To a stirred dichloromethane (DCM) solution of methylamine hydrochloride (0.13 g, 1.97 mmol) was sequentially added N,N-diisopropylethylamine (DIPEA, 0.52 mL, 2.95 mmol) and 4-bromobenzenesulfonyl chloride (0.25 g, 0.98 mmol), and the reaction was continuously stirred for 16 h at room temperature. The reaction progress was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was quenched with deionized water and extracted with dichloromethane (DCM). The organic layers were combined, dried with anhydrous sodium sulfate and concentrated under reduced pressure to afford the target product N-methyl-4-bromobenzenesulfonamide (0.220 g, 89.74% yield) as a yellow semi-solid. Mass spectrometry (MS) analysis showed that [M-1] m/z 248.0.
