VITAMIN D_ DERIVATIVES HAVING A SUBSTITUENT AT 2-POSITION

摘要

1.alpha.-hydroxy vitamin D3 derivatives of the formula: <IMG> where R1 is a hydroxyl group, an amino group or the group OR' (where R' is a lower alkyl group having 1 to 7 carbon atoms that may or may not be substituted by a hydroxyl group, a halogen atom, a cyano group, a lower alkoxy group having 1 to 3 carbon atoms, an amino group, or an acylamino group); R2 is a hydrogen atom or a hydroxyl group, and a process for preparing the same are disclosed. The compounds represented by the formula above have a calcium control action and the ability to induce differentiation in tumor cells and, therefore, are useful as an antitumor agents and a medicine for treating calcium dysbolism-caused diseases.