Pyridine → [5-(1-methyl-cyclopropyl)-2-p-tolyl-2H-pyrazol-3-yl]-carbamic acid 2,2,2-trichloroethyl ester

Participants

Reaction Conditions

Reaction Steps

Treat a cooled (0° C.) solution of the 5-(1-methyl-cyclopropyl)-2-p-tolyl-2H-pyrazol-3-ylamine (5.68 g, 25 mmol) and pyridine (2.2 mL, 27.5 mmol) in THF (3 mL/mmol) with 2,2,2-trichloroethyl chloroformate (3.7 mL, 27.5 mmol). Maintain the reaction temperature at 0° C., and after 2 hours, add small portions of chloroformate (0.3 mL) and pyridine (0.2 mL). One hour later, dilute the reaction with water (150 mL) and extract with EtOAc (3×100 mL). Wash the combined organic phases with water (100 mL), saturated aq. NaHCO3 (50 mL), and saturated aq. sodium chloride (50 mL). Recrystallize the crude syrup from ethyl acetate/hexanes to provide the title compound as a white solid (8.18 g, 20.3 mmol; 81%). LCMS (ES+): m/z=402.2/404.2 [M+H].

Provenance & Evidence