Step 1: Preparation of 2-amino-3-bromo-6-methylpyridine
32.4 g (0.3 mol) of 2-amino-6-methylpyridine was dissolved in 28 g of concentrated hydrochloric acid. Sulfuric acid and 120 ml of water were added to the mixture and the resulting solution was subsequently cooled to 0°C in an ice water bath. Over a period of 30 minutes, 52.8 g (0.33 mol) of bromine was slowly added dropwise to the cooled solution. After the dropwise addition was completed, the reaction mixture was continued to be stirred at room temperature for 20 minutes. Subsequently, the reaction solution was neutralized with cold aqueous NaOH. The resulting solid product was collected by filtration and purified by column chromatography using dichloromethane and ethyl acetate as eluents. Finally 31 g of 2-amino-3-bromo-6-methylpyridine was obtained in 55% yield.
