Androstanes electrolysis

The CH bonds of steroids surprisingly can be oxidized even in methanol as a solvent. The electrolysis of androstane in 0.1 M NaCl04 methanol/dichloromethane at a glassy carbon anode produces after 53% conversion 14% 6-methoxyandrostane and 27% 6-(methoxymethoxy) androstane [18, 19]. This remarkable regioselectivity is possibly... 

Kabasakalian and coworkers 87) have achieved the cathodic reduction of steroidal ketones in ethanol-20% H20 with 0.2 M (C4H9)4NC1 as the supporting electrolyte. The reactions proceeded with very high chemical yield and were rather stereoselective. Electrolysis of androstane-17 3-ol-3-one (64) at —2.6 V(SCE) gave the 3p-equatorial alcohol 65 quantitatively. Under identical conditions the exocyclie carbonyl of 66 was also reduced and the corresponding alcohol was obtained in 92% yield. But, the reaction was less stereoselective and the ratio of the 2O0-/2Oa epimers was 74/26. 

The electrolysis of ketosteroids in dichloromethane/methanol does not lead to the oxidation of unactivated CH bonds. With the 3-ketosteroids 5a-androstanone and 5a-cholestan-3-one as substrates besides the acid-catalyzed ketalization of the keto group only chlorination a to the carbonyl group occurs. The anodic oxidation of the 17-keto-steroids 5a-androstan-17-one, 3j -acetoxy-5a-androstan-17-one and 5a-androstan-3,17-dione (21) leads to the opening of the D-ring with the formation of 13,17-secosteroids, which form lactones under the weakly acidic conditions of the electrolysis and work-up (equation... 

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