Water → 4-[4-(3-nitro-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-Nitro benzenesulfonyl chloride (122.9 mg, 0.55 mmol) was added in small portions under nitrogen to an ice-cold solution of 4-(3,4-dihydro-2H-benzo[1,4]oxazin-8-yl)-piperazine-1-carboxylic acid tert-butyl ester (161 mg, 0.504 mmol) and pyridine (88 mg, 1.11 mmol) in dichlormethane (2 mL). After 0.5 hour at ambient temperature, water was added. The organic phase was separated, washed with saturated aqueous solution of sodium bicarbonate (20 mL), dried (Na2SO4) and concentrated to give 4-[4-(3-nitro-benzenesulfonyl)-3,4-dihydro-2H-benzo[1,4]oxazin-8-yl]-piperazine-1-carboxylic acid tert-butyl ester as an oil (260 mg). MS: MH+=505.

Provenance & Evidence