Synthesis of active forms of vitamin D. Part IX. Synthesis of 1α,24-dihydroxycholecalciferol

Abstract

24-Oxocholesterol (1)(readily available from fucosterol) was converted by three steps into 1α,24ξ-dihydroxycholesterol (4). From the corresponding triacetate (5), 1α,24ξ-dihydroxycholecalciferol (9) was prepared via the 5,7-diene (8). The C-24 epimers of compound (4) were resolved by silica gel column chromatography of the monohydroxydibenzoates (7), and were separately transformed into the corresponding 1α,24-dihydroxycholecalciferol epimers.