Phosgene → N-(4-trifluoromethylphenyl)-3-(4-chlorophenyl)-4-methyl-4-isocyano-4,5-dihydro-1H-pyrazole-1-carboxamide

Participants

Reaction Steps

To 4.5 g (10 mmole) of N-(4-trifluoromethylphenyl)-3-(4-chlorophenyl)-4-methyl-4-(N-formylamino)-4,5-dihydro-1H-pyrazole-1-carboxamide (Example 64) and 3.4 ml (23 mmole) of triethylamine in 25 ml of methylene chloride at reflux was slowly added 5.5 ml of a 2.0M solution of phosgene in methylene chloride. After refluxing for 30 minutes the mixture was twice washed with water, dried over anhydrous magnesium sulfate, filtered, concentrated in vacuo, and chromatographed on silica gel using diethyl ether and hexanes to yield 0.7 g of the title compound, a yellow solid, mp 171°-173° C.

Provenance & Evidence