water extract of onion catalyzed knoevenagel condensation reaction: an efficient green procedure for synthesis of α-cyanoacrylonitriles and α-cyanoacrylates

A useful method for knoevenagel condensation has been developed from the reaction between active methylene compound 1 and aldehyde 2 using the water extract of onion as a green catalyst. this method is suitable for variety of aldehydes including, substituted aromatic, aliphatic, α, β-unsaturated, and heterocyclic with malononitrile or ethyl cyanoacetate, and affords the α-cyanoacrylonitriles and α-cyanoacrylates in excellent yields (up to 98%). the products are isolated without column chromatography. the use of water extract of onion has several advantages such as low price, easy handling, simple work up procedure and environmentally benign.