Formation of novel pyrido[3′,2′:4,5]thieno [2,3-e][1,2,4] triazolo[4,3-c] pyrimidines and their acyclic C-nucleosides analogues: Synthesis of 3-(alditol-1-yl)pyridothienotriazolopyrimidines

A series of the hydrazones were prepared by the reaction of 4-hydrazino-7,9-dimethylpyrido[3′,2′:4,5]thieno [2,3-d]pyrimidine (1) with monosaccharides, and their acetylation was studied. The oxidative cyclisation of the hydrazones 3a-c gave 3-(Alditol-1-yl)- pyridothienotriazolopyrimidenes 5a-c, whose acetylation was carried out. Also, oxidative cyclisation of arylidenes 7a,b gave the pyridothienotriazolopyrimidines 8a,b.