As shown in Step 5-i of Scheme 5, 5-bromo-2-chloro-3-methoxypyridine (1.0 g, 4.5 mmol, prepared as in Compound 1003 in Example 2, starting material 3-bromo-5-methoxypyridine) was mixed with an ethanolic solution of sodium ethoxide (5.05 mL, 21% w/v, 13.5 mmol). The reaction mixture was microwaved at 100 °C for 20 min. Upon completion of the reaction, water was added and ethanol was removed by distillation under reduced pressure. The resulting aqueous solution was extracted with dichloromethane (DCM) and ether and the combined organic phases were dried with anhydrous magnesium sulfate (MgSO). After filtration, the volatile solvent was removed by reduced pressure distillation to afford 5-bromo-2-ethoxy-3-methoxypyridine (compound 1016, 0.72 g, 69% yield). Mass spectrometry analysis (ESMS) showed the (M + H) peak of 232.32/234.23.
