Novel 4-aminopyrimido[4,5-b]quinoline derivatives as potential antimicrobial agents

Two series of 4-aminopyrimido[4,5-b]quinoline derivatives substituted in the 2-position 6a-c and/or in 1-position 9a-e have been prepared by facile routes starting from 2-amino-3-cyanoquinoline 2,2-chloro-3-cyanoquinoline 4 and 2-arylamino-3-cyanoquinolines 8a-d. The reactions involved simple fusion with thiourea or urea and, in some cases, with guanidine. The prepared compounds were in vitro tested for antimicrobial activities against some selected Gram-positive, Gram-negative bacteria and fungi. The products containing the thio-function were the most active followed by those containing the imino-function while the carbonyl containing derivatives were without significant antimicrobial effect.