Microwave Assisted Knoevenagel Condensation: Synthesis and Antimicrobial Activities of Some Arylidene-malononitriles

Eleven arylidene-malononitriles, viz. 2-(1-naphthyl idene)-malononitrile ( 1), 2-(4-N,N -dimethylaminobenzylidene)-malononitrile (2), 2-(4-hydroxy-3-methoxybenzylidene)-malononitrile ( 3), 2-(3-methoxybenzylidene)-malononitrile ( 4), 2-(2methylbenzylidene)-malononitrile( 5), 2-(4-hydroxybenzylidene)-malononitrile ( 6), 2-(3-methylbenzylidene)-malononitrile (7), 2-(2,4-dimethoxybenzylidene)-malononitrile ( 8), 2-(3-nitrobenzylidene)-malononitrile (9), 2-(9-anthracenylidene)-malononitrile (10 ) and 2-[3-(4-dimethylaminophenyl)-allylidene]-malononitrile ( 11 ) were prepared by Knoevenagel condensation reaction of malononitrile with corresponding ar omatic aldehydes in presence of ammonium acetate (NH 4OAc), using microwave irradiation under solvent free condition. The reaction is clean with shorter reaction time, mild reaction condition, eco-friendly, excellent yields as compar ed to conventional methods and reduces the use of v olatile organic compounds (VOCs). Variety of functional groups such as nitro, chloro, amino and ether survived under t he reaction conditions. The structures of the arylidene-malonon itriles have been established on the basis of their IR, NMR spectral data and elemental analyses. These compounds were screened for their antibacterial activities against five pathogenic organisms: Bacillus cereus (BTCC 19), Staphylococcus aureus (ATCC 6538) , Vibrio choloriae , Shigella dysenteriae (AE 14396) and Salmonella typhi (AE 14612) and antifungal activities against two or ganisms: Aspargilllus flavus and Saccharomyces cerevisiae using disc diffusion method and poisoned-food technique respectively. Some of them were found to posse ss significant activity, when compared to standard dru gs.