Studies on fungal products. Part 8. Isolation and structure of emestrin, a novel antifungal macrocyclic epidithiodioxopiperazine from Emericella striata. X-Ray molecular structure of emestrin

Together with ergosterol, sterigmatocystin, and emericellin, a new compound designated emestrin (1), C27H22H2O10S2, was isolated from the mycelial extract of Emericella striata. Violaceic acid (6) was also isolated from the culture filtrate. The structure of emestrin (1), including the absolute configuration, was determined on the basis of a spectroscopic investigation of some derivatives and X-ray crystallography of emestrin methanol solvate. Emestrin is a new macrocyclic epidithiodioxopiperazine, derived from two molecules of phenylalanine and one molecule of benzoic acid, and has strong antifungal activity.