Structure and synthesis of phomamide, a new piperazine-2,5-dione related to the sirodesmins, isolated from the culture medium of Phoma lingam Tode

Abstract

Several active substances are produced by the fungus Phoma lingam Tode, among which are the previously reported sirodesmins PL (1) and (2), sulphur-containing piperazinediones. A new metabolite, phomamide, also a piperazine-2,5-dione, has now been isolated from the culture filtrate of the same fungus. On the basis of physicochemical and spectroscopical data, the structure (3) of cyclo-O-(γγ-dimethylallyl)-L-tyrosyl-L-serine has been demonstrated for this compound and confirmed through subsequent synthesis. This metabolite is assumed to be an intermediate in the biosynthesis of the sirodesmin group of antibiotics.