With repeated silica gel, octadecyl silica(ODS), and Sephadex LH-20 column chromatography, normal-phase and reverse-phase high performance liquid chromatography(HPLC), etc., a pair of new enantiomers and 5 known compounds were separated from the 95% ethanol extract of Chloranthus multistachys. These compounds were identified by the nuclear magnetic resonance spectroscopy(including 1 D-NMR and 2 D-NMR), single-crystal X-ray diffraction, circular dichroism(CD) spectroscopy, mass spectrometry(MS), and some other methods as(1R,4R,5R,8S,10R)-chloraeudolide H(1 a),(1S,4S,5S,8R,10S)-chloraeudolide H(1 b), hydroxyisogermafurenolide(2), 4α-hydroxy-5α,8β(H)-eudesm-7(11)-en-8,12-olide(3), chloraniolide A(4), chlorantene D(5), 4α,8β-dihydroxy-5α(H)-eudesm-7(11)-en-8,12-olide(6). Compounds 1 a and 1 b are a pair of new eudesmane-type sesquiterpene enantiomers, and compounds 2-4 were isolated from C. multistachys for the first time.
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http://dx.doi.org/10.19540/j.cnki.cjcmm.20210429.204 | DOI Listing |
J Am Chem Soc
December 2024
School of Natural Sciences, Department Chemie, and Catalysis Research Center (CRC), Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
By coupling a photochemical and a thermal step, a single chiral catalyst can establish a photostationary state in which the enantiopure form of a chiral compound is favored over its racemate. Following this strategy, 3-substituted 4,7-diaza-1-isoindolones were successfully deracemized (74-98% yield, 86-99% ) employing 2.5 mol % of a photocatalyst.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Compared with chiral β-amino phosphorus compounds, which can be easily derived from natural optically pure α-amino acids, obtaining chiral β-amino phosphorus derivatives remains a challenge. These derivatives, which cannot be derived from chiral natural amino acids, possess unique biological activities or potential catalytic activities. Herein, highly enantioselective hydrogenation for the preparation of chiral β-amino phosphorus derivatives from -β-enamido phosphorus compounds is reported by using a green and low-cost earth-abundant metal nickel catalyst (13 examples of 99% ee).
View Article and Find Full Text PDFJ Org Chem
December 2024
Chemistry and Materials Program, College of Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Kohto-ku, Tokyo 135-8548, Japan.
Both enantiomers of 2-ethylquinazolin-4-ones bearing -CHO/CDO and CHO/CHO phenyl groups at the N3 position were prepared. These are isotopic atropisomeric compounds based on a remote and conformationally flexible H/D and C/C discrimination, and it was found that a CHCl solution of -CHO/CDO derivative shows a slight specific optical rotation. Furthermore, diastereomeric quinazolinone derivatives bearing a chiral carbon were prepared, and their stereochemical purities and rotational stability as well as the isotopic atropisomerism were verified by H NMR and chiral high-performance liquid chromatography (HPLC) analyses.
View Article and Find Full Text PDFOrg Chem Front
December 2024
Department of Chemistry, University of Basel St Johanns-Ring 19 Basel 4056 Switzerland https://www.chemie1.unibas.ch/Bmayor/.
This work explores the use of a cross-shaped organic framework that is used as a template for the investigation of multi-functionalized chromophores. We report the design and synthesis of a universal cross-shaped building block bearing two bromines and two iodines on its peripheral positions. The template can be synthesized on a gram scale in a five-step reaction comprising an oxidative homo-coupling macro-cyclization.
View Article and Find Full Text PDFForensic Sci Int
December 2024
Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Sciences, University of Graz, Schubertstraße 1, Graz A-8010, Austria. Electronic address:
Synthetic cathinones belong to one of the biggest and most popular classes of New Psychoactive Substances. Each year, new derivatives appear on the drug market, traded under various labels like "bath salts" or "legal highs". In recent years, the emergence of new cathinone derivatives, containing a cyclohexyl residue, has been observed.
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