Fungal metabolites. Part VI. The structure of verrucarin A: X-ray analysis of verrucarin A p-iodobenzenesulphonate

Abstract

By crystal-structure analysis of verrucarin A p-iodobenzenesulphonate, the constitution and absolute stereo-chemistry of verrucarin A, an antibiotic metabolite of Myrothecium verrucaria, have been established. The derivative crystallises as an acetone solvate with four units of C₃₃H₃₇IO₁₁S, C₃H₆O in an orthorhombic cell, space group P2₁2₁2₁, whose dimensions are a= 17·98, b= 19·66, c= 10·65 Å. Phase determination was based initially on the iodine and sulphur atoms, and Fourier and least-squares methods were used for the determination of the atomic parameters. The final value of the discrepancy R over 2126 independent reflexions is 12·5%.