Synthesis
A tetrahydrofuran (THF, 0.4 M) suspension of sodium hydride (NaH, 110 mol%) was placed in a reaction vessel at 0 °C and a THF (0.5 M) solution of 2-amino-3-bromopyridine (100 mol%) was slowly added. The reaction mixture was stirred at 0 °C for 5 min, followed by warming to 23 °C and continued stirring for 5 min. The reaction vessel was transferred to a preheated oil bath and stirred at 40 °C for 1 hour. Upon completion of the reaction, the mixture was cooled to 0 °C and iodomethane (MeI, 110 mol%) was added. The reaction was maintained at 0 °C for 5 min, then warmed to 23 °C and stirred for another 5 min. Subsequently, the reaction mixture was heated to 60 °C for 12 hours. At the end of the reaction, the reaction was cooled to 23 °C, quenched with water and extracted with ethyl acetate (EtOAc). The organic layers were combined, dried over anhydrous magnesium sulfate (MgSO4) and concentrated under reduced pressure. Purification by fast column chromatography (eluent: hexane/ethyl acetate, 1:1) afforded 3-bromo-N-methylpyridin-2-amine (S6) as an orange oil in 78% yield (760.0 mg, 4.50 mmol).1H NMR (400 MHz, CDCl3) δ 8.09 (dd, J = 4.9, 1.6 Hz, 1H), 7.59 ( dd, J = 7.6, 1.6 Hz, 1H), 6.44 (dd, J = 7.6, 4.9 Hz, 1H), 3.03 (d, J = 4.9 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 155.0, 146.7, 139.3, 113.0, 105.6, 28.7. The obtained data are in agreement with the literature reports.
References
[1] Synthesis, 2007, # 24, p. 3868 - 3876
[2] European Journal of Organic Chemistry, 2017, vol. 2017, # 11, p. 1465 - 1474
[3] Tetrahedron, 2015, vol. 71, # 35, p. 5776 - 5780
