Acetic Anhydride → 3-((2R)-2-(N-tert-butoxycarbonyl-N-methylamino)-3-phenylpropionylamino)propyl acetate

Participants

Reaction Steps

A solution of N-((1R)-1-(3-hydroxypropylcarbamoyl)-2-phenylethyl)-N-methyl-carbamic acid tert-butylester (965 mg, 2.86 mmol) in dichloromethane (10 mL) was cooled to 0° C. 4-(dimethylamino)pyridine (35 mg, 0.29 mmol), triethylamine (0.60 mL, 4.29 mmol), and acetic acid anhydride (0.32 mL, 3.43 mmol) were added. The reaction mixture was stirred for 5 hours, while it was warming slowly to room temperature. The reaction mixture was diluted with dichloromethane (100 mL) and washed with 10% sodium hydrogensulfate solution. The aqueous phase was extracted with dichloromethane (2×50 mL). The organic phases were combined and washed with saturated sodium hydrogen carbonate solution. They were dried over magnesium sulfate. The solvent was removed in vacuo, and the crude product was purified by flash chromatography on silica (90 g) with ethyl acetate/dichloromethane (1:3 to 1:1) to give 890 mg of 3-((2R)-2-(N-tert-butoxycarbonyl-N-methylamino)-3-phenylpropionylamino)propyl acetate.

Provenance & Evidence