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.