反应详情

A mixture of cis-1,3-dibenzyl-2-oxoimidazolidine-4,5-dicarboxylic acid (35.4 g), benzene (500 ml), 9.5% ethanol (45 ml) and conc. sulfuric acid (5.0 g) was refluxed for 10 hours, cooled, washed successively with water, 5% aqueous sodium hydroxide and water, and then concentrated under reduced pressure. The residue was recrystallized from 95% ethanol to give diethyl cis-1,3-dibenzyl-2-oxoimidazolidine-4,5-dicarboxylate (32.1 g). M.P., 74°-76° C.

1. temperaturewas refluxed for 10 hours
2. temperaturecooled
3. washwashed successively with water, 5% aqueous sodium hydroxide and water
4. concentrationconcentrated under reduced pressure
5. customThe residue was recrystallized from 95% ethanol