acetic acid to give ureido- or thioureidooxindoles, spiro-oxindoles and dihydroimidazoquinolones. However, if the starting compounds are substituted with a benzyl group at position 3, a C-debenzylation proceeds to give imidazoquinolones. According to a proposed reaction mechanism, a molecular rearrangement of the primarily formed mono-substituted urea or thiourea takes place. All compounds were characterized