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

Participants

Reaction Conditions

Reaction Steps

Chloro-difluoro-acetic acid ethyl ester (13.8 μL, 0.10 mmol, 1.0 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 (50 mg, 0.10 mmol, 1.0 eq) in N,N-dimethylformamide (5 mL), followed by potassium carbonate (14.4 mg, 0.10 mmol, 1.0 eq). After 15 hours stirring at 70° C., solvent is evaporated and the residue is acidified with 1N hydrochloric acid aqueous solution and the resulting aqueous layer is extracted with ethyl acetate (3×10 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-difluoromethoxy-quinoxalin-2-yloxy)-ethyl]-piperidin-4-yl}-amide as a white lyophilizated powder (5 mg, 10% yield).

Provenance & Evidence