Process and intermediates for the synthesis of Vitamin D.sub.3
申请人:Hoffmann-La Roche Inc.
公开号:US04360470A1
公开(公告)日:1982-11-23
The present disclosure is directed to a process for the synthesis of chenodeoxychloic acid, 25-hydroxycholesterol and 1.alpha.,25-dihydroxycholesterol from 17-keto steroids. A cholic acid side chain is stereospecifically introduced by reaction of the appropriate 17-keto steroid with ethyltriphenylphosphonium halides to produce the 17-ethylidene derivative which is allowed to react with acrylic acid esters or propiolic acid esters followed by hydrogenation.