Triethylamine → tert-butyl 4-[(2S)-3-benzyloxycarbonylamino-2-hydroxy-propyl]piperazine-1-carboxylate

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Reaction Steps

Tert-butyl 4-[(2S)-3-amino-2-hydroxy-propyl]piperazine-1-carboxylate 7c (1.24 g, 4.80 mmol) was dissolved in 60 mL of dichloromethane followed by the addition of triethylamine (970 mg, 9.60 mmol) and carbobenzoxy chloride (0.90 g, 5.28 mmol). The reaction solution was stirred for 2 hours. The resulting solution was added with 50 mL of saturated sodium bicarbonate solution and extracted with dichloromethane (50 mL×3). The combined organic phase was washed with saturated sodium chloride solution (50 mL×3), then dried over anhydrous magnesium sulfate, filtered and the filtrate was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound tert-butyl 4-[(2S)-3-benzyloxycarbonylamino-2-hydroxy-propyl]piperazine-1-carboxylate 21a (1.45 g, yield: 76.0%) as a colorless oil.

Provenance & Evidence