1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → ((S)-1-[2-(6-bromopyridin-2-yl)-2-oxoethylcarbamoyl]ethyl}carbamic acid tert-butyl ester

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Reaction Steps

To a suspension of 2-amino-1-(6-bromopyridin-2-yl)ethanone hydrochloride (500 mg, 1.99 mmol) obtained in Step 1 of example 6, (S)-N-tert-butylcarbonylalanine (376 mg, 1.99 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (379 mg, 1.99 mmol), 1-hydroxybenzotriazole monohydrate (305 mg, 1.99 mmol) in acetonitrile (11 ml), a solution of triethylamine (0.7 ml) in acetonitrile (4 ml) was added dropwise while ice-cooled for 15 minutes. After the mixture was stirred at the same temperature for 1 hour, water was added and extracted with ethyl acetate. After the organic layer was washed with water, a saturated brine, dried over magnesium sulfate, the residue obtained by vacuum concentration was purified by flash chromatography on silica gel (n-hexane:ethyl acetate=2:1) and the title compound (456 mg, 59%) was obtained.

Provenance & Evidence