Chloroform → cis-(+-)-N-(2-(2,6-Dimethyl-1-piperidinyl)ethyl)-2-oxo-3-hydroxy-1-pyrrolidineacetamide

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Reaction Steps

1.50 g of (R/S)-2-(3-hydroxy-2-oxo-1-pyrrolidinyl)acetic acid are dissolved in 50 ml of chloroform and 10 ml of dimethylformamide. 1.08 g of N-hydroxysuccinimide are added thereto. Thereafter, 2.08 g of dicyclohexylcarbodiimide dissolved in 25 ml of chloroform are added. The mixture is stirred at room temperature for 4 hours and then the precipitated solid is filtered. The filtrate is concentrated to a volume of about 20 ml and then again filtered. The filtrate is evaporated and the residue is treated with 1.70 g of 94.7% cis-2-(2,6-dimethyl-1-piperidinyl)ethylamine. The mixture is left to stand at room temperature overnight and the excess cis-2-(2,6-dimethyl-1-piperidinyl)ethylamine is removed in vacuo. The residue is chromatographed on 60 g of aluminum oxide (activity grade I, basic). The fractions which are eluted with chloroform and alcohol are evaporated. The residue is stirred at room temperature in 35 ml of diethyl ether/ethyl acetate (2:1). There is obtained (R/S)-cis-N-[2-(2,6-dimethyl-1-piperidinyl)ethyl] -2-(3-hydroxy-2-oxo-1-pyrrolidinyl)acetamide (melting point 116°-120°) which melts at 126°-128° after repeated chromatography on aluminum oxide (activity grade III, neutral) and recrystallization from ethyl acetate.

Provenance & Evidence