Studies on nilvadipine. I. Synthesis and structure-activity relationships of 1,4-dihydropyridines containing novel substituents at the 2-position.
The synthesis of new 1,4-dihydropyridine derivatives containing novel substituent at the 2-position of the nucleus via the key intermediate 2-formyl-1,4-dihydropyridines (X), is described. The aldehydes (X) were prepared by hydrolysis of the acetals (IX) which were obtained from aryl aldehyde (V) and alkyl 4,4-dialkoxyacetoacetate (VI) by the Knoevenagel reaction and treatment with alkyl 3-aminocrotonate (VIII) according to the modified Hantzsch method. The formyl group of the aldehydes (X) was reactive enough to be converted to a variety of functional groups such as hydroxymethyl, cyano, substituted iminomethyl, carbamoyl, semicarbazone, substituted vinyl, ethynyl, and so on. In all of the novel compounds we prepared, 2-hydroxymethyl- and 2-cyano-1,4-dihydropyridines (IV and XXII) were found to possess potent activities in preliminary biological evaluations on hypotension in normotensive rats and on an increase in coronary blood flow in pentobarbital-anesthetized dogs. Optimization research in order to obtain a more potent compound was accomplished in the 2-hydroxymethyl- and 2-cyano-1,4-dihydropyridine series. We selected isopropyl 2-cyano-3-methoxycarbonyl-4-(3-nitrophenyl)-6-methyl-1,4-dihydropyridine -5-carboxylate (XXIIj) as a candidate compound for further biological evaluation studies. Fortunately, XXIIj (nilvadipine) has been accepted in clinical use for the treatment of hypertension.
Satoh
Y
Y
New Drug Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan.
Ichihashi
M
M
Okumura
K
K
D000818:Animals; D000959:Antihypertensive Agents / Q000138:chemical synthesis* / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000138:chemical synthesis* / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers; C035100:nilvadipine; D009543:Nifedipine