Vitamin D derivatives, process for producing the same and their use in the differentiation of tumor cells

摘要

Vitamin D derivatives of the formula <IMAGE> where R1, R2 and R3 which may be the same or different each represents a hydrogen atom or a hydroxyl group; X is an oxygen atom, the group of the formula OR4 (where R4 is either a hydrogen atom or a lower alkyl having 4 to 6 carbon atoms that may or may not be substituted by a hydroxyl group), or the group of the formula=N-OR5 (where R5 is either a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms that may or may not be substituted by a hydroxyl group, an amino group or a lower alkylamino group having 1 to 3 carbon atoms), provided that the carbon atom at 20-position is linked to X by a single bond when X is the group of the formula OR4, and by a double bond in other cases, and a process for preparing the derivatives are disclosed. The derivatives have both the immunoregulating action and the ability to induce differentiation in tumor cells and hence are useful as medicines such as antiallergic agents, antirheumatic agents and antitumor agents.