m-Chloroperbenzoic acid → 3-Bromo-4-(cyclopropylmethoxy)pyridine 1-oxide

To a solution of 3-Bromo-4-cyclopropylmethoxy-pyridine (Example 53a, 1 g, 4.38 mmol) in dichloromethane was added 3-Chloro-benzenecarboperoxoic acid (1.47 g, 6.58 mmol) and the reaction mixture was stirred at room temperature for 3 hours. The reaction mixture was poured into 250 mL dichloromethane and extracted with 75 mL of an aqueous solution 1M sodium bicarbonate. The organic layers was collected, dried over sodium sulfate and concentrated in vacuo. The crude material was purified by flash chromatography on silica eluting with a dichloromethane/methanol gradient to yield the title compound (954 mg, 89%) as a white solid. MS (ESI, m/z): 244.2 (M+H+).