Derivatives of 4-aza-9-fluorenone

Derivatives of 1,3-indandione containing in position 2 a carbon chain with a δ-carbonyl group cyclize on heating with ammonium acetate in glacial acetic acid to form derivatives of 1,4-dihydro-4-aza-9-fluorenone. The latter are readily oxidized to the corresponding 4-aza-9-fluorenones. The IR and UV spectra of the compounds obtained are discussed.