| abstract |
PROBLEM TO BE SOLVED: To provide a vitamin D derivative which has a high vitamin D receptor binding activity, a not so high blood calcium elevating effect and is excellent in safety, a synthetic intermediate thereof and the derivative as an active ingredient. To provide a calcium metabolism improving agent. Kind Code: A1 Formula (I): (Wherein R 1 , R 2 and R 3 each represent a hydrogen atom or a protecting group for a hydroxyl group) 20-epi-22-ethyl-23,24-dehydro-24,24-dihomovitamin D derivative represented by the following formula: . |