A novel and efficient synthesis of betamethasone has been developed from the readily available 9α-hydroxyandrost-4-ene-3,17-dione (9αOH-AD). The 16α-methyl was introduced stereoselectively with CH3Br and converted to the 16β-methyl, the 17-side chain was installed with 2-chlorovinyl ethyl ether in the place of the toxic KCN/HOAc, and a mild fermentation was employed for the 1,2-dehydrogenation, replacing
Synthesis of 16-unsaturated pregnanes from 17-keto steroids
申请人:The Upjohn Company
公开号:US04216159A1
公开(公告)日:1980-08-05
17-Keto steroids (I) in their protected form (IIa or IIb) are reacted with a metalated olefin (VI) to give a 21-aldehyde (IV) which is readily transformed to a 16-unsaturated pregnane (V) which is useful in the production of commercially important substituted corticoids.