Ethyl chloroformate → Ethyl (4-chloro-2-fluorophenyl)carbamate

Participants

Reaction Steps

A solution of 6.9 grams (47 mmole) of 4-chloro-2-fluoroaniline in 75 mL of pyridine was stirred and cooled in an ice bath. During 15 minutes, 5.4 grams (50 mmole) of ethyl chloroformate was added dropwise. Upon completion of the addition the reaction mixture was heated at 60°-70° C. for 1.5 hours, then concentrated under reduced pressure to a residue. The residue was stirred with 150 mL of aqueous 3N hydrochloric acid, and the resulting precipitate was collected by filtration. The precipitate was washed with aqueous 3N hydrochloric acid and then with water. The precipitate was dried under ambient conditions for about 18 hours, then dried under vacuum for two hours, yielding 9.6 grams of ethyl N-(4-chloro-2-fluoro-phenyl)carbamate. The NMR spectrum was consistent with the proposed structure.

Provenance & Evidence