Synthesis of 19-acetylthio-3-β-acetoxy-9,10-secochola-1(10),5Z,7E-triene, and 1-β-acetylthio-3-β-acetoxy-9,10-secochola-5Z,7E,10(19)-triene. An approach to 1β- and 19-thiolation of the vitamin D skeleton

Abstract

Reaction of 1-α-methylsulphonyloxy or 1-α-(p-tolylsulphonyloxy) derivatives of vitamin D₃-acetate with KSAc in dimethyl sulphoxide resulted exclusively in 19-acetylthiolation; the same reaction with 1-α-p-tolylsulphonyloxy-(6R)-methoxycyclovitamin D₃ and its corresponding 25-hydroxy derivatives offered a selective route to 1-β-thiol analogues of vitamin D₃ and 25-hydroxyvitamin D₃, both of which were capable of competing with 1α,25-dihydroxyvitamin D₃ for chick intestinal cytosolic receptor.