[NH:1]1[CH:5]=[CH:4][CH:3]=[N:2]1.[H-].[Na+].[H][H].[CH3:10][C:11]([CH3:25])([CH3:24])[C:12]([O:14][C:15]1[CH:20]=[CH:19][C:18]([CH2:21]Br)=[CH:17][C:16]=1[Cl:23])=[O:13]>CN(C)C=O>[CH3:10][C:11]([CH3:25])([CH3:24])[C:12]([O:14][C:15]1[CH:20]=[CH:19][C:18]([CH2:21][N:1]2[CH:5]=[CH:4][CH:3]=[N:2]2)=[CH:17][C:16]=1[Cl:23])=[O:13]
A mixture of 15.3 g of pyrazole, 89.9 g of sodium hydride (60% oil dispersion) and 200 ml of anhydrous N,N-dimethylformamide was stirred at 60° to 70° C. under a nitrogen atmosphere for 2 hours. After the evolution of hydrogen gas ceased, the mixture was cooled to 10° C. To this mixture was added dropwise an anhydrous N,N-dimethylformamide (300 ml) solution of 68 g of 4-bromomethyl-2-chlorophenyl 2,2-dimethylpropanoate at room temperature under stirring over 1 hour, and the mixture was stirred at 80° C. for 1 hour. After cooling, the mixture was poured into ice water, which was extracted with ethyl acetate. The organic layer was washed with saturated aqueous ammonium chloride solution and then saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue was subjected to silica gel column chromatography, which afforded 39.5 g of 2-chloro4-(1-pyrazolyl)methylphenyl 2,2-dimethylpropanoate as a colorless oil. Yield, 60%.
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