Diisopropylethylamine → rac-[(3R,4S)-4-(3,4-Dichloro-phenyl)-1-(tetrahydro-pyran-4-carbonyl)-pyrrolidin-3-yl]-methyl-carbamic acid 4-fluoro-phenyl ester

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Reaction Steps

To a solution of tetrahydropyran-4-yl-carboxylic acid (51 mg, 0.39 mmol) in DMF (1 mL) was added ambient temperature 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (114 mg, 0.36 mmol) and N,N-diisopropyl ethyl amine (125 mg, 0.97 mmol). After stirring for 15 min at this temperature a solution of rac-[(3R,4S)-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid 4-fluoro-phenyl ester (124 mg, 0.32 mol) in DMF (1 mL) was added and stirred for 20 h at ambient temperature. The reaction mixture was diluted with ethyl acetate (10 mL) and washed with aqueous sodium carbonate (1 M, 10 mL), water (10 mL) and brine (10 mL). The aqueous layers were extracted with ethyl acetate (10 mL) and the combined organic layers were dried over sodium sulfate and concentrated. Purification by chromatography (SiO2, ethyl acetate:methanol=98:2 to 85:15) afforded the title compound (92 mg, 57%) as a white oil. MS m/e: 495.3 [M]+.

Provenance & Evidence