Hydrogen Bromide → 5-Bromo-2-methylbenzonitrile

Participants

Reaction Conditions

Reaction Steps

Conc. sulfuric acid (60 mL) is added to sodium nitrite (5.75 g, 83.4 mmol). The temperature rises to 70° C. and solution is effected. After cooling to 20-40° C., the above solution is added dropwise to a mechanically stirred solution of 5-amino-2-methylbenzonitrile (10.0 g, 75.8 mmol) in acetic acid (150 mL). The temperature is maintained at 20-40° C. throughout the addition. The reaction mixture is cooled to 16-20° C. and a solution of cuprous bromide (24 g, 167 mmol) in conc. hydrobromic acid (150 mL) is added keeping the temperature between 16-20° C. After 45 min, the reaction mixture is poured onto ice (500 g) and the solids are collected by filtration then dissolved in dichloromethane (600 mL), washed with brine, dried, filtered and concentrated to give 5-bromo-2-methylbenzonitrile (see also, Dressler, J. et al. EP 0 594 019) (11.5 g, 77%) as a brown solid. 1H NMR (CDCl3, δ ppm): 7.72 (1H, s), 7.60 (1H, dd), 7.20 (1H, dd), 2.50 (3H, s).

Provenance & Evidence