Water → 4-[6-chloro-4-(3-methanesulfonyl-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazin-8-yl]-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

3-Methanesulfonyl-benzenesulfonyl chloride (80 mg, 0.314 mmol) was added in small portions under nitrogen to an ice-cold solution of 4-(6-chloro-3,4-dihydro-2H-benzo[1,4]oxazin-8-yl)-piperazine-1-carboxylic acid tert-butyl ester (101 mg, 0.285 mmol) and pyridine (50 mg, 0.628 mmol) in dichlormethane (2 mL). After 1.5 hours at ambient temperature, water was added. The layers were separated and the organic phase was washed with saturated aqueous solution of sodium bicarbonate (20 mL), dried (Na2SO4) and concentrated to give 4-[6-chloro-4-(3-methanesulfonyl-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazin-8-yl]-piperazine-1-carboxylic acid tert-butyl ester as an oil (150 mg, 91%).

Provenance & Evidence