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Compounds based on the pyrroloquinoxaline system can interact with serotonin 5‐HT3, cannabinoid CB1, and μ‐opioid receptors. Herein, a chiral pool synthesis of diastereomerically and enantiomerically pure bromolactam (S,R,R,R)‐14A is presented. Introduction of the cyclohexenyl ring at the N‐atom of (S)‐proline derivatives 8 or methyl (S)‐pyroglutamate (12) led to the N‐cyclohexenyl substituted pyrrolidine...
A simple, precise, accurate, robust chiral high‐performance liquid chromatographic (chiral HPLC) method was developed for estimation of (S)‐piperidin‐3‐amine (S‐isomer) in (R)‐piperidin‐3‐amine dihydrochloride (R‐AMP). As AMP is a high‐melting solid and nonchromophoric compound, development of a suitable chiral method is a challenging task. The proposed chiral HPLC‐UV method involves a precolumn derivatization...
The enantioselective bioactivity against pathogens (Cercospora arachidicola, Fulvia fulva, and Phytophthora infestans) and acute toxicity to Daphnia magna of the fungicide myclobutanil enantiomers were studied. The (+)‐enantiomer in an antimicrobial activity test was about 1.79–1.96 times more active than the (–)‐enantiomer. In the toxicity assay, the calculated 24‐h LC50 values of the (–)‐form, rac‐form...
Two series of indolyldiketopiperazines were synthesized starting from methyl 1‐substituted‐1,2,3,4‐tetrahydro‐β‐carboline‐3‐carboxylate hydrochlorides via N‐bromo‐succinimide (NBS) as an important reagent. All eight compounds were characterized by nuclear magnetic resonance (NMR) and elemental analysis. Furthermore, the mechanisms of NBS‐reacted rearrangements are also discussed. Chirality 26:790–792, 2014...
Two pairs of new neolignan enantiomers, (±)‐torreyayunan A (1a/1b) and (±)‐torreyayunan B (2a/2b), featuring a rare C‐8 − C‐9′ linked skeleton, were isolated from leaves and twigs of Torreya yunnanensis. Their absolute configuration involving two chiral centers was determined by combined spectral and Density Functional Theory (DFT) calculation. This is the first report of the absolute configuration...
The lipase‐catalyzed enantioselectivehydrolysis of acetates containing tetrazole moiety was studied. Among all tested lipases, Novozyme SP 435 allowed to obtain optically active 4‐(5‐aryl‐2H‐tetrazol‐2yl)butan‐2‐ol and 1‐(5‐aryl‐2H‐tetrazol‐2yl)‐propan‐2‐ol and their acetates with the highest optical purities (ee = 95%‐99%) and excellent enantioselectivity (E>100). Some of the synthesized tetrazole...
Chemical warfare nerve agents (CWNAs) are extremely toxic organophosphorus compounds that contain a chiral phosphorus center. Undirected synthesis of G‐type CWNAs produces stereoisomers of tabun, sarin, soman, and cyclosarin (GA, GB, GD, and GF, respectively). Analytical‐scale methods were developed using a supercritical fluid chromatography (SFC) system in tandem with a mass spectrometer for the...
Recalcitrant crystallization and syrup formation are frequent features of natural sugars. This is the case of d‐ribose, yielding low‐quality crystals of mixed α‐ and β‐pyranose anomers. However, large crystals of dl‐ribose can be grown easily. The crystal structures of stable d‐ribose forms I and II as well as dl‐form II have been analyzed in terms of their compatibility with the molecular aggregation...
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