blennolide-c and diversonol

The first stereoselective total synthesis of gonytolide C, which is a monomeric unit of an innate immune promoter gonytolide A, has been accomplished from the aldol reaction between acetophenone derived from orcinol and butyrolactone containing α-keto ester followed by the excellent diastereoselective intramolecular cyclization. The first total synthesis of gonytolide G has been achieved by the oxidation of benzylic methyl in gonytolide C. Additionally, total synthesis of lachnone C and a formal synthesis of blennolide C and diversonol have been achieved by this synthetic method.

Topics: 4-Butyrolactone; Chromones; Lactones; Proton Magnetic Resonance Spectroscopy; Stereoisomerism; Temperature; Time Factors; Xanthones

Chemical investigation of the fungal strain Microdiplodia sp. isolated from the shrub Lycium intricatum led to the isolation of four new compounds: a hexahydroxanthone (2), a 2,3-dihydrochroman-4-one (3), a 7-oxoxanthone derivative (4), and a 1,4-oxazepan-7-one (5). The relative configurations of the new compounds were determined by intensive NMR investigations, notably NOESY experiments at different temperatures. The absolute configurations of the well-known fungal metabolite diversonol (1) and of other xanthone derivatives (3, 4) were established by means of TDDFT ECD calculations. Most of the metabolites were biologically active, with antibacterial activity against Legionella pneumophila and/or antifungal activity against Microbotryum violaceum.

Topics: Anti-Bacterial Agents; Antifungal Agents; Ascomycota; Bacillus megaterium; Basidiomycota; Crystallography, X-Ray; Escherichia coli; Legionella pneumophila; Lycium; Microbial Sensitivity Tests; Molecular Structure; Spain; Xanthones

Topics: Anti-Bacterial Agents; Esters; Molecular Structure; Xanthones

Topics: Molecular Structure; Mycotoxins; Stereoisomerism; Xanthones