Fusion reactions of N-heterocyclic moieties to thiopyrano[4',3':4,5]thieno[2,3-d]pyrimidines

Derivatives of the novel heterocyclic parent systems imidazolo[1,2-a] thiopyrano [4',3':4,5]thieno[2,3-d]-pyrimidine (B) and thiopyrano[4',3':4,5]thieno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidine (C) have been synthesized by fusing pyrimidine moieties to 2-amino-4,7-dihydro-5H-thieno[2,3-c]thiopyran-3-carboxylic acid ethyl ester (1) and -3-carbonitrile (10), followed by cyclization reactions of the title intermediates A thus obtained.