PURPOSE: To obtain a fumaric monoester or a mesaconic monoester in high yield by isomerizing a maleic monoester or a citraconic monoester in the presence of a bromide and/or an iodide catalyst, a radical generating agent and water.
CONSTITUTION: A maleic monoester or a citraconic monoester is isomerized in the presence of a bromide and/or an iodide (e.g. ammonium bromide or ammonium iodide) as a catalyst, a radical generating agent (e.g. ammonium persulfate) and water to produce a fumaric monoester or a mesaconic monoester. By this method, coloring will not occur during the reaction, purification is easy, the reaction is rapidly advanced and high yield is achieved. The reaction is not affected by an atmosphere such as air and reaction temperature is readily controlled.
ISHIBASHI KOJI
KOINUMA YASUYOSHI
KATO KENJI
