Sodium hydride → 3-[4-(2,4-Difluoro-phenyl)-piperazine-1-carbonyloxymethyl]-morpholine-4-carboxylic acid tert-butyl ester

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Reaction Steps

3-Hydroxymethyl-morpholine-4-carboxylic acid tert-butyl ester (Intermediate 7; 250 mg, 0.76 mmol) in THF (5 mL) was added dropwise to a suspension of NaH (60% dispersion in oil, prewashed with hexane; 138 mg, 3.45 mmol) in anhydrous THF (5 mL) at 0° C. and stirred under nitrogen for 35 minutes. 4-(2,4-Difluorophenyl)-piperazine-1-carboxylic acid 4-nitrophenyl ester (Intermediate 12; 501 mg, 1.38 mmol) was added and the reaction mixture was stirred at room temperature overnight. The reaction mixture was quenched with the addition of aqueous NaHCO3 (0.5 mL) at 0° C. and the solvents removed in vacuo. The residue was suspended between aq Na2CO3 (20 mL) and EtOAc (20 mL). The aqueous phase was extracted with EtOAc (2×20 mL). The combined organic layers were washed with aq Na2CO3 (20 mL), dried (MgSO4) and the solvent removed in vacuo. The residue was purified by column chromatography (normal phase, Apollo silica, 1% MeOH in DCM) and the solvents were removed in vacuo to give 3-[4-(2,4-difluoro-phenyl)-piperazine-1-carbonyloxymethyl]-morpholine-4-carboxylic acid tert-butyl ester (170 mg, 34%).

Provenance & Evidence