SYNTHESIS OF NEW SUBSTITUTED PYRIDOPYRAZOLOTRIAZINES

Abstract

Pyrazolo[3,4-b]pyridinediazonium chlorides react with a variety of active methylenecontaining reagents (e. g., cyanoacetic acid arylidenehydrazide derivatives) to afford the corresponding 3-hydrazonopyrazolo[3,4-b]pyridine derivatives. The diazonium chlorides react with N'-acyl-2-cyanoacetohydrazide derivatives to give corresponding 3-hydrazonopyrazolopyridine derivatives. The latter affords corresponding 3-hydrazonopyrazolo[3,4-
b]pyridine derivatives on reflux in acetic acid. Diazocoupling of 2,4-dimethylpyrazolo[3,4-b]pyridinediazonium chloride with ketoester, e. g., ethyl benzoylacetate is followed by
cyclization to afford pyrido[2',3':3,4]pyrazolo[5,1-c]triazine derivative. Diazocoupling of the same dimethylpyrazolo[3,4-b]pyridinediazonium chloride with unsymmetrical β-diketone, e. g., benzoylacetone was also studied to afford the corresponding hydrazono derivative, which undergoes in situ cyclization to furnish the pyrido[2',3':3,4]pyrazolo[5,1-c]triazine derivative.

Also published in Chemistry of Heterocyclic Compounds, 2012, 48 (7), pp 1071-1077

http://link.springer.com/article/10.1007/s10593-012-1101-4