Synthesis of the novel pyrimido[1,6-a]pyrimidine and imidazo[1,2-c]pyrimidine derivatives based on heterocyclic ketene aminals

A concise and efficient route for the synthesis of pyrimido[1,6-a]pyrimidines and imidazo[1,2-c]pyrimidines by simply refluxing a reaction mixture of different heterocyclic ketene aminals and N,N′-bis(arylmethylidene)arylmethane was developed. This protocol provides an alternative method for application in combinatorial and parallel synthesis in drug discovery.