3,6-disubstituted pyradazine derivatives

Abstract

A 3,6-disubstituted pyridazine derivative having excellent platelet agglutination inhibitory effects. It is useful for a preventive medicine or a therapeutic medicine for a cerebrovascular disorder such as cerebral thrombosis and cerebral embolism, an ischemic heart disease such as myocardial infarction, and a circulation disorder such as peripheral circulation disorder. A pharmaceutical composition containing a compound of the present invention as an effective ingredient and a process for preparing the same are also disclosed. The compound has the formula (I) ##STR1## wherein A represents an alkyl group having 3 to 6 carbon atoms; a cycloalkyl group having 5 to 7 carbon atoms; a phenyl group, a thienyl group, a furyl group, a thiazolyl group, a phenoxy group, a phenylalkyl group having 7 to 9 carbon atoms, a phenylthio group, a 5-6 membered saturated heterocyclic group containing one or more nitrogen atoms, a pyridyl group or an imidazolyl group each of which may have at least one substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms and a halogen atom; B represents (a) --NH--D wherein D represents ##STR2## (4) --CH.sup.3 R.sup.4 ; or (5) an alkyl group having 3 to 8 carbon atoms; or ##STR3## and the ring C represents a benzene ring.