Triethylamine → methanesulfonic 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

Participants

Reaction Steps

Methanesulfonic anhydride (519 mg, 2.92 mmol, 20.0 eq) is added at 0° C. 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 (610.4 μL, 4.38 mmol, 30.0 eq). After 30 minutes 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 methanesulfonic 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 an off-white powder (25 mg, 26% yield).

Provenance & Evidence