Investigation of the importance of the C-2 and C-13 oxygen functions in the transformation of stemodin analogues by Rhizopus oryzae ATCC 11145

Incubation of 2alpha,13(R)-dihydroxystemodane (3) with Rhizopus oryzae ATCC 11145 gave 2alpha,7beta,13(R)-trihydroxystemodane (11) while biotransformation of 13(R)-hydroxystemodan-2-one (5) yielded 6alpha,13(R)-dihydroxystemodan-2-one (12) and 7beta,13(R)-dihydroxystemodan-2-one (13). Bioconversion of 2beta,13(R)-dihydroxystemodane (7) with Rhizopus afforded 2beta,7,13(R)-trihydroxystemodane (14). The results complement data from our previous work and provide more information about the effect of functional groups of stemodane substrates on the site of hydroxylation.