Fluorine derivatives of vitamin D3 and process for producing the same

摘要

There are disclosed herein novel derivatives of 26,26,26,27,27,27-hexafluorovitamin D3 providing excellent pharmacological effects, and a process for the preparation thereof. These novel compounds are represented by the general formula wherein R1 and R2 each denotes a hydrogen atom or a protecting group for the hydroxyl group; R3 and R4 each denotes a hydrogen atom, a hydroxyl group or a protected hydroxyl group and R4' and R5' each denotes a hydrogen atom, or alternatively R3 and R3' together or R4 and R4' together denote an oxo group; provided that R3, R3', R4 and R4' cannot denote hydrogen atoms simultaneously. The process for the preparation comprises subjecting a previtamin D3 derivative represented by the formula wherein R1, R2, R3, R3', R4 and R4' are as defined above, to thermal isomerization to give a vitamin D3 derivative represented by the general formula wherein R1, R2, R3, R3', R4 and R4' are as defined above, and optionally subjecting it to a deprotection reaction.