Uncatalyzed Condensation of Active Methylene Compounds with Aldehydes or Ketones in Aqueous Medium

The Knoevenagel condensations of various carbonyl compounds with active methylene compounds were reported in water medium without adding any catalyst. The condensation of aromatic aldehydes with active methylene compounds like malononitrile, cyanoacetamide and ethyl cyanoacetate has been found to proceed very efficiently at room temperature giving excellent yields, but the condensation of heteroaromatic, alpha,beta-unsaturated and aliphatic aldehydes with active methylene compounds proceeded smoothly in 50 similar to 65 degrees C with good yields and the reactions of aromatic, aliphatic ketones as well as p-phthalaldehyde with malononitrile also proceeded in 75 similar to 85 degrees C with moderate yields. The work-up procedure is simple, efficient and environment-friendly.