| abstract |
6-(Substituted phenyl)-4,5-dihydro-3(2H)-pyridazinone compounds possessing strong platelet aggregation inhibiting activity and blood pressure depressing activity, having the general formula: ##STR1## wherein R 1 is hydrogen or lower alkyl; R 2 is hydrogen, lower alkyl, lower alkylthio or the grouping R 5 --NH-- where R 5 is lower alkyl; R 3 is phenyl, pyridyl, benzyl, lower alkyl or a substituted phenyl group carrying at any desired position on the benzene ring thereof the grouping: ##STR2## where R 1 has the same meaning as given above; R 4 is hydrogen or halogen; n is 0 or 1; and when both R 2 and R 3 are lower alkyl groups, R 2 and R 3 may be combined together with the bridging member ##STR3## between them to form the structure: ##STR4## where m is 2 or 3, as well as physiologically acceptable acid-addition salts thereof, and processes for preparing them. |