Synthesis of thiadiazolinylpyrazolopyridine and pyridopyrazolotriazine derivatives

3-Diazotized aminopyrazolo[3,4-b]pyridines 2a,b used as good synthons for t he synthesis of 3-thiadiazolinylpyrazolo[3,4-b]pyridines Sa,b through their reactions with thiocyanatoacetophenone (6) and pyrido[2,3:3',4']pyrazolo[5 ,1-c][1,2,4]triazines 5a-d via their reactions with several active methylen e containing reagents: 3a,b, 12, 16, 20, 23a-d and 26a-c. All the structure s of the newly synthesized heterocyclic compounds were established by consi dering the data of IR, H-1 NMR and mass spectra in addition to the synthesi s of most newly synthesized heterocyclic compounds via other routes.