MICROBIAL TRANSFORMATIONS OF 6-ALPHA-EUDESMANOLIDES AND 6-BETA-EUDESMANOLIDES BY RHIZOPUS-NIGRICANS CULTURES

Microbial transformations of 6 alpha-eudesmanolides and 6 beta-eudesma nolides were accomplished using the hydroxylating fungus Rhizopus nigr icans. The eudesmane skeleton was functionalized principally at positi ons C-1, C-4 and C-8. Hydroxylation yields depended on the configurati on of the hydroxyl group at C-3, the methyl group at C-4, and the lact one ring in the substrates. Several metabolites with hydroxylation at C-9 and C-11 were also obtained with 6 alpha-eudesmanolide substrates. An inversion of configuration at C-3 may occur when the substrates ha ve an axial hydroxyl group at this carbon. Hydroxylation at C-4 was ob served only when the substrate had a 4 beta-methyl group.