbbell-shaped Au nanorods were fabricated via a seed-mediated growth method using binary surfactants. Pd clusters were selectively grown at the tips of the Au nanorods, using the zeta potential as a new synthetic parameter to indicate the surfactant remaining on the nanorod surface. The photothermal conversion of the Au-Pd nanorods was improved with a thin layer of polydopamine (PDA) or TiO2. As a result, a 60% higher temperature increment of the dispersion compared to that for bare Au rods at the same light intensity and particle density could be achieved. The catalytic performance of the coated particles was then tested using the reduction of 4-nitrophenol as the model reaction. Under light, the PDA-coated Au-Pd nanorods exhibited an improved catalytic activity, increasing the reaction rate by a factor 3. An analysis of the activation energy confirmed the photoheating effect to be the dominant mechanism accelerating the reaction. Thus, the increased photothermal heating is responsible for the reaction acceleration. Interestingly, the same analysis shows a roughly 10% higher reaction rate for particles under illumination compared to under dark heating, possibly implying a crucial role of localized heat gradients at the particle surface. Finally, the coating thickness was identified as an essential parameter determining the photothermal conversion efficiency and the reaction acceleration. KW - Au-Pd nanorods KW - PDA KW - photothermal conversion KW - surface plasmon KW - 4-nitrophenol Y1 - 2022 U6 - https://doi.org/10.1021/acsami.2c00221 SN - 1944-8244 SN - 1944-8252 VL - 14 IS - 15 SP - 17259 EP - 17272 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Riemer, Nastja A1 - Riemer, Martin A1 - Krüger, Mandy A1 - Clarkson, Guy J. A1 - Shipman, Michael A1 - Schmidt, Bernd T1 - Synthesis of arylidene-beta-lactams via exo-selective Matsuda-Heck arylation of methylene-beta-lactams JF - The journal of organic chemistry : JOC N2 - exo-Methylene-beta-lactams were synthesized in two steps from commercially available 3-bromo-2-(bromomethyl)-propionic acid and reacted with arene diazonium salts in a Heck-type arylation in the presence of catalytic amounts of Pd(OAc)(2) under ligand-free conditions. The products, arylidene-beta-lactams, were obtained in high yields as single isomers. The beta-hydride elimination step of the Pd-catalyzed coupling reaction proceeds with high exo-regioselectivity and E-stereoselectivity. With aryl iodides, triflates, or bromides, the coupling products were isolated only in low yields, due to extensive decomposition of the starting material at elevated temperatures. This underlines that arene diazonium salts can be superior arylating reagents in Heck-type reactions and yield coupling products in synthetically useful yields and selectivities when conventional conditions fail. Y1 - 2021 U6 - https://doi.org/10.1021/acs.joc.1c00638 SN - 0022-3263 SN - 1520-6904 VL - 86 IS - 13 SP - 8786 EP - 8796 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Oloya, Benson A1 - Namukobe, Jane A1 - Heydenreich, Matthias A1 - Ssengooba, Willy A1 - Schmidt, Bernd A1 - Byamukama, Robert T1 - Antimycobacterial activity of the extract and isolated compounds from the stem bark of Zanthoxylum leprieurii Guill. and Perr. JF - Natural product communications : an international journal for communications and reviews N2 - Zanthoxylum leprieurii Guill. and Perr. (Rutaceae) stem bark is used locally in Uganda for treating tuberculosis (TB) and cough-related infections. Lupeol (1), sesamin (2), trans-fagaramide (3), arnottianamide (4), (S)-marmesinin (5), and hesperidin (6) were isolated from the chloroform/methanol (1:1) extract of Z. leprieurii stem bark. Their structures were elucidated using spectroscopic techniques and by comparison with literature data. Furthermore, the extract and isolated compounds were subjected to antimycobacterial activity. The extract exhibited moderate activity against the susceptible (H(37)Rv) TB strain, but weak activity against the multidrug resistant (MDR)-TB strain with minimum inhibitory concentrations (MICs) of 586.0 and 1172.0 mu g/mL, respectively. Compound 3 (trans-fagaramide) showed significant antimycobacterial activity against the susceptible (H(37)Rv) TB strain (MIC 6 mu g/mL), but moderate activity against the MDR-TB strain (MIC 12.2 mu g/mL). Compounds 2, 5, 6, and 1 showed moderate activities against