title: 2-Nitrofluoren-9-one: a unique mutagen formed in the photo-oxidation of 2-aminofluorene.
abstract: Exposure of solutions of 2-aminofluorene (2-AF, dissolved in dimethylsulfoxide) to near ultraviolet light (u.v.a. wavelengths of 320-400 nm) results in the formation of a variety of photo-products, several of which are direct-acting mutagens in the Ames/Salmonella standard-plate assay. Previously published results from our laboratory have described the chemical identification and kinetics of formation of two of these photo-induced mutagens, 2-nitrosofluorene and 2-nitrofluorene. In this report we present recent data concerning the isolation and chemical identification of another mutagenic photoproduct of u.v.a.-irradiated 2-AF, 2-nitrofluoren-9-one (2-NO2F-9-one). Data are also presented concerning the kinetics of phototransformation of 2-aminofluoren-9-one, an early-appearing and predominant photoproduct in u.v.a.-irradiated solutions of 2-AF, into 2-NO2F-9-one. It is well established that N-oxidation is a critical step in the biotransformations (i.e. enzymatic metabolism) of primary aromatic amines into proximate mutagens/carcinogens. In addition to u.v.a.-mediated N-oxidation of aromatic amines, selective ring photo-oxidation can also occur, resulting in, for example, the production of a carbonyl group at the 9-position of the fluorene molecule. The formation of mutagenic 2-NO2F-9-one in the photochemical oxidation of 2-AF appears to be unique to this process.
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005449:Fluorenes / Q000528:radiation effects*; D013058:Mass Spectrometry; D009152:Mutagenicity Tests; D009153:Mutagens; D010084:Oxidation-Reduction; D010777:Photochemistry; D014466:Ultraviolet Rays
chemical_list: D005449:Fluorenes; D009153:Mutagens; C047878:2-nitro-9-fluorenone; C012177:2-aminofluorene