Three-component, one-pot synthesis of pyrimido[4,5-b]-quinoline and pyrido[2,3-d]pyrimidine derivatives

Reaction of 6-amino-2-methylthiouracil and 6-amino-1,3-dimethyluracil with equimoler amounts of cyclic ketones or cyclic 1,3-diketones and the appropriate aromatic aldehydes yielded regioselectivity a series of polycyclic pyrimido[4,5-b]quinoline and pyrido[2,3-d]dipyrimidine derivatives in good yields.