Corticosterone-11-nitrite, photolysis

The Barton nitrite photolysis was used in the conversion of nitrite of corticosterone acetate (5) to 6 during the synthesis of aldosterone actetate. ... 

The photolysis of nitrite esters has been found to be of considerable synthetic utility, particularly in functionalizing steroid methyl groups. The most spectacular application of this reaction has been a three-step synthesis of aldosterone.<59) Irradiation of corticosterone-11-nitrite (30) followed by nitric acid treatment gave aldosterone (32) in a 15% overall yield ... 

For the synthesis14 of 11-deoxy-corticosterone acetate, a convenient starting material was the readily available alcohol 39. On photolysis under oxygen, the corresponding nitrite gave the desired nitrate 40. Standard oxidation, hydrolysis and Oppenauer oxidation gave 18-nitrate 41 which was readily reduced under mild conditions with zinc dust to give the 18-... 

Barton reaction In the Barton reaction " a methyl group in the 7 -position to an OH group is converted into an oxime group. For example, corticosterone acetate (2.45) on reaction with nitrosyl chloride (NOCl) in pyridine forms its 1 l -nitrite 2.46, which on photolysis in toluene gives aldosterone acetate oxime (2.47) in 21% yield. Treatment of 2.47 with nitrous acid (HNO2) gives aldosterone acetate (2.48) (Scheme 2.40). 

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