Nitrogen and selenium containing heterocycles: Part-2: Synthesis and antimicrobial activities of novel S-5-(2-oxo-2H-selenopyrano [2,3-b]quinolin-3-yl)-1,3,4-oxadiazol-2-yl-2-cyanoethanethioates

Abstract

Abstract Synthesis and antimicrobial activities of novel S-5-(2-oxo-2H-selenopyrano [2,3-b]quinolin-3-yl)-1,3,4-oxadiazol-2-yl-2-cyanoethanethioates derivatives was undertaken employing a convenient and easily accessible procedure. A Series of S-5-(2-oxo-2H-selenopyrano[2,3-b]quinolin-3-yl)-1,3,4-oxadiazol-2-yl 2-cyanoethanethioates are synthesized by a simple and efficient one-pot reaction of substituted 3-(5-mercapto-1,3,4-oxadiazol-2-yl)-2H-selenopyrano[2,3-b]quinolin-2-ones with 2-cyanoacetyl chloride and potassium carbonate in the presence dimethyl formamide as a solvent. This reaction sequence involves a nucleophilic substitution of -S-H of 1,2,3-oxadiazole with 2-cyanoacetyl chloride. The structures of all the synthesized products were confirmed with their elemental analysis, IR,1H NMR and mass spectral analysis. All the newly synthesized compounds (2a-f) were screened for in vitro antimicrobial activities (Minimum Inhibitory Concentration (MIC) of three (Staphylococcus aureus, Micrococcus roseus) and (Escherichia coli) by disk diffusion method using ampicillin as positive and Dimethylformamide (DMF) as negative control. The tested, compounds 2d and 2e were highly active against S. aureus-ATCC 25953 and M. roseus-NCTC 07523 (gram positive) and moderately active against E. coli-ATCC 25922 (gram negative), compound 2c was slightly active against M. roseus and E. coli. Compound 2e was slightly active against S. aureus and M. roseus and compounds 2a and 2b were slightly active against M. roseus.