Phosgene → N-(5-chloropyrid-2-yl)-3-(4-chlorophenyl)-4-carbomethoxy-4-methyl-4,5-dihydro-1H-pyrazole-1-carboxamide

Participants

Reaction Steps

To 10 ml of acetonitrile containing 4.5 ml of 2.5M phosgene in ethyl acetate was added a slurry of 2.9 g (10 mmole) of 3-(4-chlorophenyl)-4-carbomethoxy-4-methyl-4,5-dihydro-1H-pyrazole hydrochloride 2.0 g (20 mmole) of triethylamine and 20 ml of acetonitrile. After stirring for 10 minutes the carbamoyl chloride was judged to have been formed and then 1.5 g (11 mmole) of 2-amino-5-chloropyridine was added with an additional 2 g of triethylamine. After stirring for 18 hours the mixture was partitioned between ether and water, washed with brine, dried over magnesium sulfate, filtered concentrated, and chromatographed yielding N-(5-chloropyrid-2-yl)-3-(4-chlorophenyl)-4-carbomethoxy-4-methyl-4,5-dihydro-1H-pyrazole-1-carboxamide, mp 130°-146° C. NMR data was consistent with the structure.

Provenance & Evidence