[CH3:1][C:2]([C:4]1[CH:9]=[CH:8][C:7]([Cl:10])=[C:6]([Cl:11])[CH:5]=1)=[O:3].C(O)(=O)C.O.[C:17]([OH:21])(=[O:20])[CH:18]=[O:19]>O>[Cl:11][C:6]1[CH:5]=[C:4]([C:2](=[O:3])[CH2:1][CH:18]([OH:19])[C:17]([OH:21])=[O:20])[CH:9]=[CH:8][C:7]=1[Cl:10]A mixture of 3,4-dichloroacetophenone (3.84 g, 20.3 mmol), glacial acetic acid (20.0 ml), and glyoxylic acid hydrate (1.85 g, 20.1 mmol) was stirred at 90° C. for 23 hours. More glyoxylic acid hydrate (0.93 g) was added, and heating was continued for 41 hours. Water (200 ml) was added, and the mixture was extracted twice with ethyl acetate. The combined extracts were washed with brine, dried (MgSO4), and concentrated under reduced pressure. Recrystallization of the residue from ethyl acetate/heptane yielded 2.01 g (38%) of 4-(3,4-dichlorophenyl)-4-oxo-2-hydroxybutyric acid. This acid was used to prepare the title amide using General Procedure (D).
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