NOVEL VITAMIN D3 DERIVATIVE AND ITS PREPARATION

摘要

NEW MATERIAL:A compound of formula I. EXAMPLE:24,24-Difluoro-1alpha,25-dihydroxyvitamin D3. USE:Useful medicines having a great biological activity like vitamin D. PROCESS:A provitamin D3 derivative of formula II (R1, R2 and R3 are H or OH-protecting groups) is irradiated with ultraviolet light in a low-boiling solvent, e.g. hexane, at about room temperature, in the atmosphere of an inert gas, e.g. argon, to give a previtamin D3 derivative of formula III, which is isomerized thermally to form a vitamin D3 derivative of formula IV. The OH-protecting groups are eliminated from the resulting compound if necessary, in an inert solvent, e.g. hexane, in the atmosphere of an inert gas, e.g. argon. The novel compound of formula II can be obtained from a compound of formula V (X1 and X2 are H's or single bonds C-C).