Process for preparing budesonide

摘要

A process is described for preparing budesonide which comprises the steps of: a) preparing an aqueous hydrochloric acid solution; b) reacting 16±-hydroxyprednisolone and butyraldehyde within the solution prepared in step a), in an inert atmosphere; c) quenching the reaction of step b) with water. The process of the invention enables the ratio between the A and B epimers of budesonide to be controlled.