A Facile One-pot Synthesis of Pyrido[2,3-d]-pyrimidines and Pyrido[2,3-d:6,5-d‘]dipyrimidines

Abstract

The reactions of enaminones (6-aminouracils) 1a–c and 4 with cyano olefins 2a–b and 5a–f led to the formation of pyrido[2,3- d]pyrimidines. 3a–f and 6a–f in good yield, while the treatment of 4-amino-2-thiouracil 4 with aromatic aldehydes afforded pyridodipyrimidines 7a–c.