The microbiological transformation of some ent-13-epi-manoyl oxide diterpenes by Gibberelle fujikuroi

Abstract

Incubation of ent-19-hydroxy-13-epi-manoyl oxide with Gibberella fujikuroi afforded ent-12a,19-dihydroxy-13-epi-manoyl oxide and ent-7B,12a19-trihydroxy-13-epi-manoyl oxide, the first of which was transformed by chemical methods into varol (ent-12a-hydroxy-13-epi-manoyl oxide). The incubation of ent-3B-hydroxy-13-epi-manoyl oxide (ribenol) with the same fungus gave the 12B-hydroxy, the 11B-hydroxy and the 11B,12B-dihydroxy derivatives of ribenol, the first of which was identical with varodiol.