Microwave assisted practical synthesis of 4-imino-3-phenyl-3,4-dihydro-1H-chromeno[2,3-d]pyrimidine-2(5H)-thione derivatives and exploration of their biological activities

The synthesis of a series of new 4-imino-3,4-dihydro-1H-chromeno[2,3-d]pyrimidine-2(5H)-thiones 6(a-f) without substituent in C-5 position using microwave dielectric heating is reported.These new compounds were obtained in three steps with good overall yields (21-50%).