Synthesis of N-hydroxymaleimide and N-hydroxyitaconimide and their related derivatives

Abstract

Thermolysis of alkyl and aryl carbonates of N-hydroxy-3,6-epoxy-1,2,3,6-tetrahydrophthalimide yielded the corresponding alkyl or aryl N-maleimidyl carbonates. The benzyl or phenyl carbonate afforded N-hydroxymaleimide, either by treatment with trifluoroacetic acid or by refluxing in methanol. N-Hydroxyitaconimide was obtained by dehydration of N-hydroxyitaconamic acid with dicyclohexylcarbodi-imide (DCC). The DCC dehydration of N-acetoxy- and N-benzyloxy-itaconamic acids produced iminofuranones, which could be rearranged to imides. Deacylation of N-acetoxymaleimide was unsuccessful, whereas aminolysis of N-acetoxyitaconimide yielded the N-hydroxyimide.