| 摘要 |
<p>PROBLEM TO BE SOLVED: To readily obtain maleimides used as an intermediate raw material for medicines and agricultural chemicals and useful as a raw material for various kinds of polymer compounds and a curing agent for rubbers by a simple operation. SOLUTION: An N-Carbnamoylmaleimide of formula I (R<1> and R<2> are each H, a halogen, a 1-10C alkyl or an aryl or R<1> and R<2> together form a cyclic substituent group by C-C bond) is subjected to decarbamoylation in the presence of a tertiary amine (e.g. triethylamine) in a solvent (e.g. ethyl acetate) at 60-150 deg.C to provide the objective maleimides of formula II. The resultant maleimide is separated from cyanuric acid obtained as a by-product by filtration and washed with water and the solvent is distilled away therefrom to provide the objective high-purity maleimide. In the method, decarbamoyl reaction is advanced even if a solvent except DMF difficult to isolate is used to isolate high-purity maleimide. The tertiary amine is used in an amount of 0.1-30wt.% based on the compound of formula I.</p> |
