[Cl:1][C:2]1[C:3]([CH:24](OCC)[O:25]CC)=[N:4][C:5]([C:17]2[CH:22]=[CH:21][C:20]([Cl:23])=[CH:19][CH:18]=2)=[C:6]([F:16])[C:7]=1[N:8]=C1C=CC(=O)C=C1.S(=O)(=O)(O)O.C(Cl)Cl>C(#N)C.O>[NH2:8][C:7]1[C:6]([F:16])=[C:5]([C:17]2[CH:18]=[CH:19][C:20]([Cl:23])=[CH:21][CH:22]=2)[N:4]=[C:3]([CH:24]=[O:25])[C:2]=1[Cl:1]In a typical reaction, 4-((3-chloro-6-(4-chlorophenyl)-2-(diethoxymethyl)-5-fluoropyridin-4-yl)imino)cyclohexa-2,5-dienone is treated with a 1 M (molar) solution of sulfuric acid in a mixture of acetonitrile/water. The mixture is heated at reflux until the reaction is complete. The mixture is added to methylene chloride, and the organic layer is separated, washed with brine and dried. The solvent is evaporated to provide crude 4-amino-3-chloro-6-(4-chlorophenyl)-5-fluoropicolinaldehyde.
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