反应详情

0.65 ml (0.72 g, 0.00443 moles) of ethyl pyrocarbonate are added to a solution of 1.0 g (0.00285 moles) of 1-(1',3'-bis/2",6"-dimethylphenyl/-4'-methyl-imidazolidine-2'-ylidene)-urea, prepared as described in Example 72, in 10 ml of dry chloroform, and the mixture is allowed to stand at room temperature for 48 hours. Thereafter the solvent and the excess of the reactant are distilled off under reduced pressure. The oily residue is dissolved in 10 ml of diethyl ether, the insolubles are filtered off, and the filtrate is concentrated to a final volume of about 2 ml. Next day the separated crystalline product is filtered off, washed with a small amount of diethyl ether and dried. 0.5 g (41.7%) of 1-(1',3'-bis/2",6"-dimethylphenyl/-4'-methyl-imidazolidine-2'-ylidene)-3-carbethoxy-urea are obtained; m.p.: 123°-125° C.

1. customprepared
2. distillationThereafter the solvent and the excess of the reactant are distilled off under reduced pressure
3. dissolutionThe oily residue is dissolved in 10 ml of diethyl ether
4. filtrationthe insolubles are filtered off
5. concentrationthe filtrate is concentrated to a final volume of about 2 ml
6. filtrationNext day the separated crystalline product is filtered off
7. washwashed with a small amount of diethyl ether
8. customdried