Biosynthesis and synthesis of 3-benzyl-6-ethyl-3,6-bis(methylthio)-piperazine-2,5-dione, an ‘unnatural’ metabolite of Gliocladium deliquescens

Abstract

cyclo-(L-2-Aminobutanoyl-L-phenylalanyl)(1; R = Et), an unnatural analogue of the gliotoxin (2; R = CH₂OH) precursor, cyclo-(L-Phe-L-Ser)(1; R = CH₂OH), is transformed in Gliocladium deliquescens into the titled compound (4; R = Et) showing that biosynthetic introduction of sulphur may proceed without prior N-methylation or oxidative cyclisation of the phenyl group.