Piperazin-2-one → Cebaracetam
Reaktionsgleichung
[NH:1]1[CH2:6][CH2:5][NH:4][CH2:3][C:2]1=[O:7].ClC1C([O:15][C:16](=O)[CH2:17][N:18]2[CH2:22][CH:21]([C:23]3[CH:28]=[CH:27][C:26]([Cl:29])=[CH:25][CH:24]=3)[CH2:20][C:19]2=[O:30])=C(Cl)C(Cl)=C(Cl)C=1Cl>CN(C)C=O>[Cl:29][C:26]1[CH:25]=[CH:24][C:23]([CH:21]2[CH2:22][N:18]([CH2:17][C:16]([N:4]3[CH2:5][CH2:6][NH:1][C:2](=[O:7])[CH2:3]3)=[O:15])[C:19](=[O:30])[CH2:20]2)=[CH:28][CH:27]=1Komponenten
4
Edukt 2
Produkt 1
Reagenzien, Katalysatoren, Lösungsmittel 1
Versuchsvorschrift
4.46 g (44.6 mmol) of piperazin-2-one (ketopiperazine) and 300 ml of dimethylformamide are added to 22.4 g (44.6 mmol) of 2-[4-(p-chlorophenyl)-2-oxopyrrolidin-1-yl]-acetic acid pentachlorophenyl ester and the whole is stirred for 5 hours at room temperature. The whole is concentrated to dryness by evaporation under reduced pressure at 70°, stirred with 150 ml of ethyl acetate for 1 hour and then 150 ml of diethyl ether are added; the whole is filtered with suction, washed with 50 ml of diethyl ether and allowed to dry. 1-[4-(p-chlorophenyl)-2-oxopyrrolidin-1-ylacetyl]-3-oxopiperazine having a melting point of 205°-207° is obtained and can be purified further by recrystallisation from 300 ml of butanol, washing with 50 ml of diethyl ether and drying, and then melts at 208°-210°.