Synthesis, reactions and characterization of 2-methylthionicotino-nitrile, pyrazolopyridine and pyridopyrazolotriazine derivatives

Abstract

4,6-Diaryl-1H-pyrazolo[3,4-b]pyridin-3-amines 4a-c were
obtained in very pure state and used as the good starting
materials for the present study. Compound 4a diazotized to give the corresponding diazonium salt 11 and also, reacted with 2-bromo-1-phenylethanone to give the corresponding pyrazolo[3,4-b]pyridin-2-yl)-1-phenylethanone derivative 7 which in turn, used for the preparation of the hydrazone and formamide derivatives 8 and 10 respectively through its reaction with hydrazine hydrate and formic acid respectively. Compound 11 was used for the preparation of pyridopyrazolotriazine derivatives via its coupling with several active –CH2- containing compounds.
Considering the data from IR, 1H NMR, the mass spectra and elemental analyses the chemical structures of the newly synthesized heterocyclic compounds were elucidated.