PURPOSE: To provide a new compound useful for preventing or curing osteoporosis, curing dermatic ulcer, and as an antineoplastic agent.
CONSTITUTION: The compound of formula I [X is H or acyl derived from vitamin A acid; Y is acyl derived from vitamin A acid; R is a group of formula II (R1 and R2 are each H or combined into C=C double bond; R3 is H, 1-4C alkyl or OX; R4 is H or OH)], e.g. 1α-hydroxycholecalcipherol vitamin A acid (whole trans-type)ester. The compound of the formula I can be obtained by the following process: the OH group of a 1-acetoxyvitamin D compound of formula III [R' is of formula IV (R3' is H, 1-4C alkyl or O-Ac; Ac is acetyl; R4' is H or O-Ac)] is protected followed by deacetylation and then esterification with vitamin A acid followed by elimination of the protecting group for the OH group. The present compound can be made into a pharmaceutical preparation in the form of powder, tablets, capsules, granules, injection, suppository, or ointment, its dose being 0.1-100μg/adult/day.