Method for introducing a 1,2 double bond into 4-azasteroids, and crystalline phroscor(R) and pharmaceutical compositions thereof.

摘要

A process for introducing a 1,2 double bond into a compound of the formula which comprises the process of (a) treating the compound of formula I with oxalyl chloride; (b) brominating the product of step (a) followed by in situ dehydrobromination; (c) deprotecting the product of step (b) to yield the alpha and beta isomers; (d) dehydrobrominating the product of step (c), which results in the introduction of a double bond at the 1,2 position.