MANUFACTURE OF VITAMIN D2, VITAMIN D3 AND DERIVATIVES THEREOF VIA REDUCTIVE ELIMINATION ERACTION OF 7,8-DIHYDROXYVITAMIN DERIVATIVES

摘要

PURPOSE:To practically obtain vitamin Ds through simplified processes in high yield by reductive elimination reaction of 7,8-dihydroxyvitamin D2 through a cyclic orthoester in the 7,8-dihydroxy groups. CONSTITUTION:A compound of formula I (R is H, dotted line is C-C bond, R is methyl, dotted line represents additional bond (for example double bond; R1-R3 are H, hydroxyl protecting group; X, Y are H, hydroxyl and its derivative) is subjected to reductive elimination reaction passing through 7,8-dihydroxy cyclic orthoester or its homologue and thionocarbonate, or elimination reaction of the 7,8-dihydroxy derivative with a metal such as reduced titanium to produce vitamin D2 and D3 or active form of vitamim D2, D3 or their derivatives.