730 Perspecfhes in Microbiology 



hydroxy-21-acetoxy-5-pregnene-20-one (XXVIII) can be 

 oxidized by Corynebacterium to a ketone, desoxycorti- 

 costerone (XIV), as shown in the equation. 



CHjOAc CHjOH 



I I 



c=o c=o 



Corynebacterium ^ 



XXVIII XIV 



3 ^-Hydroxy-21-acetoxy- Desoxycorticosterone 



5-pregnene-20-one 



This work has been repeated and extended to other sub- 

 strates and other microorganisms by several different in- 

 vestigators, including Ercoli, Arnaudi, Molina, Turfitt, 

 Welsch and Huesghem, Zimmerman, Hughes and Schmitt 

 (36), and by Perlman et al. (24). 



REDUCTION REACTIONS 



Ring Double Bonds. While the bio-oxygenation of com- 

 pounds XI and XIII by Rhizopus produces excellent yields 

 of XII and XV, a reduction of the AMouble bond occurs 

 concomitantly to a minor degree. Thus, from progesterone 

 (XI) the 5a-stereoisomer (XXVIII) is formed, whereas 

 from Reichstein's compound S (XIII) the 5p-isomer 



(XXIX) is obtained (27, 30). Perlman, Titus, and Fried 

 (25) have shown that a 5P-stereoisomeric derivative 



(XXX) is formed concomitantly with 1 6a-hydroxylation 

 by fermentation of progesterone (XI) with an actino- 

 mycete. 



The A^^-double bond of 1 6-dehydroprogesterone (XXXI) 

 is specifically reduced in major quantities by Rhizopus 

 without altering the AMouble bond, and the configura- 

 tion of the side chain in the resulting compound (XXXII) 

 is the opposite from that occurring naturally (18). An 11a- 

 hydroxyl group is also introduced as the result of this fer- 

 mentation. Reduction of the AMouble bond by yeast was 

 accomplished as early as 1937 (14). 