the susceptible (H(37)Rv) strain (MIC 12.2-98.0 mu g/mL) and moderate to weak activities against the MDR-TB strain (MIC 24.4-195.0 mu g/mL). This study reports for the first time the isolation of compounds 1 to 6 from the stem bark of Z leprieurii. trans-Fagaramide (3) may present a vital template in pursuit of novel and highly effective TB drugs. KW - tuberculosis KW - Zanthoxylum leprieurii KW - antimycobacterial activity KW - trans-fagaramide KW - alkaloid Y1 - 2021 U6 - https://doi.org/10.1177/1934578X211035851 SN - 1934-578X SN - 1555-9475 VL - 16 IS - 8 PB - Sage Publ. CY - Thousand Oaks ER - TY - JOUR A1 - Debsharma, Tapas A1 - Schmidt, Bernd A1 - Laschewsky, Andre A1 - Schlaad, Helmut T1 - Ring-opening metathesis polymerization of unsaturated carbohydrate derivatives BT - levoglucosenyl alkyl ethers JF - Macromolecules : a publication of the American Chemical Society N2 - 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. Y1 - 2021 U6 - https://doi.org/10.1021/acs.macromol.0c02821 SN - 0024-9297 SN - 1520-5835 VL - 54 IS - 6 SP - 2720 EP - 2728 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Lohwaßer, Roswitha A1 - Musil, Andreas A1 - van Kempen, Britta A1 - Schubarth, Wilfried A1 - Wendland, Mirko A1 - Burchard, Daniel A1 - Reimann, Margit A1 - Pohlmann, Markus A1 - Mauermeister, Sylvi A1 - Fenn, Monika A1 - Schmidt, Bernd A1 - Lukowski, Sarah A1 - Borowski, Andreas T1 - Kentron : Journal zur Lehrerbildung = UPgrade Lehrerbildung T3 - Kentron : Journal zur Lehrerbildung - 33 Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-590400 SN - 1867-4720 SN - 1867-4747 IS - 33 PB - Universität Potsdam, Zentrum für Lehrerbildung CY - Potsdam ER - TY - JOUR A1 - Kwesiga, George A1 - Kelling, Alexandra A1 - Kersting, Sebastian A1 - Sperlich, Eric A1 - von Nickisch-Rosenegk, Markus A1 - Schmidt, Bernd T1 - Total syntheses of prenylated isoflavones from Erythrina sacleuxii and their antibacterial activity BT - 5-deoxy-3′-prenylbiochanin A and erysubin F JF - Journal of natural products N2 - The prenylated isoflavones 5-deoxyprenylbiochanin A (7-hydroxy-4'-methoxy-3'-prenylisoflavone) and erysubin F (7,4'-dihydroxy-8,3'-diprenylisoflavone) were synthesized for the first time, starting from mono-or di-O-allylated chalcones, and the structure of 5-deoxy-3'-prenylbiochanin A was corroborated by single-crystal X-ray diffraction analysis. Flavanones are key intermediates in the synthesis. Their reaction with hypervalent iodine reagents affords isoflavones via a 2,3-oxidative rearrangement and the corresponding flavone isomers via 2,3-dehydrogenation. This enabled a synthesis of 7,4'-dihydroxy-8,3'-diprenylflavone, a non-natural regioisomer of erysubin F. Erysubin F (8), 7,4'-dihydroxy-8,3'-diprenylflavone (27), and 5-deoxy-3'prenylbiochanin A (7) were tested against three bacterial strains and one fungal pathogen. All three compounds are inactive against Salmonella enterica subsp. enterica (NCTC 13349), Escherichia coli (ATCC 25922), and Candida albicans (ATCC 90028), with MIC values greater than 80.0 mu M. The diprenylated natural product erysubin F (8) and its flavone isomer 7,4'-dihydroxy-8,3'diprenylflavone (27) show in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA, ATCC 43300) at MIC values of 15.4 and 20.5 mu M, respectively. In contrast, the monoprenylated 5-deoxy-3'-prenylbiochanin A (7) is inactive against this MRSA strain. Y1 - 2020 U6 - https://doi.org/10.1021/acs.jnatprod.0c00932 SN - 0163-3864 SN - 1520-6025 VL - 83 IS - 11 SP - 3445 EP - 3453 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Lood, Kajsa A1 - Tikk, Triin A1 - Krüger, Mandy A1 - Schmidt, Bernd T1 - Methylene capping facilitates cross-metathesis reactions of enals BT - a short synthesis of 7-methoxywutaifuranal from the xylochemical isoeugenol JF - The journal of organic chemistry N2 - 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. KW - Aldehydes KW - Catalysts KW - Hydrocarbons KW - Metathesis KW - Mixtures Y1 - 2022 U6 - https://doi.org/10.1021/acs.joc.1c02851 SN - 0022-3263 SN - 1520-6904 VL - 87 IS - 5 SP - 3079 EP - 3088 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Krause, Andreas A1 - Sperlich, Eric A1 - Schmidt, Bernd T1 - Matsuda-Heck arylation of itaconates BT - a versatile approach to heterocycles from a renewable resource JF - Organic & biomolecular chemistry : an international journal of synthetic, physical and biomolecular