[C:1]([O:8][CH3:9])(=[O:7])[CH2:2][CH2:3][C:4]([O-])=[O:5].C1N=CN(C(N2C=NC=C2)=O)C=1.O/[N:23]=[C:24](\[NH2:32])/[CH2:25][C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1>CN(C=O)C>[CH2:25]([C:24]1[N:32]=[C:4]([CH2:3][CH2:2][C:1]([O:8][CH3:9])=[O:7])[O:5][N:23]=1)[C:26]1[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=1Butanedioic acid, monomethyl ester (4.0 g, 30.3 mmole) and CDI (5.40 g, 33.3 mmole) were dissolved in anhydrous DMF (15 ml). After stirring the solution at room temperature for 3 hours, (1Z)-N′-hydroxy-2-phenylethanimidamide (5.0 g, 33.3 mmole) was added and the solution heated at 90° C. for 20 hours. After evaporation of solvent, the residue was dissovled in EtOAc. The organic phase was washed with water and brine, dried over Na2SO4. After filtration and evaporation of solvent, the residue was purified by flash chromatography on silica gel eluted with EtOAc/Hexane (25/75). The purification gave 5.2 g (69.7%) of product as light yellowish oil. LCMS calculated for C13H11N2O3(M+H): 247.1; found 247.0.
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