SYNTHESIS OF SOME NEW 3,5,7-TRISUBSTITUTED PYRAZOLO|4,3-e|1,2,4-TRIAZINES

This work deals with synthesis of some new 3,5-diaryl-7-(4-sulphophenyl)-pyrazolo [4,3-e]1,2,4-triazines and semicarbazones of 3-phenyl-5-substbenzoyl-6-oxo-1,6-dihydro1,2,4-triazines. Introduction Some reactions of active methylene group of 3-substituted-5-arylmethylene-6-oxo1,6-dihydro-1,2,4-triazines 1 were already described in previous communications. The chloration with phosphorus pentachloride leads to the dichloroderivates 2 and coupling with aryldiazonium salts leads to arylhydrazones 3. The mentioned works 4 also describe cyclization of the arylhydrazones 3 to 3,5,7-trisubstituted pyrazolo[4,3-e]1,2,4-triazines. Some pyrazolo[4,3-e]1,2,4-triazines have been found as extracellular pigments of some microorganisms of the genus Pseudomonas fluorescens and Nostoc spongioformae. These biogenic compounds showed wide antibiotic and antitumoric activities . In this work we tried to put hydrophilic groups into the pyrazolo[4,3-e]1,2,4triazine skeleton. We performed copulation reaction on active methylene group of 1 with diazoated sulphanilic acid and cyclization in phosphorus oxychloride to 3,5-diaryl7-(4-sulphophenyl)-pyrazolo[4,3-e]1,2,4-triazines. We also tried to put karbamoyl group into the pyrazolo[4,3-e]1,2,4-triazine skeleton. Smoothly proceedings reaction of 2 with semicarbazide gives semicarbazones of 3-substituted-5-substbenzoyl-6-oxo-1,6-