Diisopropylethylamine → (2S)-2-([N-methyl-N-{(1R)-1-(N-methyl-N-[(1R)-1-(methylcarbamoyl)-2-phenylethyl]carbamoyl)-2-(2-naphthyl)ethyl}carbamoyl]methoxymethyl)pyrrolidine-1-carboxylic acid tert-butylester

Participants

Reaction Steps

To a solution of (2S)-2-(((carboxy)methoxy)methyl)-pyrrolidin-1-carboxylic acid tert-butylester (1.2 g, 4.5 mmol) in dichloromethane (20 ml) were added 1-hydroxy-7-azabenzotriazole (612 mg, 4.5 mmol) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (950 mg, 4.95 mmol) and the mixture was stirred for 30 min. (2R)-N-Methyl-2-methylamino-N-((1R)-1-(methylcarbamoyl)-2-phenylethyl)-3-(2-naphthyl)propionamide (605 mg, 1.5 mmol) in dichloromethane (10 mL) was added followed by diisopropylethylamine (0.33 ml, 2.0 mmol) and the mixture was stirred for 2 hours at room temperature. The mixture was washed with water (10 ml), aqueous sodium bicarbonate (10 ml), water (2×10 ml), brine (10 ml), dried over magnesium sulfate and concentrated in vacuo. The crude product was chromatographed on silica (40 g) with ethyl acetate/heptane 4:1 to give 760 mg of (2S)-2-([N-methyl-N-{(1R)-1-(N-methyl-N-[(1R)-1-(methylcarbamoyl)-2-phenylethyl]carbamoyl)-2-(2-naphthyl)ethyl}carbamoyl]methoxymethyl)pyrrolidine-1-carboxylic acid tert-butylester. The obtained product was taken up in 50% trifluoroacetic acid in methylene chloride (5 ml) and stirred for 10 min. Then saturated sodium bicarbonate was added until pH 8 and the phases were separated. The aqueous phase was extracted with dichloromethane (2×10 ml) and the combined organic phases were washed with brine (5 ml), dried over magnesium sulfate and concentrated in vacuo. The product was redissolved in water (30 ml) and acetic s acid (2 ml) was added and the mixture was liophilized to give 720 mg of the acetate salt of the title compound as an amorphous powder.

Provenance & Evidence