Diisopropylethylamine → 2-((2R)-2-(N-((2R)-2-(N-tert-Butoxycarbonyl-N-methylamino)-3-(2-naphthyl) propionyl)-N-methylamino)-3-phenylpropionylamino)-1,1-dimethylethyl acetate

Participants

Reaction Conditions

Reaction Steps

(2R)-2-(N-(tert-Butoxycarbonyl)-N-methylamino)-3-(2-naphthyl)propionic acid (373 mg, 1.13 mmol) was dissolved in N,N-dimethylformamide (2 ml) and dichloromethane (2 ml). 1-Hydroxy-7-azabenzotriazole (153 mg, 1.13 mmol) was added. The solution was cooled to 0° C. N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (217 mg, 1.13 mmol) was added. The reaction mixture was stirred for 10 min at 0° C. 1,1-Dimethyl-2-((2R)-2-methylamino-3-phenylpropionylamino)-ethyl acetate (301 mg, 1.03 mmol) was dissolved in dichloromethane (2 ml) and added. Ethyldiisopropylamine (0.18 ml, 1.03 mmol) was added. The reaction mixture was stirred for 20 h, while it was warming up to room temperature. It was diluted with ethyl acetate (100 ml) and washed with 1N hydrochloric acid. The aqueous phase was extracted with ethyl acetate (3×30 ml). The combined organic layers were washed with saturated sodium hydrogen carbonate solution (100 ml) and dried over magnesium sulfate. The solvent was removed in vacuo. The crude product was purified by flash chromatography on silica (85 g), using ethyl acetate/heptane (1:1) as eluent, to give 547 mg of 2-((2R)-2-(N-((2R)-2-(N-tert-butoxycarbonyl-N-methylamino)-3-(2-naphthyl)propionyl)-N-methylamino)-3-phenylpropionylamino)-1,1-dimethylethyl acetate.

Provenance & Evidence