Substituent effects on reductive cleavage of N-methylarenesulfonanilides. Cleavage by sodium anthracene and electrochemically at the vitreous carbon electrode

K. Saboda Quaal, Sungchul Ji, Young M. Kim, W. D. Closson, Jon A Zubieta

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The relative rates of cleavage of ten para-substituted N-methylbenzenesulfonanilides by sodium anthracene in tetrahydrofuran at 25°C were determined. The rates of those with less electronegative substituents (p-dimethylamino through p-fluoro) give a moderately good correlation with σ constants, ρ = 1.91 (r = 0.987). More strongly electron-withdrawing substituents, however, result in a cleavage rate much slower than expected due to reduction of the substituent rather than of the sulfonyl group. Electrochemical reduction in acetonitrile solution at a vitreous carbon electrode proceeds via an irreversible two-electron process. The peak potentials of all the sulfonamides give an excellent correlation with σn constants, ρ = 1.07 V (r = 0.995). Whether this is an eec or ece process is discussed, as well as possible causes for the large differences between homogeneous and electrochemical reduction. A suggested value of σn for the p-methanesulfinyl group is +0.54.

Original languageEnglish (US)
Pages (from-to)1311-1316
Number of pages6
JournalJournal of Organic Chemistry
Issue number7
StatePublished - 1978
Externally publishedYes


ASJC Scopus subject areas

  • Organic Chemistry

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