4-Chlorophenyl Isocyanate → 1H-Pyrazole-4-carboxylic acid, 3-(4-chlorophenyl)-1-(((4-chlorophenyl)amino)carbonyl)-4,5-dihydro-4-methyl-, methyl ester

Participants

Reaction Steps

An ether solution of 3-(4-chlorophenyl)-4-carbomethoxy-4-methyl-4,5-dihydro-1H-pyrazole (Example O) (approximately 1.8 mole) is treated with 286 g (1.86 mole) of 4-chlorophenyl isocyanate at a rate sufficient to maintain a mild reflux. After stirring for 30 minutes solvent is removed to 2/3 of the volume to afford a semisolid. After cooling in an ice bath solid product is filtered and washed with cold hexane and dried yielding 702 g (95%) of N,3-bis-(4-chlorophenyl)-4-carbomethoxy-4-methyl-4,5-dihydro-1H-pyrazole-1-carboxamide. NMR data was consistent with the structure.

Provenance & Evidence