453511-35-8Relevant academic research and scientific papers
Syntheses of some new azolopyrido-[4′,3′:4,5]thieno[2,3-d]pyrimidines
Ahmed, Essam Kh.
, p. 280 - 286 (2002)
Diethyl2-[(ethoxythioxomethyl)amino]4,5,6,7-tetrahydrothieno[2,3-c]-pyridin e-3,6-dicarboxylate 2, prepared from diethyl 2-isothiocyanato-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3,6-dicarboxylate 1 by boiling in anhydrous ethanol, was converted into pyrido[4′,3′:4,5]thieno[2,3-d]pyrimidine derivatives 3, 4 by treatment with hydrazine hydrate. The tetracyclic systems imidazo[1,2-a]pyrido-[4′,3′:4,5]-thieno[2,3-d]pyrimidine 9 and pyrido[4′,3′:4,5]-thieno[2,3-d][1,3]thiazolo-[3,2-a]pyrimidine 10 were synthesized by the reaction of 2 with 1,2-diaminoethane and aminoethanethiol, respectively. The hydrazino derivative 4 underwent cyclization reactions with orthoesters and nitrous acid to give the corresponding pyrido[4′,3′:4,5]thieno[2,3-d][1,2,4]triazolo[1,5-a]pyrimidines 5, 6 and pyrido[4′,3′:4,5]thieno[3,2-e][1,2,3,4]tetrazolo[1,5-a]pyrimidine 8, respectively. Moreover, reactions of 3 with cyanogen bromide, N-carbethoxyhydrazine, carbon disulfide, and ethyl chloroformate resulted in the formation of the new pyrido[4′,3′:4,5]thieno[2,3-d][1,3,4]thiadiazolo-[3,2-a]pyrimidine derivatives 12-15.
