Steroid Transformations 



131 



CH, 



c=o 



HO^ 



H 



.v>V^ XXVIII 



11a -Hydroxyallopregnane- 

 3,20-(lione 



CH3 

 C=0 



-OH 



XXX 

 16a-Hydroxypregnane-3, 20-dione 



CHoOH 



XIII 

 Reichstein's Compound S 



XXIX 



llff, 17ar,21- Trihydroxypregnane 

 3. 20-dione 



CH3 



c=o 



XXXI 



16-Dehydroprogesterone 



Rhizopus 



CH3 



c=o 



HOs 



XXXII 

 lla-Hydroxy-17a-progesterone 



Reduction of Nuclear Ketone Groups. Mamoli and 

 Vercellone (14) first showed that nuclear ketone groups 

 could be reduced by fermenting yeast and, by this method, 

 steroids such as androstenedione (XVII) could be con- 

 verted to testosterone (XXIII). This work has been ex- 

 tended by others (36). 



Reduction of Side-Chain Ketone and Aldehyde Groups. 

 Fried and co-workers (6) have shown that the 20-ketone of 



