Synthesis and Biological Evaluation of Some New Thiazolo[2,3-b]quinazolines and Their Derivatives

Abstract

9-Methoxy-4-phenyl-3,4,5,6-tetrahydrobenzo[h]quinzoline-2(1H)-thione (2), obtained by the condensation of (E)-2-benzylidene-7-methoxy-3,4-dihydronaphthalen-1(2H)-one (1) with thiourea, on reaction with chloroacetic acid, a-bromopropionic acid and 1,2-dibromoethane furnishes compounds, 3, 4 and 5 and not their other possible isomers, 7, 8 and 9, respectively. Arylidene thiazolidinones 6 have been obtained by two routes. Compounds 3-5 represent a novel heterocyclic system. The structural assignments of 3, 4 and 5 are based on elemental analysis, ¹H NMR, IR and mass spectral data. The condensed 4-thiazolidinones (3-5) and their 2-arylidene derivatives (6a-c) were screened for antimicrobial activity and showed promising inhibition of S. aureus, C. diphtheriae, P. aeruginosa and E. coli bacteria.