Ethyl Bromide → 3-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carboxylic acid {1-[2-(7-ethoxy-quinoxalin-2-yloxy)-ethyl]-piperidin-4-yl}-amide

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Reaction Conditions

Reaction Steps

Ethyl bromide (12.8 μL, 0.17 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 (75 mg, 0.16 mmol, 1.0 eq) in N,N-dimethylformamide (2 mL), followed by potassium carbonate (28.1 mg, 0.20 mmol, 1.3 eq). After 3 hours stirring at 60° C., 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-oxo-3,4-dihydro-2H-benzo[1,4]thiazine-6-carboxylic acid {1-[2-(7-ethoxy-quinoxalin-2-yloxy)-ethyl]-piperidin-4-yl}-amide as a white powder (15 mg, 18% yield).

Provenance & Evidence