Synthesis of some new 4-imino-3,5,7-trisubstituted-pyrido[2,3-d]pyrimidine-2(1H)-thiones

The synthesis of 4-imino-3,5,7-trisubstituted-pyrido2,3-d]pyrimidine-2(1H)-thiones is described. The elemental analysis, ir and nmr spectral data confirm the structure of the products.