Reactivity of bis(arylcarbamoyl)-N-arylphenacylamine oximes. Synthesis of 1,3-dihydroimidazol-2-ones and N-unsubstituted O-arylcarbamoylhydroxylamines

Abstract

N-Arylphenacylamine oximes I reacted with aryl isocyanates in refluxing benzene to give bis(arylcarbamoyl)-N-arylphenacylamine oximes 2 in good yields. Compounds 2 reacted with equimolar amount of TsOH.H2O in THF at room temperature to give imidazol-2-ones 5 and O-arylcarbamoylhydroxylammonium tosylates 6 in high yields. Compounds 2 were heated under vacuum to induce Beckmann fragmentation but the resulting products were 1,3,4-triaryl-1,3-dihydroimidazol-2-ones 5 instead of the expected 1,3-diazetidinones 4.