Abstract

Background: Nitrogen containing heterocycle is one kind of the most important heterocycle. Among them, 1,2,4-triazolo[3,4-α]pyridine is a classic five member heterocycle fused six member heterocycle. 1,2,4-Triazolo-[3,4-α ]pyridine scaffold has been widely used in building blocks for drugs, pesticides and other fields.

Method & Objective: This review will highlight the early and recent work on the synthesis methods of diversity 1,2,4-triazolo[3,4-α]pyridines. In order to promote the development of more efficient and environment friendly reaction, this paper detailed that the synthetic procedure has been listed using many condensation agents, such as HOAc, orthoformate, Ph3PCl2, Lawesson reagent, PS-PPh3, HCOOH, POCl3, Mitsunobu reagent, Burgess reagent, IBD, metal catalyst, chloramine-T, trivalent Iodine reagent and so on. Also the 1,2,4- triazolo[3,4-α]pyridines were synthesized under microwave irradiation or conventional heat directly. This review also covers different biological activities towards various 1,2,4-triazolo-[3,4-α]pyridines including antiinflammatory activity, anti-convulsant activity, antibiotics activity, antifungal activity, herbicidal activity, fungicidal activity, anticancer activity, antivirus activity, anti- type 2 diabetes activity, etc.

Keywords: 1, 2, 4-triazolo[3, 4-α]pyridine; synthesis; cyclization; biological activity; nitrogen heterocyclic; synthetic procedure.

Graphical Abstract