Synthesis
General procedure for the synthesis of 2-methyl-4-bromobenzoic acid from 4-bromo-2-methylbenzonitrile: 4-bromo-2-methylbenzonitrile (1 mmol) was suspended in water (49 mL) and potassium hydroxide (50 mmol) was added. The reaction mixture was stirred overnight under reflux conditions. Upon completion of the reaction, it was cooled to room temperature and the basic aqueous solution was washed with ethyl acetate (3 x 15 mL) to remove unreacted material. Subsequently, the aqueous phase was acidified to pH < 2 with 6 M hydrochloric acid and the acidified aqueous phase was extracted with ethyl acetate (3 x 15 mL). The organic phases were combined, dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give the white solid product 2-methyl-4-bromobenzoic acid. Yield: 60%. Thin Layer Chromatography (TLC) analysis (unfolding agent: dichloromethane/methanol = 9:1): Rf = 0.46. melting point: 182 °C. 1H-NMR (300 MHz, CD3OD) δ (ppm): 7.80 (d, J = 8.4 Hz, 1H, H-6), 7.48 (s, 1H, H-3), 7.42 (d, J = 8.4 Hz, 1H, H- 5), 2.56 (s, H- 5), 2.56 (s, H- 5), 2.56 (s, H- 5). 5), 2.56 (s, 3H, CH3).
