Synthesis of polynuclear heterocyclic compounds derived from thieno [2,3-d] pyrimidine derivatives

Reaction of 2-hydrazino-3-methyl-3,4-dihydrothieno[2,3-d]pyrimidin-4-one derivatives 2a,b with aliphatic acids afforded the thienotriazolopyrimidinone derivatives 3a-d, with nitrous acid yielded tetrazolothienopyrimidinone derivatives 4a,b and with carbon disulphide furnished 3-mercaptothienotriazolopyrimidinone derivatives 5a,b. Also, 2a,b reacted with aldehydes to afford the arylhydrazones 6a-f which cyclized into thienotriazolopyrimidinone derivatives 7a-f. Furthermore, 2a,b condensed with ethyl acetoacetate and ethyl cyanoacetate to afford 2-(1-pyrazolyl) derivatives 9a,b and 10a,b, respectively. On the other hand, 2-hydrazino derivatives 2a,b condensed with a-halo-ketones to yield thienpyrimidotriazinone derivatives 11a,b and with beta-diketones, to form 2-(1-pyrazolyl) derivatives 12a-f.