NOVEL PYRIDAZINONE DERIVATIVE, ITS PRODUCTION AND ITS UTILIZATION AS DRUG

The present invention provides pyridazinone derivatives of the general formula: (I) wherein Het is a mono- or bicyclic heterocycle with one or two nitrogen atoms, B-C is a -CHR1-CH2-, -CR1=CH-, -CHR1-O-, -O-CHR1-, -CHR1-NH- or -NH-CHR1- group, R1 being a hydrogen atom or an alkyl radical, and A is an amiono, alkylcarbonylamino, aminocarbonylamino, aminothiocarbonylamino, alkylaminothiocarbonylamino, alkylamionocarbonylamino, N'-cyanoguanidino or N'-cyano-N''-alkylguanidino group, a substituted phenyl ring or heterocycle attached via a nitrogen or sulphur atom, or a mono- or bicyclic substituted heterocycle with 1 to 3 nitrogen atoms, one ring nitrogen atom being directly attached to Het; as well as the physiologically acceptable salts thereof. The present invention also provides processes for the preparation of these pyridazinone drivatives and pharmaceutical compositions containing them for the treatment of heart and circulatory diseases.