A Novel and Efficient Lewis Acid Catalysed Preparation of Pyrimidines: Microwave-Promoted Reaction of Urea and β-Formyl Enamides - Barthakur, Madan G; Borthakur, Moyurima; Devi, Prarthana; Saikia, Chandan J; Saikia, Anil; Bora, Utpal; Chetia, Apurba; Boruah, Romesh C (Synlett, 2007)