1,3-Propanediamine, N'-(ethylcarbonimidoyl)-N,N-dimethyl-, monohydrochloride → N-(2-hydroxybutanoyl)glycine benzyl ester

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Reaction Steps

1.50 g (13.6 mmol) of lithium 2-hydroxybutanoate, 4.60 g (13.6 mmol) of glycine benzyl ester p-toluenesulfonic acid salt, and 1.84 g (1.36 mmol) of 1-hydroxybenzotriazole monohydrate (HOBt) were added to 80 mL of acetonitrile and stirred at room temperature for 20 minutes. The mixture was further mixed with 2.61 g (13.6 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and stirred at room temperature overnight. After the reaction mixture was filtered, the filtrate was vacuum-concentrated and the residue was dissolved in 200 mL of ethyl acetate. Washing with 1N hydrochloric acid and an aqueous solution saturated sodium hydrogen carbonate was carried out successively and drying over anhydrous sodium sulfate was carried out. After the solvent as removed by distillation, the residue was purified by flash column chromatography on silica gel (No. 9385, Merck) using a solvent mixture of hexane and ethyl acetate at 1:2 ratio to obtain N-(2-hydroxybutanoyl)glycine benzyl ester as a colorless oily substance (1.67 g, yield 49%).

Provenance & Evidence