Biosynthesis of bisdethiobis(methylthio)gliotoxin, a new metabolite of Gliocladium deliquescens

Abstract

Bisdethiobis(methylthio)gliotoxin (2) has been identified as an amorphous, minor metabolite of Gliocladium deliquescens and characterised via the crystalline bis-4-bromobenzoate of the corresponding didehydro-derivative. The new metabolite has been synthesised from gliotoxin (1) by reduction and methylation. Feeding experiments with [¹⁴C]-(1) and -(2), prepared biosynthetically from L-[U-¹⁴C]phenylalanine, have shown that bisdethiobis(methylthio)gliotoxin is formed (8.6% incorporation), apparently irreversibly, from gliotoxin in G. deliquescens.