Synthesis of Thiazole, Triazole, Pyrazolo[3,4-b]-Pyridinyl-3-Phenylthiourea, Aminopyrazolo[3,4-b]Pyridine Derivatives and Their Biological Evaluation

Abstract

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

Key Words:

• Phenylisothiocyanate
• Thiazole
• Triazole
• Pyrazolo[3,4-b]pyridinyl-3-phenylthiourea and Aminopyrazolo[3,4-b]pyridine