Fungal products. Part 22. X-Ray and molecular structure of the mono-acetate of colletotrichin

Abstract

The structure and relative stereochemistry (1) for colletotrichin, a metabolite of Colletotrichum capsici, previously isolated under the name acetylcolletotrichin, is deduced from an X-ray crystallographic study of the mono-acetate (2). The crystals are orthorhombic P2₁2₁2₁, a= 16.370(12), b= 11.919(3), c= 15.506(9)Å, Z= 4. Using 1 554 independent ‘observed’ intensities, the refinement converged to R 0.058 (R′ 0.074). The metabolite consists of a tetra-substituted γ-pyrone, containing all non-hydroxylic oxygens, and linked to an unusual bicyclic terpene.