Oxidation of Polynuclear Aromatic Hydrocarbons with Ceric Ammonium Sulfate: Preparation of Quinones and Lactones

Article abstract of DOI:10.1021/jo00240a013

The oxidation of polynuclear aromatic hydrocarbons with ceric ammonium sulfate (CAS) in sulfuric acid was investigated.Oxidation of benzofluoranthene (1) gave a mixture of the 7,12- and 2,3-diones 3 and 4.The 2,3-dione (4) was used as the starting material for a facile synthesis of 2,3-dihydro-2,3-dihydroxybenzofluoranthene (5) and the corresponding diol epoxide 6, which are potentially important metabolites of benzofluoranthene.In a similar manner, 2,3-dihydro-2,3-dihydroxyfluoranthene (7) and its diol epoxide 8 were prepared from fluoranthene.Oxidation of benzofluoranthene (2) with CAS did not yield quinones, but instead gave benzofluoreno<2,1-b>pyran-5,13-dione (9), which was identified by its spectral properties and by reduction with LiAlH4.The lactone 9 formed via initial K-region oxidation of 2.It was not formed from 1-hydroxybenzofluoranthene (12), which gave benzofluoranthene-1,2-dione (13) upon CAS oxidation.CAS oxidation of benzopyrene (14) gave a mixture of the 1,6- and 3,6-quinones 17 and 18.Treatment of benzanthracene (15) with CAS yielded 7-oxo-12-hydroxy-7,12-dihydrobenzanthracene (19) and the 7,12-quinone 20.Oxidation of chrysene (16) with CAS gave 6H-benzonaphtho<1,2-b>pyran-6-one (21) and the 5,6-quinone 22.The results of this study demonstrate that CAS oxidation is useful for the synthesis of certain PAH quinones or lactones, from polynuclear aromatic hydrocarbons, depending on the ring system.