3-Bromo-2-methylpyridine

109-06-8

38749-79-0

The general procedure for synthesizing 2-methyl-3-bromopyridine from 2-methylpyridine was as follows: 2-methylpyridine (46.6 g) was slowly added dropwise to aluminum chloride (200 g) with reference to the method of Example 182, and the mixture was stirred continuously at 100°C. Maintaining the same temperature, bromine (40.0 g) was slowly added dropwise to the mixture over a period of 1 hour, followed by continued stirring for 30 minutes. Upon completion of the reaction, the mixture was cooled and poured into ice water, followed by addition of concentrated hydrochloric acid until the mixture was acidified. The resulting solution was washed with ethyl acetate and the aqueous layer was alkalized with 8 mol/L aqueous sodium hydroxide. The alkalized aqueous layer was extracted with ether and the extract was washed with saturated brine and dried with anhydrous sodium sulfate. Subsequently, the extract was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (eluent: hexane-ether=10:1) to afford 2-methyl-3-bromopyridine as a colorless oil (yield 5.09 g, 12% yield). The structure of the product was confirmed by 1H-NMR (CDCl3): δ 2.67 (3H, s), 6.98-7.03 (1H, m), 7.78-7.82 (1H, m), 8.40-8.44 (1H, m).