Condensed thiadiazole derivative, method of its production, and use thereof

摘要

(1) a compound represented by the following formula (I): <IMAGE> (I) wherein R represents a hydrocarbon group or heterocyclic group which may be substituted; the ring A represents a pyridine ring having a substituent or a thiazole ring which may be substituted; or a pharmaceutically acceptable salt thereof, and a method of its production, and (2) an endothelin receptor antagonist, an cathepsin B inhibitor or a bone resorption suppressor having as an active ingredient a compound represented by the following formula (I'): <IMAGE> (I') wherein R has the same definition as in term (1); the ring A' represents a pyridine ring or thiazole ring which may be substituted; or a pharmaceutically acceptable salt thereof.