A new synthesis of 3-oxo-28-hydroxylup-20(29)-ene from the available natural triterpenoid betulin was developed. α,ω-Diketodiesters were prepared for the first time by different methods from 3-oxo-28-hydroxylup-20(29)-ene and a series of natural dicarboxylic acids. Steglich reaction conditions gave the highest yields. One of the synthesized α,ω-diketodiesters was moderately active in vitro against A-549 lung carcinoma.
Five new iridoid glycosides were isolated by chromatographic separation of extracts from the roots of three Gentiana species (Gentianaceae) growing in Eastern Siberia. Their structures were elucidated by spectral methods as 2′-O-(2′′-hydroxy-3′′ -O-β-D-glucopyranosyloxybenzoyl)swertiamarin (gentiridoid A), 2′-O-(2′′-hydroxy-3′′-O-β-D-glucopyranosyloxybenzoyl)gentiopicroside (gentiridoid B), and 3′,6′-di-Oacetyl-4′-O-(2′′,3′′-dihydroxybenzoyl)swertiamarin (gentiridoid C) from G. decumbens L. f.; ...
Pd-catalyzed arylation of grosshemin by iodoarenes synthesized products with an exocyclic C-11,13 double bond in the (E)- and (Z)-configurations. The structures of four compounds were established by X-ray crystal structure analyses. The antibacterial activity and cytotoxicity of the new compounds were assessed.
A new alkaloid named methyl 2-(3,4-dihydro-2H-pyrrol-5-yl)acetate (1), together with 24 known compounds, was isolated from the acetone extract of the fruiting bodies of Ramaria stricta. Their structures were elucidated on HR-ESI-MS and extensive 1D and 2D NMR spectroscopy. The nematocidal assay showed that three compounds, benzoic acid, 3-hydroxy-2-methylbenzaldehyde, and 4-(hydroxy)benzylbenzoic acid, exhibited a certain activity against Panagrellus redivivus.
Oxidative halogenation of lappaconitine and N-deacetyllappaconitine HBr or HCl in the presence of H2O2 in MeOH was associated upon bromination by N-20-deethylation and produced the 3′,5′-dibromo derivative of N-20-nordeacetyllappaconitine; upon chlorination, a mixture of 5′-mono- and 3′,5′-dichloro derivatives of N-deacetyllappaconitine with the monochloro-derivative dominating.