[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]([N+:8]([O-])=O)[C:3]=1/[C:11](=[C:16](\O)/[CH3:17])/[C:12]([O:14][CH3:15])=[O:13]>C(O)(=O)C.O.C(Cl)Cl.CO>[Cl:1][C:2]1[CH:7]=[CH:6][CH:5]=[C:4]2[C:3]=1[C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:16]([CH3:17])[NH:8]2(E)-Methyl 2-(2-chloro-6-nitrophenyl)-3-hydroxybut-2-enoate (14.76 mmol, 1.0 equiv.) was dissolved in acetic acid (96 ml), and a solution of TiCl3 (20%-w/w in 2 N HCl, 71.6 ml) was added, with stirring. The mixture was then heated for 5-10 min at 90° C. The reaction mixture was cooled with an ice bath and diluted with water and DCM/methanol (9:1, 100 ml). The phases were separated and the organic phase was washed with water and sat. NaCl solution. Drying over Na2SO4 was then carried out, followed by concentration under reduced pressure. The product was crystallized from hexane. Yield: 91%
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