Synthesis of Pyrimido[4′,5′:4,5]thieno[2,3-c]-pyridazine Derivatives

Article abstract of DOI:10.1007/BF00807079

Convenient syntheses of 3,4-diphenyl-8-oxo-6-substituted-5,6,7,8-tetrahydropyrimido[4′, 5′:4,5]thieno[2,3-c]pyridazines (4a-g), 3,4-diphenyl-8-oxo-6-substituted-7,8-dihydropyrimido[4′,5′: 4,5]thieno[2,3-c]pyridazines (5a-g), 8-chloro-3,4-diphenyl-6-substituted-pyrimido[4′,5′:4,5]thieno [2,3-c]pyridazines (6a-g), and 3,4,6-triphenyl-8-substituted-pyrimido[4′,5′:4,5]thieno[2,3-c] pyridazines (7a-f) from 4-cyano-5,6-diphenylpyridazine-3(2H)-thione (1) via 5-amino-3,4-diphenyl-thieno[2,3-c]pyridazine-6-carboxamide (3) are reported.