To a solution of 4-iodo-2-methylbenzoic acid (2 g, 7.62 mmol) in methanol (20 mL) at 0 °C was slowly added thionyl chloride (1.5 mL, 10.87 mmol). The reaction mixture was heated to reflux and stirred for 6 hours. Upon completion of the reaction, the solvent was removed by distillation and the residue was diluted with ethyl acetate (50 mL). The organic phase was washed sequentially with water (100 mL) and sodium bicarbonate solution (50 mL) and then dried over anhydrous sodium sulfate. The organic phase was concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography (eluent: 10% ethyl acetate in hexane solution) to afford methyl 4-iodo-2-methylbenzoate (1.8 g, 6.55 mmol, 85.7% yield) as a brown oily liquid.
