Molecular rearrangement of 1-substituted 9b-hydroxy-3,3a,5,9b-tetrahydro-1H-imidazo[4,5-c]quinoline-2,4-diones—an unexpected pathway to new indole and imidazolinone derivatives

1-Substituted 3a-alkyl/aryl-9b-hydroxy-3,3a,5,9b-tetrahydro-1H-imidazo[4,5-c]quinoline-2,4-diones and 3′-substituted 3-alkyl/aryl-3-ureido-1H,3H-quinoline-2,4-diones react in boiling acetic acid to give 2-alkyl/aryl-1H-indol-3-yl-ureas and/or 1,3-bis[2-(2-oxo-2,3-dihydro-1H-imidazol-4-yl)-phenyl]-ureas. By the action of hydrochloric acid, the first of them rearrange to give 4-(2-aminophenyl)-1,3-dihydroimidazol-2-ones. The structure of 1,3-bis[2-(2-oxo-2,3-dihydro-1H-imidazol-4-yl)-phenyl]-ureas was confirmed by their synthesis. All compounds were characteried by their 1H NMR, 13C NMR, IR spectra, atmospheric pressure chemical ioniation mass spectra, and some of them also by 15N NMR spectroscopic data.