Urea: A Highly Efficient Recyclable Organocatalyst For Synthesis of Bioactive Annulated Pyrimidine via Knoevenagel-Michael Addition Pathway In Aqueous Ethanol

A highly efficient synthetic procedure were developed for the synthesis of bioactive pyrido [2,3-d] pyrimidines by  one-pot three component reaction of 6-amino 1,3-dimethyluracil, active methylene compounds and substituted aromatic aldehydes catalyzed using  urea catalyst  in aqueous media at room temperature. Mild reaction conditions, excellent yields, operational simplicity, no tedious separation procedures and clean reaction profiles are the key advantages of the present method. The bioactive synthesized derivatives showed no significant effect of electron donating or withdrawing moieties of the reacting aromatic aldehydes. This protocol produced the desired products in high yields (85-95 %) and short reaction times (45-75min) with reusability of reaction medium. Synthesized compounds were characterized by IR, 1HNMR & 13C NMR and mass spectral data.