Hydrogen Bromide → 1-(4-Bromo-3-methylphenyl)-1,2,4-triazole

Participants

Reaction Steps

4-(1,2,4-Triazol-1-yl)-2-methylaniline (D62, 0.55 g) in 48% HBr (10 ml) at -5° C. was stirred while sodium nitrite (0.3 g) was added portionwise over approximately 5 minutes to give a brown sludge which was left for a further 15 minutes. During this time, copper (1) bromide (0.63 g) was heated under reflux in 48% HBr (2 ml) under argon. The brown sludge was added to it portionwise over 5 minutes and the resulting black reaction mixture heated under reflux for a further 1 minute. After cooling slightly, the mixture was poured gently into 10% aqueous ethylenediamine solution to give a purple solution. Ethyl acetate extraction gave the title compound which was purified by chromatography on silica using 4-10% pentane/ethyl acetate as eluant (0.77 g, 73%) Mass spec (CI) MH+ 238, 240.

Provenance & Evidence