Microbial transformation of two 15α-hydroxy-ent-kaur-16-ene diterpenes by Mucor plumbeus

The microbiological transformation of candidiol (15α,18-dihydroxy-ent-kaur-16-ene) by Mucor plumbeus led to 3β,15α,18-trihydroxy-ent-kaur-16-ene, 6α,15α,18-trihydroxy-ent-kaur-16-ene, 3α,15α,18-trihydroxy-ent-kaur-16-ene, 11β,15α,18-trihydroxy-ent-kaur-16-ene and 15α,17,18-trihydroxy-11β,16β-epoxy-ent-kaurane, whilst the incubation of 15α,19-dihydroxy-ent-kaur-16-ene gave 9β,15α,19-trihydroxy-ent-kaur-16-ene, 3α,15α,19-trihydroxy-ent-kaur-16-ene, 11β,15α,19-trihydroxy-ent-kaur-16-ene, 6α,15α,19-trihydroxy-ent-kaur-16-ene, 15α,17,19-trihydroxy-11β,16β-epoxy-ent-kaurane, 19-(β-d-glucopyranosyl)-15α-hydroxy-ent-kaur-16-ene and 19-(β-d-glucopyranosyl)-15-oxo-ent-kaur-16-ene. An interesting rearrangement in dilute acid medium of 9β,15α,19-trihydroxy-ent-kaur-16-ene into 16-oxo-19-hydroxy-ent-abiet-8(9),15-diene, is also described in this work.