The structure of tautomycin, a dialkylmaleic anhydride antibiotic.

Abstract
The chemical structure of tautomycin (C41H66O13) was determined by chemical degradation, spectroscopic analysis and 2D INADEQUATE of tautomycin labeled with [1,2-13C]acetate. Tautomycin exists in methanol-buffer solution (1% diethylamine-formic acid, pH 7.3) as an equilibrium mixture of a 2,3-dialkylmaleic anhydride and its dicarboxylic acid in a ratio of approximately 5:4.