[Na][Na].[C:3]([CH2:11][C:12]([C:14]1[CH:22]=[CH:21][CH:20]=[CH:19][C:15]=1[C:16]([OH:18])=[O:17])=O)(=O)[C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.Cl.O.[NH2:25][NH2:26]>CO.O>[C:16]([C:15]1[CH:19]=[CH:20][CH:21]=[CH:22][C:14]=1[C:12]1[CH:11]=[C:3]([C:4]2[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=2)[NH:26][N:25]=1)([OH:18])=[O:17]To a slurry of 100 g of the disodium salt of 2-benzoylacetylbenzoic acid in 400 ml of methanol is added first 12.5 g concentrated hydrochloric acid, followed by 11 g of hydrazine hydrate. This reaction mixture is heated at reflux for one-half hour, cooled to 5°-10°, acidified to pH 3 with concentrated hydrochloric acid, and diluted with 300 ml of water. The crystals are filtered off and recrystallized from ethanol-water, yielding 59 g of 3-(2-carboxyphenyl)-5-phenylpyrazole, mp 204°-205.5° .
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