Benzoyl chloride → 7-Bromo-2-phenyl-[1,2,4]triazolo[1,5-A]pyridine

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Reaction Steps

1,2-Diamino-4-bromopyridinium 2,4,6-trimethylbenzenesulfonate (15.6 g, 40.2 mmole) in pyridine (106 ml) is heated overnight at 100° C. with benzoyl chloride (9.4 ml, 80 mmole) giving a redbrown solution and after 2 hrs a brown suspension. The reaction mixture is concentrated in vacuo and the residue is triturated for 2.5 hr in sat. aqueous ammonium chloride solution (300 ml), while neutralizing to pH 6-7 with sat. aqueous sodium bicarbonate solution. The solid is collected by filtration, washed with water (40 ml) and dried affording 7-bromo-2-phenyl-[1,2,4]triazolo[1,5-a]pyridine (6.78 g, 61.6%) as an off-white solid. mp.: 189-191° C. MS: m/z=276.1, 274.2 (M+H+).

Provenance & Evidence