Synthesis of thiazole, triazole, pyrazolo[3,4-b]-pyridinyl-3-phenylthiourea, aminopyrazolo[3,4-b]pyridine derivatives and their biological evaluation

The pyrazolopyridine derivatives la,b reacted with phenylisothiocyanate (2) , nitrous acid and cinnamonitrile. derivatives 5a,b to afford the correspon ded pyrazolo[3,4-b]-pyridinyl-3-phenylthiourea derivatives 3a,b, 3-diazotiz ed aminopyrazolo[3,4-b]-pyridine derivatives 4a,b and Schiff bases 7a-d in a respective manner Compounds 3a,b, Jab and 7a-d were taken as the starting materials for the present study owing to the presence of more than one act ive site. Compounds 3a,b reacted with the halogen-containing reagents e.g. 11a,b, 13 and 15 to Five the corresponded thiazole derivatives 12a-d, 14a,b and 16a,b respectively. Compounds Ja,b coupled with the active hydrogen-co ntaining reagents 17a-j to afford the corresponding 3-hydrazino derivatives 18a-t which could be cyclized to give the corresponding triazines 19a-t re spectively. Compounds 7a-d reacted with thioglycolic acid (9) to give the c orresponding thiazole derivative 10a-d in a good yield. The assigned struct ures of the newly synthesized compounds are based on their elemental analys es, IR, H-1 NMR and mass spectra. The biological activity of some of thee c ompounds was tested.