Ethoxalyl chloride → Ethyl 7-bromo-(1,2,4)triazolo(1,5-a)pyridine-2-carboxylate

Participants

Reaction Steps

A mixture of 1,2-diamino-4-bromopyridinium 2,4,6-trimethylbenzenesulfonate (4.18 g, 10.8 mmol) and ethyl 2-chloro-2-oxoacetate (2.4 ml, 21.5 mmol) in pyridine (25 ml) is heated for 18 hours to 100° C. The solvent is evaporated and the orange residue triturated with sat. aqueous sodium hydrogencarbonate solution for 2 hours. The solid is collected by filtration, washed several times with water and dried affording ethyl 7-bromo-[1,2,4]triazolo[1,5-a]pyridine-2-carboxylate (1.759 g, 60.5%) as a light pink solid. mp.: 158-160° C. MS: m/z=270.2 (M+H+).

Provenance & Evidence