[Na].[F:2][C:3]1[CH:12]=[CH:11][CH:10]=[C:9]([F:13])[C:4]=1[CH2:5][N:6]=[N+:7]=[N-:8].[C:14]([O:20]CC)(=[O:19])[CH2:15][C:16]([CH3:18])=O.[OH-].[Na+].Cl>O>[F:2][C:3]1[CH:12]=[CH:11][CH:10]=[C:9]([F:13])[C:4]=1[CH2:5][N:6]1[C:16]([CH3:18])=[C:15]([C:14]([OH:20])=[O:19])[N:8]=[N:7]1The starting material is prepared as follows: 2.53 g (0.11 mole) of sodium are dissolved in 60 ml of alcohol, then a mixture of 16.9 g (0.1 mole) of 2,6-difluorobenzyl azide and 14,3 g (0.11 mole) of ethyl acetoacetat in 60 ml of alcohol is added and the batch is heated for 16 hours to reflux. After addition of 120 ml of normal sodium hydroxide solution, the reaction mixture is refluxed for another 2 hours, then diluted with 200 ml of water and acidified to pH 1 with hydrochloric acid while cooling. The precipitated product is filtered with suction, washed first with water and then with ether and dried, affording 1-(2,6-difluorobenzyl)-5-methyl-1H-1,2,3-triazole-4-carboxylic acid with a melting point of 166°-167° C.
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