Process for preparation of 9 alpha -chloro-11 beta -formyloxypregna-3,20-diones

摘要

Disclosed is a process for producing a compound of the formula: <IMAGE> (1.0) by reacting a compound of the formula: <IMAGE> (2.0) with: (1) a chlorinating reagent selected from an N-chloroimide or an N-chloroamide; (2) an anhydrous strong acid selected from orthophosphoric acid, alkylsulfonic acids, fluoroalkylsulfonic acids or arylsulfonic acids; and (3) anhydrous dimethyl formamide; at a temperature within the range of about -78 DEG to about 0 DEG C., under anhydrous conditions under an inert atmosphere.