| abstract |
The present invention is directed to novel thieno[2,3-d]pyrimidin-4(3H)-one, isoxazolo[5,4-d]pyrimidin-4(5H)-one and isothiazolo[5,4-d]pyrimidin-4(5H)-one derivatives and pharmaceutically acceptable salts thereof of structural formula (I), wherein the variables R1, R2, R3, X and Z are as described herein. Also provided are pharmaceutical compositions comprising the compounds of formula I as well as methods of treatment employing compounds of formula I to treat a disease or disorder characterized by abnormal bone or mineral homeostasis such as hypoparathyroidism, osteoporosis, osteopenia, periodontal disease, Paget's disease, bone fracture, osteoarthritis, rheumatoid arthritis, and humoral hypercalcemia of malignancy. |