General procedure for the synthesis of 2-bromo-3-methylpyridine nitrogen oxides from 2-bromo-3-methylpyridine: 3-chloroperbenzoic acid (bOg) was slowly added to a stirring solution of 2-bromo-3-methylpyridine (50 g) in dichloromethane (500 mL) at room temperature. The reaction mixture was continuously stirred at room temperature for about 12 hours and then filtered. The filtrate was then quenched by slow pouring into saturated sodium thiosulfate solution. The quenched reaction mixture was continued to be stirred at room temperature for about 1 hour. Afterwards, the organic and aqueous layers were separated and the aqueous layer was extracted twice with dichloromethane. All organic layers were combined, washed sequentially with water and saturated brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure at 40 °C. The crude product was purified by column chromatography (eluent: ethyl acetate solution of 5-7% methanol) to afford 33 g of the target product 2-bromo-3-methylpyridine nitride in 60% yield. The product characterization data were as follows: 1H NMR (300 MHz, CDCl3): δ 8.30-8.29 (m, 1H), 7.14-7.12 (m, 2H), 2.47 (s, 3H); IR (cm-1): 3382, 3051, 1670, 1436, 1410, 1275, 1240, 1067, 958, 786,. 695, 599; MS (ESI): [M + H]+ m/z 188.09.
