Two new C-nor/D-homo corticosteroids formed by dehydration rearrangement of a 12beta-hydroxy corticoid.

Two new C-nor/D-homo corticosteroids were isolated from the filtrate of the triene carbonate intermediate during the production of betamethasone. Their structures were elucidated based on NMR spectroscopic studies and mass spectral analyses. The mechanism of formation of each of these two steroids was postulated as a Wagner-Meerwein rearrangement of the corresponding 12beta-hydroxy steroid. The new 12beta-hydroxy corticosteroid was also isolated from the fermentation process of betamethasone synthesis. Its structure was identified via NMR and mass spectroscopic studies. Treatment of the new 12beta-hydroxy corticoid with PCl(5) at low temperature provided two C-nor/D-homo compounds in a ratio of 1:1. Conversion of 12beta-hydroxy corticoid into a corresponding 12beta-mesylate followed by heating in HOAc to 110 degrees C in the presence of NaOAc produced a mixture of the rearranged products in a 1:4 ratio.