The synthesis and properties of pyridazino[4,3-e] -as-triazines and pyridazino[4,5-e] -as-triazines,two novel condensed pyridazine ring systems

The compounds prepared in the novel pyridazino4,3-e]-as-triazine ring system are: 8-chloro-4-methyl-3,4-dihydropyridazino4,3-e]-as-triazine ( 21 ), 8-chloro-2,4-dimethyl-3,4-dihydropyridazino4,3-e]-as-triazine ( 23 ), 8-chloro-2-ethyl-4-methyl-3,4-dihydropyridazino4,3-e]-as- triazine ( 24 ), 4-methyl-3,4-dihydropyridazino4,3-e]-as-triazine-8-thione ( 25 ), 4-methyl-3,4-dihydropyridazino4,3-e]-as-triazine ( 26 ), 2,4-dimethyl-3,4-dihydropyridazino4,3-e]-as-triazine ( 27 ), and 2-ethyl-4-methyl-3,4-dihydropyridazino4,3-e]-as-triazine ( 28 ). In the novel pyridazino4,5-e]-as-triazine ring system the following compounds were prepared: 1,2-dihydropyridazino4,5-e]-as-triazine ( 31 ), 3-methyl-1,2-dihydropyridazino4,5-e]-as-triazine ( 32 ), 3-ethyl-1,2-dihydropyridazino4,5-e]-as-triazine ( 33 ), and 1-methyl-1,2-dihydropyridazino4,5-e]-as-triazine ( 35 ). The preparation of a number of previously unreported intermediates and compounds for structure proof are also described.