Synthesis, in-vitro antibacterial and anticancer screening of novel nicotinonitrile-coumarin hybrids utilizing piperazine citrate

An efficient, low-cost, high yield% and eco-friendly synthetic procedure is designed for the synthesis of novel series of nicotinonitrile-coumarin hybrid molecules bearing several aryl and/or heteroaryl moieties. Our strategy includes the synthesis of a novel series of 2-hydroxybenzaldehydes, bearing nicotinonitrile moiety, followed by its Knoevenagel reaction with ethyl acetoacetate in the presence of an organo-base. The above reaction is studied in different reaction conditions. The optimized conditions are performing the reaction in ethanol at 80 degrees C in the presence of 10 mol% of piperazine citrate (1:1). The in-vitro antibacterial activities of the nicotinonitrile-coumarins were evaluated against different Gram-positive and negative bacterial strains. Moreover, the in-vitro cytotoxicity of nicotinonitrile-coumarins were estimated against different eukaryotic cell lines. Compounds 5a and 5b exhibited the most promising antibacterial agents among the novel series. The structures of novel series of the target nicotinonitrile-coumarin hybrid molecules were confirmed by considering their elemental analyses and spectral data.