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

Participants

Reaction Conditions

Reaction Steps

To an ice-salt cooled solution of 5-(1-methoxy-cyclopropyl)-2-p-tolyl-2H-pyrazol-3-ylamine (Preparation 11, 2.43 g, 10 mmol) and pyridine (0.9 mL, 11 mmol) in THF (30 mL), add a solution of 2,2,2-trichloroethylchloroformate (2.12 g, 10 mmol) in THF (10 mL) dropwise. Stir at −15° C. for 0.5 hour, then at 22° C. for 1 hour. Partition the reaction mixture between dichloromethane (50 mL) and saturated aq. sodium bicarbonate (50 mL). Isolate the aqueous phase and extract twice with dichloromethane (25 mL each). Dry the combined organic phases over sodium sulfate and concentrate. Subject residue to silica gel chromatography eluting with hexanes and ethyl acetate to give a white solid (3.73 g, 89% yield, ES+(m/z) 418.1 [M+H]).

Provenance & Evidence