Ethyl bromoacetate → {2,5-Dichloro-4-[3-(4-cyclopropyl-3,4-dihydro-2H-quinoxaline-1-carbonyl)-pyridin-4-yloxy]-phenoxy}-acetic acid ethyl ester

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Reaction Steps

To a solution of 0.15 g (0.33 mmol) (4-cyclopropyl-3,4-dihydro-2H-quinoxalin-1-yl)-[4-(2,5-dichloro-4-hydroxy-phenoxy)-pyridin-3-yl]-methanone (Example 57) in 2 mL N,N-dimethylformamide was added 0.016 g (0.37 mmol) sodium hydride (60% dispersion in mineral oil, Aldrich, CAS RN 7646-69-7). The reaction mixture was stirred for 15 min. at room temperature before 0.04 mL (0.36 mmol) ethyl bromoacetate (commercially available, CAS RN 105-36-2) were added. After stirring at room temperature for 3 hours the solution was poured on water and extracted three times with ethyl acetate. The combined organic layers were washed with water and brine, dried over magnesium sulfate, filtered, treated with silica gel and evaporated. The resulting powder was purified by silica gel chromatography using a MPLC system (10 g silica gel column, CombiFlash Companion, Isco Inc.) eluting with a gradient of n-heptane:ethyl acetate (100:0 to 30:70) to give 0.144 g (81%) of the desired compound as a light yellow foam. MS (ESI): m/z=542.123 [M+H]+.

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