Evaluation of the Antimicrobial Activity of Some 4H-Pyrano[3,2-h]- quinoline,7H-Pyrimido[4',5':6,5]pyrano[3,2-h]quinoline Derivatives

Several 4H-pyrano[3,2-h]quinolone (3, 5, 7, 8, 10, 11, 14, 15, 16 and 17) and 7H-pyrimido[4',5':- 6,5]pyrano[3,2-h]quinoline derivatives (9, 12, 13, 18) were prepared. These compounds were tested in vitro for their antimicrobial activity to show congruent results against the most tested microorganisms as compared with the standards Ampicillin, Streptomycin, Mycostatine and Clotrimazole. The structure activity relationship (SAR) studies of 3 and its analog compounds revealed higher potent antimicrobial activity against the most tested microorganisms. These data indicated that the activity of compounds was considerably attributed to the presence of the electrondonating groups in combination with the electron-withdrawing groups in 4H-pyrano[3,2-h]quinoline moiety. Incorporating a pyrimidine nucleus with pyranoquinoline moiety resulted in changing the potency for some compound. The structures of these compounds were established on the basis of spectral data.