Cesium carbonate → Methyl 5-(2,2,2-trifluoroethoxy)pyridine-2-carboxylate

Methyl 5-hydroxypyridine-2-carboxylate (Intermediate 224, 0.610 g, 3.59 mmol) was dissolved in DMF (5 mL), cesium carbonate (1.40 g, 4.31 mmol) and 2,2,2-trifluoroethyl trifluoromethanesulfonate (1.0 g, 4.31 mmol) were added and the mixture stirred at room temperature for 18 h. The mixture was partitioned between EtOAc (50 mL) and water (15 mL) and the aqueous layer extracted with further EtOAc (2×20 mL). The combined organic layers were dried over sodium sulfate and concentrated under vacuum. The crude material was purified by FCC, eluting with a gradient of 0-50% EtOAc in heptane to afford the title compound as a white solid (0.652 g, 77%). 1H NMR (500 MHZ, CDCl3) δ ppm 8.40 (1H, d), 8.09 (1H, d), 7.27 (1H, dd), 4.41 (2H, q) and 3.93 (3H, s).