PYRIDAZINONE DERIVATIVE

摘要

A pyridazinone derivative represented by general formula (I) and an antithrombocytic agent containing the same, wherein R represents hydrogen or C1-C4 alkyl; X represents hydrogen, chlorine or bromine; An represents pyridyl or phenyl substituted by OR<1> (R<1> representing hydrogen or C1-C4 alkyl) and A (representing hydrogen, halogen, C1-C4 alkyl or OR<2> (R<2> representing hydrogen or C1-C4 alkyl)); Y represents C1-C8 alkylene wherein one carbon atom on the straight chain is substituted by one OR<1> group (R<1> being as defined as above); and Z<1> and Z<2> represent each independently hydrogen, halogen, C1-C4 alkyl or OR<1> (R<1> being as defined above). This compound has a potent antithrombocytic activity and an excellent safety and is used as the active ingredient of a preventive or remedy for various thrombotic diseases.