A series of novel 4, 5-dihydro-5-methyl-6-(2 or 4-substituted 7-quinazolinyl)-3(2H)-pyridazinones was synthesized and examined for cardiotonic activity in anesthetized dogs. The 4-substituted aminoquinazolines generally showed potent and long-lasting inotropic activity. Fall in the activity was observed on the introduction of substituent at the 2-position of the quinazoline ring. The 3-substituted 4 (3H)-quinazolinimines generally exhibited weak activity. Ca+2 sensitizing effect of the 4-substituted amino derivatives was also examined in chemically skinned fiber from papillary muscle of guinea pig. The alkylamino derivatives exhibited small sensitizing effect, while the benzylamino derivatives exhibited large effect. Among them, KF15232 (Ix) was found to have the most potent cardiotonic and Ca2+ sensitizing activities.
Novel pyridazinone derivatives and pharmaceutical preparations containing them
申请人:KYOWA HAKKO KOGYO CO., LTD.
公开号:EP0326307A2
公开(公告)日:1989-08-02
Novel pyridazinone compounds having cardiotonic activity are disclosed, being compounds represented by the following formula;
and their pharmaceutically acceptable acid addition salts.