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

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Reaction Steps

Acetyl chloride (11.4 μL, 0.16 mmol, 1.1 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 (70 mg, 0.15 mmol, 1.0 eq) in N,N-dimethylformamide (2 mL), followed by triethylamine (40.7 μL, 0.29 mmol, 2.0 eq). After 1 hour 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 acetic acid 3-(2-{4-[(3-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carbonyl)-amino]-piperidin-1-yl}-ethoxy)-quinoxalin-6-yl ester as a white powder (35 mg, 41% yield).

Provenance & Evidence