Pulse Radiolytic Kinetic Study of the Decay of α-Methyl-Substituted Benzoquinone Radical Anions: A Possible Mechanistic Model for Bioreductive Alkylation Article

O’shea, KE, Fox, MA. (1991). Pulse Radiolytic Kinetic Study of the Decay of α-Methyl-Substituted Benzoquinone Radical Anions: A Possible Mechanistic Model for Bioreductive Alkylation . JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 113(2), 611-615. 10.1021/ja00002a032

cited authors

  • O’shea, KE; Fox, MA

authors

abstract

  • Pulse radiolysis and transient absorption spectroscopy were used to kinetically characterize the decay of several α-methyl-substituted 1,4-benzoquinone radical anions. Electron attachment rates, absorption spectra, extinction coefficients, and pKa’s for the reduced quinones are very similar regardless of substituent, but the decay kinetics are dependent on both substituent and pH. The semiquinone radical anions disproportionate at pH 7 regardless of substituent. At pH 3, the radical anion is readily protonated, and in the phenoxy- and methoxy-substituted models reductive elimination becomes competitive with disproportionation. The involvement of an intramolecular H-bonded intermediate is proposed in the formation of the quinone methide. The existence of such an intermediate is supported by theoretical results (AMI calculations). © 1991, American Chemical Society. All rights reserved.

publication date

  • January 1, 1991

Digital Object Identifier (DOI)

start page

  • 611

end page

  • 615

volume

  • 113

issue

  • 2