[Cl:1][C:2]1[CH:11]=[CH:10][C:5]([C:6](Cl)=[N:7][OH:8])=[CH:4][CH:3]=1.[CH3:12][CH2:13][O:14][C:15](/[CH:17]=[C:18](/N1CCCC1)\[CH3:19])=[O:16].C(N(CC)CC)C>C(O)C>[CH2:13]([O:14][C:15]([C:17]1[C:6]([C:5]2[CH:10]=[CH:11][C:2]([Cl:1])=[CH:3][CH:4]=2)=[N:7][O:8][C:18]=1[CH3:19])=[O:16])[CH3:12]To a suspension of 4-chloro-N-hydroxy-benzimidoyl chloride (1.11 g, 5.88 mmol) in dry ethanol (9 ml) was added a solution of ethyl (E)-3-(1-pyrrolidino)crotonate (1.08 g, 5.88 mmol) and triethylamine (492 μl, 3.53 mmol) in dry ethanol (9 ml) over a period of twenty minutes at room temperature. The suspension was stirred for eighteen hours before the mixture was concentrated and the residue partitioned between ethyl acetate and water. The organic layer was washed with 0.5 N HCl and brine, before it was dried and concentrated in vacuo. The residue was purified by flash column chromatography with a gradient of ethyl acetate and hexanes on silica gel (40 g) to give the title compound as a white solid (1.09 g): 1H NMR (CDCl3, 200 MHz): δ=7.57 (m, 2H), 7.42 (m, 2H), 4.25 (q, J=7.0 Hz, 2H), 2.74 (s, 3H), 1.27 (t, J=7.0 Hz, 3H); MS: (+) m/z 266.31 (M+1).
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