Water → 2,2,2-Trichloroethyl 3-tert-butyl-1-P-tolyl-1H-pyrazol-5-ylcarbamate

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Reaction Conditions

Reaction Steps

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+).

Provenance & Evidence