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.