Cl[CH:2]=[CH:3][C:4]1[C:5]([C:11]([F:14])([F:13])[F:12])=[N:6][N:7]([CH3:10])[C:8]=1[CH3:9].CC(C)([O-])C.[K+].[Cl-].[NH4+]>C1COCC1>[C:3]([C:4]1[C:5]([C:11]([F:13])([F:14])[F:12])=[N:6][N:7]([CH3:10])[C:8]=1[CH3:9])#[CH:2]1.27 g (5.67 mmol) of 4-(2-chloroethenyl)-1,5-dimethyl-3-(trifluoromethyl)-1H-pyrazole from Example 1 are dissolved in 40 ml of dry THF and placed under a protective gas atmosphere. After cooling the reaction solution to 0° C., 1.91 (17.0 mmol) of potassium tert-butoxide are introduced and, after the addition is complete, the mixture is stirred at 20° C. for 3 hours. After the end of the reaction, a saturated ammonium chloride solution (25 ml) is added and the mixture is extracted twice with 30 ml each time of methylene chloride. The combined organic phases are dried over magnesium sulphate, the solvent is removed by distillation and 4-ethynyl-1,5-dimethyl-3-(trifluoromethyl)-1H-pyrazole is isolated as a microcrystalline solid in a yield of 79% of theory.
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