The biosynthesis of fungal metabolites. Part IV. Tajixanthone: 13C nuclear magnetic resonance spectrum and feedings with [1-13C]- and [2-13C]-acetate

Abstract

The ¹³C N.m.r. spectra of tajixanthone (I) and related compounds (VI)–(XV) have been completely assigned Spectra of tajixanthone derived by incorporation of [1-¹³C]- and [2-¹³C]-acetate show patterns of enrichment consistent with a biosynthetic pathway in which the xanthone arises by ring scission of 1,8-dihydroxy-3-methyl-9-anthrone (chrysophanol anthrone), derived on a β-ketide pathway, with introduction of C- and O-prenyl units from mevalonate.