title: Studies on cardiotonic agents. VI. Synthesis of novel 4,5-dihydro-3(2H)-pyridazinone derivatives carrying some benzoheterocycles at the 6-position.
abstract: Several benzothiazolyl, imidazobenzothiazolyl, benzothienyl, benzothienopyrimidinyl and quinazolinyl 4,5-dihydro-3(2H)-pyridazinones were synthesized and examined for cardiotonic activity in anesthetized dogs after i.v. administration. Among them, 4-methylamino-7-(2,3,4,5-tetrahydro-5-methyl-3-oxo-6- pyridazinyl)quinazoline (36) showed potent and long-lasting inotropic activity (relative potency = 2.11, milrinone = 1). The activity of 36 was more potent than indolidan (2) (relative potency = 1.53) which is one of the most potent inotropic agents to date.
authors.affiliation: Pharmaceutical Research Laboratories, Fuji Kyowa Hakko Kogyo Co., Ltd., Shizuoka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nomoto
authors.forename: H
authors.initials: H
authors.lastname: Takai
authors.forename: T
authors.initials: T
authors.lastname: Ohno
authors.forename: K
authors.initials: K
authors.lastname: Kubo
mesh_terms: D000818:Animals; D002316:Cardiotonic Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D004285:Dogs; D007093:Imidazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects; D011724:Pyridazines / Q000138:chemical synthesis* / Q000494:pharmacology; D011799:Quinazolines / Q000138:chemical synthesis / Q000494:pharmacology; D013844:Thiazoles / Q000138:chemical synthesis* / Q000494:pharmacology; D013876:Thiophenes / Q000138:chemical synthesis / Q000494:pharmacology
chemical_list: D002316:Cardiotonic Agents; D007093:Imidazoles; D011724:Pyridazines; D011799:Quinazolines; D013844:Thiazoles; D013876:Thiophenes