反应详情

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.

1. additionare added
2. filtrationthe precipitated solid is filtered
3. concentrationThe filtrate is concentrated to a volume of about 20 ml
4. filtrationagain filtered
5. customThe filtrate is evaporated
6. additionthe residue is treated with 1.70 g of 94.7% cis-2-(2,6-dimethyl-1-piperidinyl)ethylamine
7. waitThe mixture is left
8. waitto stand at room temperature overnight
9. customthe excess cis-2-(2,6-dimethyl-1-piperidinyl)ethylamine is removed in vacuo
10. customThe residue is chromatographed on 60 g of aluminum oxide (activity grade I, basic)
11. washThe fractions which are eluted with chloroform and alcohol
12. customare evaporated
13. stirringThe residue is stirred at room temperature in 35 ml of diethyl ether/ethyl acetate (2:1)