Abstract: | The microbiological transformation by Gibberelia fujikuroi of ent-beyer-15-ene into the beyergibberellins A9 and A13, 7β-hydroxy- and 7β,18-dihydroxybeyerenolides, and of ent-beyer-15-en-19-ol into beyergibberellins A4, A7, A9, A13 and A25,and 7β-hydroxy-and 7β,18-dihydroxybeyerenolides is described. In contrast, ent-beyer-15-en-18-ol gave ent-7α, 18,19-trihydroxybeyer-15-ene, 7β,18-dihydroxybeyerenolide and ent-7α,18-dihydroxybeyer-15-en-19-oic acid again revealing the inhibitory effect of an 18-hydroxyl group on oxidative transformations at C-6β by Gibberella fujikuroi. |