Synthesis and antimicrobial activity of novel pyrazolo[3,4-b]quinoline derivatives

New pyrazolo[3,4-b]quinoline derivatives have been prepared by cyclization of the intermediate 2-chloroquinoline-3-carbonitrile 7, namely 3-amino-1H-pyrazolo[3,4-b]quinoline 8a, 3-amino-1-phenyl/(p-substituted)phenyl/-1H-pyrazolo[3,4-b]-quinoline 8b-f. Furthermore, 3-[(3-aryl-4-oxothiazolidin-2-ylidene)amino]-1H-pyrazolo[3,4-b]quinolines 11a,b; 3-[(3-aryl-4-oxothiazin-2-ylidene)amino]-1H-pyrazolo[3,4-b]quinolines 12a,b and 3-(2-aryl-4-oxothiazolidin-3-yl)-1H-pyrazolo[3,4-b]quinolines 13a,b were synthesized. The antimicrobial activity was evaluated for most of the prepared compounds.