Bromoisobutyric acid (4.17 g, 25 mmol) was dissolved in a solution of concentrated sulfuric acid (0.75 mL) and methanol (50 mL) and stirred under reflux for 2 h. The solution was then cooled to room temperature and concentrated under vacuum. The residue was dissolved in diethyl ether and washed with 10% aqueous sodium bicarbonate, washed with brine, dried under magnesium sulfate, and concentrated again under vacuum. A colorless oil was obtained (4.2 g, 23 mmol, 93% yield) 1H NMR (300 MHz, CDCl3) δ(ppm): 3.78 (s, 3H), 1.93 (s, 6H)
