Triethylamine → (3R)-3-{(1R)-1-[(1R)-1-(3-methyl-[1,2,4]oxadiazol-5-yl)-2-phenylethylcarbamoyl]-2-(2-naphthyl)ethylcarbamoyl}piperidine-1-carboxylic acid tertbutyl ester

Participants

Reaction Steps

N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (0.42 g, 2.18 mmol) and 1-hydroxybenzotriazole monohydrate (0.33 g, 2.18 mmol) were added to a solution of (R)-N-tertbutoxycarbonyl-3-piperidine carboxylic acid (0.50 g, 2.18 mmol) in N,N-dimethylformamide (7 ml). After 30 min at 20° C. a mixture of (2R)-2-amino-N-[(1R)-1-(3-methyl-[1,2,4]oxadiazol-5-yl)-2-phenylethyl]-3-(2-naphthyl)propionamide hydrochloride (0.68 g, 1.56 mmol) and triethylamine (0.16 g, 1.56 mmol) in N,N-dimethylformamide (8 ml) was added. After 18 h at 20° C. the reaction mixture was poured on ice water (90 ml) and extracted several times with ethyl acetate (total 90 ml). The organic phases were collected and washed with aqueous citric acid (10%, 15 ml), a saturated solution of sodium hydrogencarbonate (3×15 ml) and water (3×15 ml). After drying (magnesium sulfate) the solution was concentrated in vacuo and purified by flash chromatography on silica gel (90 g) using ethyl acetate and heptane (3:2) as eluent to give 0.83 g of (3R)-3-{(1R)-1-[(1R)-1-(3-methyl-[1,2,4]oxadiazol-5-yl)-2-phenylethylcarbamoyl]-2-(2-naphthyl)ethylcarbamoyl}piperidine-1-carboxylic acid tertbutyl ester.

Provenance & Evidence