Calcium receptor antagonists

1 2 1-6 3-7 3 1-6 4 1-6 5 6 1-6 7 12 3 1-6 4 5 A compound of the formula [I] wherein Ris optionally substituted aryl group or optionally substituted heteroaryl group; Ris optionally substituted Calkyl group, Ccycloalkyl group and the like; Ris hydrogen atom, Calkyl group, hydroxyl group and the like; Ris hydrogen atom, Calkyl group and the like; Rand Rare each Calkyl group and the like; Ris optionally substituted aryl group or optionally substituted heteroaryl group; X, Xand Xare each Calkylene group and the like; and Xand Xare each a single bond, methylene group and the like, a salt thereof, a solvate thereof or a prodrug thereof, and a pharmaceutical composition containing the compound, particularly a calcium receptor antagonist and a therapeutic agent for osteoporosis, are provided. The compound of the present invention is useful as a therapeutic drug of diseases accompanied by abnormal calcium homeostasis, or osteoporosis, hypoparathyreosis, osteosarcoma, periodontal disease, bone fracture, steoarthrosis, chronic rheumatoid arthritis, Paget's disease, humoral hypercalcemia, autosomal dominant hypocalcemia and the like. In addition, an intermediate for the compound is provided.