Process improvements in the synthesis of corticosteroid 9, 11β-epoxides

X Fu, CH Tann, TK Thiruvengadam

Index: Fu, Xiaoyong; Tann, Chou-Hong; Thiruvengadam Organic Process Research and Development, 2001 , vol. 5, # 4 p. 376 - 382

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Citation Number: 6

Abstract

Corticosteroid 9, 11β-epoxides are key intermediates in the preparation of pharmaceutically important compounds such as betamethasone, mometasone, beclomethasone, and dexamethasone. A new process for the 9, 11β-epoxide was developed using a PCl5- mediated regioselective dehydration of 11α-hydroxysteroid to form the corresponding Δ9, 11 double bond. The olefin is then converted into 9α, 11β-bromoformate by treatment with 1, ...