An EPR study of the radicals from 5-nitrothiophenecarboxamides: a novel group of direct acting mutagens

The title compounds have been reduced to the corresponding radical anions by means of potassium tert-butoxide in dimethylsulphoxide solution, and their EPR spectra have been recorded. In the instance of meta-like isomers 1-7 the spectrum of initially formed radical anion is replaced by that of a second radical which after some time remains the only observable species. On the basis of the spectral parameters it is suggested that the secondary species are the radical anions of 3-carbamoyl-5-nitrothiophene-2-carboxylates substituted at the amidic function. © 1993.