Microbiological hydroxylation of steroids. Part IX. Hydroxylation of diketones and keto-alcohols derived from 5α-androstane with the fungi Rhizopus arrhizus and Rhizopus circinnans. Steroidal 18- and 19-proton magnetic resonance signals
The hydroxylations of seven diketones and keto-alcohols derived from 5α-androstane with Rhizopus arrhizus and Rhizopus circinnans are similar to, but not identical with, those observed previously using Rhizopus nigricans. R. circinnans is useful for introducing a 4α-hydroxy-group into 5α-androstane-11,17-dione.
N.m.r. shift values are given for the influence on steroidal 18- and 19-H signals of various single substituents, and of systems containing two or more substituents whose effects are not additive.