Synthesis
Step 1: Synthesis of methyl 5-bromo-6-chloronicotinate (61). A mixture of 5-bromo-6-chloronicotinic acid (60) (0.2 g, 0.84 mmol), potassium carbonate (K2CO3) (0.3 g, 2.1 mmol) and iodomethane (0.178 g, 1.2 mmol) in N,N-dimethylformamide (DMF) (10 mL) was stirred for 16 h at 0 °C and subsequently raised to room temperature. Upon completion of the reaction, the reaction mixture was diluted with water (20 mL) and extracted with ethyl acetate (EtOAc) (2 x 20 mL). The organic phases were combined and washed sequentially with saturated aqueous sodium bicarbonate (NaHCO3) (20 mL) and brine (2 x 20 mL), dried over anhydrous sodium sulfate (Na2SO4) and concentrated to afford the target product methyl 5-bromo-6-chloronicotinate (61) (0.2 g, 94.7% yield).
