General procedure for the synthesis of 2,4-dimethylbenzyl bromide from (2,4-dimethylphenyl)methanol:
1. to a solution of diisopropyl ether (100 mL) of (2,4-dimethylphenyl)methanol (10.77 g) was slowly added phosphorus tribromide (4.90 mL) at 0 °C.
2. The reaction mixture was stirred at room temperature for 1 hour.
3. Upon completion of the reaction, water was added to the mixture and extracted with ethyl acetate.
4. The organic phases were combined and washed twice with water, saturated aqueous sodium bicarbonate and saturated brine in that order.
5. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give 2,4-dimethylbenzyl bromide as a colorless oil (15.5 g, quantitative yield).
6. The structure of the product was confirmed by 1H-NMR (CDCl3): δ 2.30 (3H, s), 2.37 (3H, s), 4.50 (2H, s), 6.96-6.99 (2H, m), 7.17-7.19 (1H, m).
