Author's Organization：Showa College of Pharmaceutical Sciences Showa College of Pharmaceutical Sciences Showa College of Pharmaceutical Sciences Faculty of Pharmaceutical Sciences, Kanazawa University.
Eliminative ring expansion of 4-acetoxy (or mesyloxy)-2-azabicyclo [3.2.0] heptan-3-ones (7) yielded 1, 5-dihydro-2H-azepin-2-ones (dihydro-2-azatropones) which, on DDQ oxidation, afforded the 2H-azepin-2-ones (2-azatropones, 9). In contrast to azatropolones, the 2-azatropones were stable to protic solvents. However, irreversible solvolytic changes were observed in both acidic and basic media.
