General procedure for the synthesis of 2,3-dibromo-4-methylpyridine from 2-amino-3-bromo-4-methylpyridine: Bromine (0.35 mL, 6.8 mmol) was slowly added dropwise to a solution of 3-bromo-4-methylpyridin-2-amine (0.44 g, 2.4 mmol) dissolved in 48% hydrobromic acid (3 mL) to form an orange slurry at -10 °C. 5 minutes later, sodium nitrite (0.47 g, 6.8 mmol) dissolved in water (1.5 mL) was added dropwise over 5 minutes. The reaction mixture was slowly warmed to 10 °C, held for 3.5 h, then cooled to 0 °C and the reaction was quenched with 10 N sodium hydroxide solution until the pH reached about 12. The resulting orange slurry was extracted with dichloromethane (3 x 50 mL), the organic phase was dried with anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give an orange to brown solid. Purification by silica gel column chromatography (eluent: hexane/ether, 7:3, v/v) afforded 2,3-dibromo-4-methylpyridine (0.28 g, 47% yield) as a light yellow solid.1H NMR (CDCl3) δ 2.48 (s, 3H), 7.11 (d, 1H, J = 6.0 Hz), 8.16 (d, 1H, J = 6.0 Hz).
