Pyrrole photo-oxidation. The direct formation of maleimides

Abstract

Photo-oxidation of 3,4-diethylpyrrole in methanol gives mainly diethylmaleimide and 3,4-diethyl-5-methoxy-Δ³-pyrrolin-2-one; photolysis of pyrrole under similar conditions gives mainly 5-methoxy-Δ³-pyrrolin-2-one with a low yield of maleimide, but in aqueous solution, only 5-hydroxy-Δ³-pyrrolin-2-one and no maleimide is formed.