| 摘要 |
The invention relates to pyridazinone compounds of the general formula I: <CHEM> wherein R<1> represents one to four substituents, which may be the same or different and are selected from H, OH, halogen, NO2, unsubstituted or C1-C4 alkyl substituted amino, C1-C4 alkyl, C1-C4 halogen substituted alkyl, O-ALK-NR<4>R<5>, C1-C4 alkoxy, whereby two substituents taken together may also represent a methylenedioxy group ; R<2> and R<3> represent independently H or C1-C4 alkyl; R<4> and R<5> represent independently H or C1-C4 alkyl, or form together with the nitrogen a 5- or 6- membered ring; X represents S or O; the dotted line represents an optional bond; and their pharmaceutically acceptable salts. The compounds according to the invention have a cardiotonic, blood platelet aggregation inhibiting, systemic vasodilator, pulmonary vasodilator, and bronchodilator activity, and more particularly they show a very potent increase of the force of the muscular contractions of the heart, reduce afterload on the heart, improve pulmonary blood flow, and improve airways ventilation. |
