Reaction of Azomethine<i>N</i>-Oxides. III. Reactions of Some Azomethine<i>N</i>-Oxides with Fluoranil, Phenyl Vinyl Sulfone, and β-Nitrostyrene
作者:Ahmed Moukhtar Nour El-Din
DOI:10.1246/bcsj.59.1239
日期:1986.4
Isomerization of 3H-indole 1-oxides in the presence of tetrafluoro-2,5-cyclohexadiene-1,4-dione (fluoranil) to the thermodynamically more stable lactams was found to proceed via formation of charge-transfer complexes. However, addition of fluoranil to some open chain nitrones did not give the corresponding amides. Both electron-deficient β-nitrostyrene and phenyl vinylsulfone did not form charge-transfer
The spin adducts formed under UVA irradiation or in the presence of mild oxidants in the reaction of a number of heteroaromatic bases and two indolic nitrones have been characterized by means of ESR spectroscopy. The formation of the spin adducts is explained via the Forrester–Hepburn mechanism, while the occurrence of inverted spin trapping is excluded. Photolysis of nitrones 1 and 2 or of the corresponding cyclic hydroxamic acids resulted in the formation of the related acyl nitroxides.