Synthesis of New 3-[(Chromen-3-yl)-Ethylideneamino]-Phenyl]-Thiazolidin-4-ones and Their Antibacterial Activity
Synthesis of New 3-[(Chromen-3-yl)-Ethylideneamino]-Phenyl]-Thiazolidin-4-ones and Their Antibacterial Activity

Summary/Abstract: A series of novel substituted thiazolidyn-4-ones were synthesized by cyclization of various Schiff bases of chromen-3-one with thioacetic acid. 3-(1-4-Amino-phenylamino)-ethyl-4-hydroxybenzopyran-2-one 3 is synthesized in high yield by condensation reaction of 4-hydroxy-3-acetylcoumarin 2 and 1,4-benzenediamine. The catalytic condensation of product 3 with benzaldehyde and their analogues (salicylaldehyde and 3-nitrobenzaldehyde) yielded corresponding 3-[1-(4-benzylidene-amino)-phenylamino]-ethyl-4-hydroxybenzopyran-2-ones 4(a-c). The cyclization reaction of compounds 4(a-c) with thioacetic acid yielded corresponding substituted thiazolidin-4-ones 5(a-c). The structures of the synthesised compounds were established by FT-IR and NMR spectrometric data and their elemental analysis. Compounds of series 4(a-c) and 5(a-c) were screened for their antibacterial activity against S. aureus, E. coli and Klebsiella by Diffusion Disc Method. Antibacterial activity of the compounds 4(a-c) and 5(a-c) against S. aureus, E. coli and Klebsiella was examined by measuring the zones of inhibition around the disks impregnated with the corresponding solutions in N,N-DMF concentration 2 mg/mL , 4 mg/mL and 6 mg/mL. Compounds of series 4 exhibited significant antibacterial activity, whereas compounds of series 5 displayed moderate activity against these microorganisms. The impact of substitutions in antimicrobial activity was also explored.

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