The biosynthesis of antibiotic 1233A (F-244) was studied by feeding 13C-labeled precursors to the producing organism, Scopulariopsis sp. F-244. 13C NMR spectroscopy established that 1233A is derived from 4 methionines and 7 acetates. Seven acetates are condensed to form a hexaketide and 4 methyl residues from methionine are introduced into the main skeleton. The beta-lactone is derived from the...

A convenient zinc(II) chloride-catalyzed regioselective propargylation/amination/cycloisomerization process has been developed for the synthesis of substituted pyrrole derivatives from propargylic acetates, enoxysilanes and primary amines. Various aromatic and aliphatic propargylic acetates participate well in the reaction, providing the propargylation/amination/cycloisomerization products in g...

The highly selective chemosignaling behaviors for hydrazine by a reaction-based probe of dichlorofluorescein and resorufin acetates were investigated. Hydrazinolysis of latent dichlorofluorescein and resorufin acetate fluorochromes caused prominent chromogenic and fluorescent turn-on type signals. The probes selectively detected hydrazine in the presence of commonly encountered metal ions and a...

A highly regio- and stereoselective anomeric esterification of 3-O-allyl (or benzyl, or benzoyl)-4,6-O-isopropylidene-alpha,beta-d-glucopyranose with acetyl chloride, or allyl chloroformate, or ethyl chloroformate gave the corresponding 2-OH, 1-beta-acetates or -carbonates in excellent yields. The 2-OH, 1-beta-acetates were readily converted to the corresponding 2-O-acetylated glucopyranosyl tr...

Cell suspension cultures from hypocotyl-derived callus of Hyssopus officinalis were found to produce two sterols i. e. beta-sitosterol (1) and stigmasterol (2), as well as several known pentacyclic triterpenes with an oleanene and ursene skeleton. The triterpenes were identified as oleanolic acid (3), ursolic acid (4), 2alpha,3beta-dihydroxyolean-12-en-28-oic acid (5), 2alpha,3beta-dihydroxyurs...

A series of ethyl 2-[2-arylamino-4-(thiophen-2-yl)thiazol-5-yl] acetates (5a-5k) and ethyl 2-[2-(arylhydrazino)-4-(thiophen-2-yl)thiazol-5-yl] acetates (9a-9g) were synthesized and screened for their anti-inflammatory, analgesic, and antioxidant activities. In vivo test results showed that the compounds with halogen substitution (5c, 5g, 5h, 5i and 5j) at the para position on the 2-aryl amino g...