[H-].[Na+].C(=N[OH:11])C1C=CC=CC=1.[H][H].[Cl:14][C:15]1[C:25]([Cl:26])=[C:24]([C:27](=[O:37])[C:28]2[CH:33]=[CH:32][C:31]([N+]([O-])=O)=[CH:30][CH:29]=2)[CH:23]=[CH:22][C:16]=1[O:17][CH2:18][C:19]([OH:21])=[O:20]>CN(C=O)C>[Cl:14][C:15]1[C:25]([Cl:26])=[C:24]([C:27](=[O:37])[C:28]2[CH:33]=[CH:32][C:31]([OH:11])=[CH:30][CH:29]=2)[CH:23]=[CH:22][C:16]=1[O:17][CH2:18][C:19]([OH:21])=[O:20]In the above described equipment, 0.312 g. of sodium hydride in 17.5 ml. of DMF is stirred while dropwise adding 0.874 ml. of benzaldoxime. The exothermic reaction forms a heavy precipitate while generating hydrogen gas. When the H2 -evolution ceases, 1,4806 g. of 2,3-dichloro-4-(4-nitrobenzoyl)phenoxyacetic acid is added, which will start H2 -evolution again and produce a homogenous dark solution. Upon further stirring, a precipitate starts to form which after several hours may become heavy enough to interfere with the magnetic stirrer. After 15 hours, the mixture is diluted with 175 ml. of water and filtered. By acidifying the filtrate with concentrated HCl to a pH of 2, a milky oil separates which solidifies upon standing. After collecting the crystalline material by filtration, washing it with cold water and drying it at 60° C. under house vaccum, 1.1986 g. (88% of theory) of 2,3-dichloro-4-(4-hydroxybenzoyl)phenoxyacetic acid is obtained.
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