| abstract |
A 1 alpha -hydroxy vitamin D3 derivative of the formula: <IMAGE> 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 compound represented by the formula above has the 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. |