| abstract |
The present invention relates to a new heterocyclic compound of formula (I), wherein R1 is acyl, lower alkenyl or lower alkyl optionally substituted with aryl, a heterocyclic group, etc., R2 is hydrogen, lower alkyl, hydroxy(lower)alkyl, halo(lower)alkyl, etc., R3 is hydrogen or halogen, R4 is a heterocyclic group or aryl, each of which may be substituted with suitable substituent(s), and A is (a) or (b), (wherein R?9 and R10¿ are each hydrogen, lower alkyl or substituted lower alkyl), and pharmaceutically acceptable salts thereof which are the inhibitors of bone resorption and bone metabolism, to processes for preparation thereof, to a pharmaceutical composition comprising the same and to a method for the treatment of diseases caused by abnormal bone metabolism in human being or an animal. |