Cl.[NH2:2][C:3]1[N:7]([C:8]2[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][CH:9]=2)[N:6]=[C:5]([C:15]([CH3:18])([CH3:17])[CH3:16])[CH:4]=1.O.[OH-].[Na+].Cl[C:23]([O:25][CH2:26][C:27]([Cl:30])([Cl:29])[Cl:28])=[O:24]>CCOC(C)=O>[Cl:28][C:27]([Cl:30])([Cl:29])[CH2:26][O:25][C:23]([NH:2][C:3]1[N:7]([C:8]2[CH:13]=[CH:12][C:11]([CH3:14])=[CH:10][CH:9]=2)[N:6]=[C:5]([C:15]([CH3:18])([CH3:17])[CH3:16])[CH:4]=1)=[O:24]A mixture of 5-amino-3-t-butyl-1-p-tolylpyrazole hydrochloride (300 g, 1.13 mol), water (0.9 L), EtOAc (2.1 L) and NaOH (117 g, 2.84 mol) was stirred between 5-15° C. for 30 min. To this mixture, 2,2,2-trichloroethyl chloroformate (342 g, 1.58 mol) was added over 1 h between 5-15° C. The mixture was stirred at room temperature for 2 h, and then the aqueous layer was separated from the EtOAc layer. The EtOAc layer was washed with brine (2×0.9 L) and dried over MgSO4 (60 g). The EtOAc layer was collected by filtration. To this solution, heptane was added. A part of the solution was removed by distillation. The product was crystallized from the solution, collected by filtration and dried in vacuum oven to constant weight. Yield: 409 g, 90%. 1H NMR (CDCl3) δ 7.40 (d, 2H), 7.30 (d, 2H), 6.40 (s, 1H), 4.80 (s, 2H), 2.40 (s, 3H), 1.40 (s, 9H). MS (EI) m/z 404 (M+).
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