Cl.[CH3:2][CH:3]([CH:5]1[NH:9][C:8](=[O:10])[CH2:7][NH:6]1)[CH3:4].N1C2(CCCCC2)NC[C:12]1=O.C(=O)([O-])[O-].[K+].[K+].[O:28]1[CH2:35][CH:29]1[CH2:30][C:31]([O:33]C)=[O:32]>CC(C)=O.O>[CH3:12][N:6]1[CH2:7][C:8](=[O:10])[NH:9][CH:5]1[CH:3]([CH3:4])[CH3:2].[OH:28][CH:29]([CH3:35])[CH2:30][C:31]([O-:33])=[O:32]
12 g 2-(1-methylethyl)-4-imidazolidinone hydrochloride ((5); R4 =H, R5 =isopropyl) (0.073 moles) are shaken with 20 ml water and treated with 5 g potassium carbonate (0.036 moles). 8.5 g methyl 3,4-epoxybutanoate (0.073 moles) and 12 ml acetone are added. The mixture is stirred for 45 h at 70° C. After evaporating, the residue is chromatographed on silica, eluting with 8:2 ethyl acetate/methanol. The main fractions are combined and evaporated. 2.5 g of methyl 2-(1-methylethyl)-4-oxoimidazolidine-β-hydroxybutanoate, m.p. 109°-122° C., are obtained as a white powder (14.4%). 2.0 g of this compound (0.0082 mole) are heated to boiling for 15 h with 8.8 ml DMF and 2.2 ml water. After evaporation in vacuo, the residue is taken up with methanol, and filtered. 0.74 g oxiracetam is obtained as a white crystalline powder, m.p. 167°-70° C. (57.4%).
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