Trichloroacetyl isocyanate → [4-(3,5-Dichlorobenzyl)-3,5-diethyl-1h-pyrazol-1-yl]methyl carbamate

Participants

Reaction Conditions

Reaction Steps

A solution of the alcohol of Example 41 (280 mg, 0.90 mmol) in dichloromethane (5 ml) was cooled to 0° C., treated with trichloroacetyl isocyanate (128 μl, 1.1 mmol) and stirred at 0° C. for 30 minutes. The solution was soaked into a pad of alumina (neutral, activity II, Brockmann), washed with dichloromethane and then extracted with ethyl acetate. The organic extract was concentrated under reduced pressure. The crude material was purified by flash chromatography on silica gel eluting with a solvent gradient of cyclohexane:ethyl acetate (2:1, by volume) gradually changing to cyclohexane:ethyl acetate (1:1, by volume) to afford the title compound (238 mg) as a solid, m.p. 153–155° C.

Provenance & Evidence