Influence of 1-double bond and 11β-hydroxy group on stereospecific microbial reductions of 4-en-3-oxo-steroids

The yeast Rhodotorula glutinis and the anaerobic bacterium Clostridium paraputrificum were used for stereospecific reductions of 4-chloro-11β-hydroxy-17α -methyl-testosterone and the corresponding 1-dehydro compound to prepare 5α- and 5β-H derivatives, respectively. C. paraputrificum was able to 5β-reduce both substances, whereas the 5α-reduction by R. glutinis was inhibited by the structure elements 1-en and 11β-OH so that the substrate with both structure elements was not 5α-reduced. The microbial conversion of the four steroids with and without 1-en and 11β-OH was compared in semiquantitative experiments. A number of new substances are described, 11β-hydroxy and 11-oxo derivatives of 5α- and 5β-dihydro-4-chloro-17g-methyltestosterone including some 3-OH compounds and characterized by NMR, mass spectrometric and further data.