organic chemistry N2 - 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. Y1 - 2021 U6 - https://doi.org/10.1039/d1ob00392e SN - 1477-0520 SN - 1477-0539 VL - 19 IS - 19 SP - 4292 EP - 4302 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Hermanns, Jolanda A1 - Schmidt, Bernd A1 - Glowinski, Ingrid A1 - Keller, David T1 - Online teaching in the course "organic chemistry" for nonmajor chemistry students BT - from necessity to opportunity JF - Journal of chemical education N2 - 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. KW - first-year undergraduate/general KW - organic chenlistry KW - computer-based KW - learning KW - distance learning/self instruction Y1 - 2020 U6 - https://doi.org/10.1021/acs.jchemed.0c00658 SN - 0021-9584 SN - 1938-1328 VL - 97 IS - 9 SP - 3140 EP - 3146 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Lood, Kajsa A1 - Schmidt, Bernd T1 - Stereoselective synthesis of conjugated polyenes based on tethered olefin metathesis and carbonyl olefination BT - application to the total synthesis of (+)-bretonin B JF - The journal of organic chemistry N2 - 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. KW - absolute-configuration KW - natural-products KW - formal synthesis KW - oxidation KW - derivatives KW - aldehydes KW - catalysts KW - alcohols KW - sponge KW - ethers Y1 - 2020 U6 - https://doi.org/10.1021/acs.joc.0c00446 SN - 0022-3263 SN - 1520-6904 VL - 85 IS - 7 SP - 5122 EP - 5130 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Schultze, Christiane A1 - Foß, Stefan A1 - Schmidt, Bernd T1 - 8-Prenylflavanones through microwave promoted tandem claisen rearrangement/6-endo-trig cyclization and cross metathesis JF - European journal of organic chemistry N2 - 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. KW - tandem reactions KW - arenes KW - oxygen heterocycles KW - microwave chemistry KW - rearrangement Y1 - 2020 U6 - https://doi.org/10.1002/ejoc.202001378 SN - 1434-193X SN - 1099-0690 VL - 2020 IS - 47 SP - 7373 EP - 7384 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Sand, Patrick A1 - Schmidt, Bernd T1 - Pd-catalyzed oxidative sulfoalkenylation of acetanilides and traceless removal of the catalyst directing group JF - ChemistrySelect N2 - 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. KW - arenes KW - C− H activation KW - Heck reactions KW - Palladium KW - sulfones Y1 - 2021 U6 - https://doi.org/10.1002/slct.202101009 SN - 2365-6549 VL - 6 IS - 14 SP - 3563 EP - 3567 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kwesiga, George A1 - Sperlich, Eric A1 - Schmidt, Bernd T1 - Scope and applications of 2,3-oxidative aryl rearrangements for the synthesis of isoflavone natural products JF - The journal of organic chemistry N2 - 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. Y1 - 2021 U6 - https://doi.org/10.1021/acs.joc.1c01375 SN - 0022-3263 SN - 1520-6904 VL - 86 IS - 15 SP - 10699 EP - 10712 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Sperlich, Eric A1 - Kelling, Alexandra A1 - Kwesiga, George A1 - Schmidt, Bernd T1 - Intermolecular interactions in the solid-state structures of isoflavones BT - the relationship between supramolecular structure, torsion angle, and macroscopic properties JF - CrystEngComm / The Royal Society of Chemistry N2 - 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. Y1 - 2022 U6 - https://doi.org/10.1039/d2ce00169a SN - 1466-8033 VL - 24 IS - 26 SP - 4731 EP - 4739 PB - Royal Society of Chemistry CY - London ER - TY - JOUR A1 - Sand, Patrick A1 - Schmidt, Bernd T1 - Ruthenium-catalyzed sulfoalkenylation of acetanilides and dual-use of the catalyst directing group JF - European journal of organic chemistry N2 - In contrast to vinylsulfonates and vinylsulfones, vinylsulfonamides are unreactive in Pd-catalyzed oxidative Heck-coupling reactions with acetanilides. This limitation has been resolved by using a C-H-activation protocol based on Ru-Cu-Ag-catalysis. Overall, the Ru-Cu-Ag-catalyzed conditions turned out to be more reliable and showed better reproducibility than the Pd-catalyzed C-H-activation. The coupling products thus obtained are functionalized styrenyl sulfones and -sulfonamides which can be used as starting materials for the synthesis of sulfonyl pyrroles and sulfonyl pyrrolo[2,3-c]quinolines. KW - Arenes KW - C-H activation KW - Heterocycles KW - Ruthenium KW - Sulfonamides Y1 - 2021 U6 - https://doi.org/10.1002/ejoc.202101216 SN - 1434-193X SN - 1099-0690 VL - 2021 IS - 40 SP - 5497 EP - 5506 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Dahm, Torsten A1 - Stiller, Manfred A1 - Mechie, James A1 - Heimann, Sebastian A1 - Hensch, Martin A1 - Woith, Heiko A1 - Schmidt, Bernd A1 - Gabriel, Gerald A1 - Weber, Michael T1 - Seismological and geophysical signatures of the deep crustal magma systems of the cenozoic volcanic fields Beneath the Eifel, Germany JF - Geochemistry, geophysics, geosystems N2 - The Quaternary volcanic fields of the Eifel (Rhineland-Palatinate, Germany) had their last eruptions less than 13,000 years ago. Recently, deep low-frequency (DLF) earthquakes were detected beneath one of the volcanic fields showing evidence of ongoing magmatic activity in the lower crust and upper mantle. In this work, seismic wide- and steep-angle experiments from 1978/1979 and 1987/1988 are compiled, partially reprocessed and interpreted, together with other data to better determine the location, size, shape, and state of magmatic reservoirs in the Eifel region near the crust-mantle boundary. We discuss seismic evidence for a low-velocity gradient layer from 30-36 km depth, which has developed over a large region under all Quaternary volcanic fields of the Rhenish Massif and can be explained by the presence of partial melts. We show that the DLF earthquakes connect the postulated upper mantle reservoir with the upper crust at a depth of about 8 km, directly below one of the youngest phonolitic volcanic centers in the Eifel, where CO(2)originating from the mantle is massively outgassing. A bright spot in the West Eifel between 6 and 10 km depth represents a Tertiary magma reservoir and is seen as a model for a differentiated reservoir beneath the young phonolitic center today. We find that the distribution of volcanic fields is controlled by the Variscan lithospheric structures and terrane boundaries as a whole, which is reflected by an offset of the Moho depth, a wedge-shaped transparent zone in the lower crust and the system of thrusts over about 120 km length. KW - magma reservoirs KW - distributed volcanic fields KW - reflection seismic KW - crustal magma chamber KW - deep low-frequency earthquakes KW - low velocity zone Y1 - 2020 U6 - https://doi.org/10.1029/2020GC009062 SN - 1525-2027 VL - 21 IS - 9 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Schmidt, Bernd A1 - Audörsch, Stephan T1 - Stereoselective Total Syntheses of Polyacetylene Plant Metabolites via Ester-Tethered Ring Closing Metathesis JF - The journal of organic chemistry N2 - 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. Y1 - 2017 U6 - https://doi.org/10.1021/acs.joc.6b02987 SN - 0022-3263 VL - 82 IS - 3 SP - 1743 EP - 1760 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Schmidt, Bernd A1 - Riemer, Martin T1 - Microwave-Promoted Pd-Catalyzed Synthesis of Dibenzofurans from Ortho-Arylphenols JF - Journal of Heterocyclic Chemistry N2 - 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. Y1 - 2017 U6 - https://doi.org/10.1002/jhet.2704 SN - 0022-152X SN - 1943-5193 VL - 54 IS - 2 SP - 1287 EP - 1297 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Hermanns, Jolanda A1 - Schmidt, Bernd T1 - Zur Verwendung von QR-Codes in Uni-Seminaren – ein Baustein in den neu konzipierten Übungen zur Vorlesung „Organische Chemie für Studierende im Nebenfach“ T1 - The use of QR-Codes in university courses - a building block of the newly constructed accompanying exercises for the lecture "organic chemistry" for chemistry minors JF - Chemkon N2 - Die Verwendung von QR-Codes in Begleitseminaren zur Vorlesung „Organische Chemie“ für Studierende mit Chemie im Nebenfach wird vorgestellt. Die Hausaufgaben zu den Seminaren wurden mit einem QR-Code versehen. Dieser führt zu weiterführenden Hilfen. Der Einsatz der QR-Codes sowie die Neukonzeption der Seminare wurden evaluiert. N2 - The use of QR-Codes in university courses for the lecture "Organic Chemistry" for minor students is presented. The homework to the seminars includes a QR-Code. This code leads to supporting learning aids. The use of the QR-Codes as the new concept into seminars is evaluated. KW - graded learning aids KW - homework KW - Chemical exercises KW - QR-Code Y1 - 2017 U6 - https://doi.org/10.1002/ckon.201710300 SN - 0944-5846 SN - 1521-3730 VL - 24 SP - 139 EP - 141 PB - Wiley-VCH CY - Weinheim ER -