This invention relates to novel 20,21-acetonides of pregnenes and novel 16 beta -alkyl-17 alpha ,20,21-trihydroxy pregnenes, and processes for the production thereof. The compounds of this invention are useful intermediates; they provide an improved means for obtaining valuable 9 alpha -fluoro-16 beta -alkylprednisolones and their 21-acylates which are known and highly active anti-inflammatory agents, for example, 9 alpha -fluoro-16 beta -methylprednisolone (Betamethasone).
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