General procedure for the synthesis of 1-bromo-4-methylnaphthalene from 1-methylnaphthalene: A mixture of 1-methylnaphthalene (14.28 g, 200 mmol) and N-bromosuccinimide (NBS, 39.16 g, 220 mmol) in acetonitrile (MeCN, 300 mL) was reacted with stirring at 30-40 °C until the reaction was shown by thin layer chromatography (TLC) analysis to be was complete (typically 12 hours). Upon completion of the reaction, the mixture was cooled to room temperature, poured into water (600 mL) and extracted with dichloromethane (CH2Cl2, 500 mL x 3). The organic phases were combined and washed sequentially with 5% sodium thiosulfate (Na2S2O3) aqueous solution (200 mL), saturated sodium carbonate (Na2CO3) aqueous solution (100 mL × 3) and 5% brine (200 mL). The organic layer was dried over anhydrous sodium sulfate (Na2SO4) and the solvent was removed by rotary evaporation to obtain the crude product. Purification by column chromatography afforded the target product 1-bromo-4-methylnaphthalene (15) as a colorless oil in a yield of 42.01 g (98% yield).1H-NMR (DMSO-d6, 400 MHz) δ: 8.14-8.16 (m, 1H), 8.07-8.09 (m, 1H), 7.76 (d, J = 7.6 Hz, 1H), 7.66 -7.70 (m, 2H), 7.30 (d, J = 7.6 Hz, 1H), 2.63 (s, 3H).
