Benzamide → Carbamic acid, ethyl ester

Participants

Reaction Steps

We have now discovered a method for the preparation of benzoylureas such as those disclosed in U.S. Pat. No. 3,748,356 and Belgian Pat. No. 833,288, which comprises the reaction of a benzamide, a C1 -C7 alkyllithium, a phenyl chloroformate and an amine. In one embodiment of the reaction, the benzamide is treated with the alkyllithium and a phenyl chloroformate in an inert solvent at a temperature of from about -80° to about -40° C. to form an intermediate urethane, the intermediate urethane is treated with an amine in an inert solvent at about -80° to about -40° C., and the temperature is slowly raised to from about 50° to about 100° C. to obtain the desired benzoylurea. In a second embodiment of the reaction, the benzamide is treated with the alkyllithium in an inert solvent at a temperature from about -80° to about -40° C. and the lithium salt so obtained is then treated with a carbamate at a temperature of about -80° to about -40° C., and the mixture is allowed to warm to from about 20° to about 40° C. to obtain the desired benzoylurea. The carbamate is obtained by the reaction of an amine with a phenyl chloroformate.

Provenance & Evidence