Potassium Carbonate → [3-(2-{4-[(3-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carbonyl)-amino]-piperidin-1-yl}-ethoxy)-quinoxalin-6-yloxy]-acetic acid methyl ester

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Reaction Steps

Bromo-acetic acid methyl ester (20.0 μL, 0.22 mmol, 1.05 eq) is added at room temperature to a stirred solution of 3-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carboxylic acid {1-[2-(7-hydroxy-quinoxalin-2-yloxy)-ethyl]-piperidin-4-yl}-amide (100 mg, 0.21 mmol, 1.0 eq) in N,N-dimethylformamide (2 mL), followed by potassium carbonate (57.6 mg, 0.42 mmol, 2.0 eq). After 5 hours stirring at room temperature, solvent is evaporated and the residue is extracted with dichloromethane (3×5 mL) and water (5 mL). The combined organic layers are dried over sodium sulfate, filtered and concentrated to give a residue that is purified by preparative HPLC to afford [3-(2-{4-[(3-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carbonyl)-amino]-piperidin-1-yl}-ethoxy)-quinoxalin-6-yloxy]-acetic acid methyl ester as a white powder (8 mg, 6% yield).

Provenance & Evidence