Kazumi Nishijima

Synthesis and diuretic activity of 4,5-dihydro-6H-imidazo[4,5,1-ij]quinoline-6-one6-oxime-O-sulfonic acid derivatives

Abstract Using our previously reported 7-chloro-2,3-dihydro-1-(2-methylbenzoyl)-4(1H)-quinolinone 4-oxime-O-sulfonic acid potassium salt 1a (M17055) as a lead, a series of tricyclic (2a-o, 3, 4, 5) and tetracyclic (6) quinolinone oxime O-sulfonic acid derivatives were synthesized by ring annulation of the 1-(2-methylbenzoyl) moiety to the quinolinone skeleton. They were compared with furosemide and compound 1a for diuretic activity in dogs; some tricyclic 4,5-dihydro-6H-imidazo[4,5,1-ij]quinoline-6-one 6-oxime-O-sulfonic acid derivatives showed diuretic activity comparable (2c,e) or superior (2m) to the lead compound 1a. These results are discussed on the basis of a comparison of the conformational and electronic characteristics of the relevant compounds with the aid of computer graphics.

A novel quinolinone diuretic, M12285, and its activation mechanism through sulfate conjugation.

The diuretic activity of a quinolinone oxime diuretic, M12285, was examined after renal arterial, i.v. and portal injection in rats. M12285 injected into the renal artery at a dose of 1 mg/kg caused no diuretic effect, whereas i.v. and portal injections induced marked diuresis dose dependently. The minimum effective dose with portal injection was lower (1 mg/kg) than that with i.v. injection (3 mg/kg) and the start of the effect was faster with portal injection. These results indicated that some metabolic modification in the liver is necessary for the diuretic activity to appear. Accordingly, we performed in situ rat liver perfusion with M12285 and obtained several metabolites. Renal arterial injection of each fractionated metabolite of M12285 revealed that all the diuretic activity derived from one of these metabolites. From IR and 1H-nuclear magnetic resonance (1HNMR) measurements, the chemical structure of this active metabolite was assumed to be a sulfate-conjugated form of M12285 at the oxime moiety. Based on this tentative chemical structure, we synthesized the oxime sulfate of M12285 (potassium salt, M17000) and confirmed the identity of IR and 1HNMR spectra. Administration of M17000 into the renal artery induced apparent diuresis in a dose-dependent manner in both rats and dogs. These results indicate that the oxime sulfate of M12285 is responsible for the diuretic activity of M12285. Therefore, we synthesized several derivatives of M17000 and confirmed their possible therapeutic value as a novel family of diuretics, namely quinolinone oxime sulfonic acids.

Synthesis and diuretic activity of 2,3-dihydro-4(1H)-quinolinone 4-oxime-O-sulfonic acid derivatives

Abstract The diuretic activity of 6-chloro-2,3-dihydro-1-propionyl-4(1H)-quinolinone 4-oxime 1 (M12285) was previously shown to derive from a 6-chloro-2,3-dihydro-1-propionyl-4(1H)-quinolinone 4-oxime-O-sulfonic acid salt as a rat metabolite. Thus, in the present study, the potassium salt 2 (M17000) was synthesized to unambiguously establish the structure as well as the stereochemistry of the oxime. The structural features of compounds 1 and 2 were compared with those of conventional diuretics by electrostatic potential maps. Using compound 2 as a lead compound, various quinolinone oxime sulfonic acid derivatives were synthesized and the diuretic activity for elucidation of the structure-activity relationships examined. Among the compounds synthesized, 7-chloro-2,3-dihydro-1-(2-methylbenzoyl)-4(1H)-quinolinone 4-oxime-O-sulfonic acid potassium salt 3 (M17055) showed a particularly high activity.

Synthesis and diuretic activity of bicyclic fused heterocycles containing oxime-O-sulfonic acid moiety

In order to investigate the origin of the loop-type diuretic activity of M17055 (1), several variants (3-9) were designed and synthesized by modifying the quinolinone skeleton, and their diuretic activities were compared with the lead 1 and furosemide in dogs. It was found that the negative charge distribution pattern afforded by the dispositional arrangement of the 4-oxime-O-sulfonic acid and 1-N-acyl carbonyl moiety attached to the tetrahydropyridine ring system is inevitable for the development of the activity, which strongly supports the previously proposed model for the active site of the Na(+)-K(+)-2Cl(-) cotransporter. Also reported is the first synthesis of the dihydrothieno[3,2-b]pyridine-7(4H)-one ring system required in the synthesis of compound 9.