Cesium carbonate → 3-Bromo-6-(4-bromo-3-formyl-phenoxy)-pyridine-2-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

To a solution of 3-bromo-6-chloro-pyridine-2-carboxylic acid ethyl ester (22, 8.0 g, 30.24 mmol) and 2-bromo-5-hydroxy-benzaldehyde (7.29 g, 36.29 mmol) in DMF (100 mL) was added cesium carbonate (22.6 g, 69.55 mmol). The resulting mixture was heated at 80° C. overnight. DMF was removed under reduced pressure, and the residue was diluted with EtOAc (200 mL), washed with water (2×50 mL) and brine (50 mL) solution. The combined organic layers were dried over Na2SO4, filtered, and concentrated to give crude product which was purified by column chromatography (Silica gel 20% EtOAc in hexane) to yield title compound 23 (4.0 g, 31%) as transparent oil. 1H NMR 400 MHz (DMSO-d6) δ: 10.18 (s, 1H), 8.27 (d, J=8.6 Hz, 1H), 7.87 (d, J=7.6 Hz, 1H), 7.65 (s, 1H), 7.51 (dd, J=8.7, 2.9 Hz, 1H), 7.26 (d, J=8.9 Hz, 1H), 4.29 (q, J=7.1 Hz, 2H), 1.25 (t, J=7.0 Hz, 3H); MS (ES) m/z: 430 (M+1)+.

Provenance & Evidence