C(=O)([O-])O.[Na+].Cl.[NH2:7][CH:8]([C:13](=[O:16])[CH2:14][CH3:15])[C:9]([O:11][CH3:12])=[O:10].O.[C:18](Cl)(=[O:27])[CH:19]=[CH:20][C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1>C(OCC)(=O)C>[C:18]([NH:7][CH:8]([C:13](=[O:16])[CH2:14][CH3:15])[C:9]([O:11][CH3:12])=[O:10])(=[O:27])[CH:19]=[CH:20][C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1Sodium hydrogen carbonate (10.0 g) was added to a mixture of methyl 2-amino-3-oxovalerate hydrochloride (9.1 g), ethyl acetate (50 ml) and water (40 ml) with ice-cooling and stirring followed by dropwise addition of a solution of cinnamoyl chloride (8.3 g) in ethyl acetate (10 ml). The whole mixture was stirred under ice-cooling for 2 hours and the ethyl acetate layer was separated. The aqueous layer was extracted with ethyl acetate. The ethyl acetate layers were combined, washed with water and dried over anhydrous magnesium sulfate. The solvent was then distilled off and isopropyl ether was added to the residue to give methyl 2-cinnamoylamino-3-oxovalerate as crystals; yield 8.8 g (63.8%). Recrystallization from ethanol gave colorless needles melting at 119°-120° C.
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