Hydrogen abstraction by chlorine atom from amino acids

Remarkable influence of polar effects on regioselectivity

Robert J. Oreilly, Bun Chan, Mark S. Taylor, Sandra Ivanic, George B. Bacskay, Christopher J. Easton, Leo Radom

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Quantum chemistry computations have been used to investigate hydrogen-atom abstraction by chlorine atom from protonated and N-acetylated amino acids. The results are consistent with the decreased reactivity at the backbone α-carbon and adjacent side-chain positions that is observed experimentally. The individual effects of NH 3 +, COOH, and NHAc substituents have been examined and reveal important insights. The NH 3 + group in isolation is found to be deactivating at the α-position, while the acetamido group is activating. For the COOH group, polar effects lead to a contrathermodynamic deactivation of the thermodynamically most favorable α-abstraction. In the N-acetylamino acid, the α-position is deactivated by the combined inductive effect of the substituents and the presence of an early transition structure, again overriding the greater thermodynamic stability of the α-centered radical product. Deactivation of the α-, β-, and γ-positions results in a peculiar stability for amino acids and peptides and their derivatives with respect to radical degradation.

Original languageEnglish
Pages (from-to)16553-16559
Number of pages7
JournalJournal of the American Chemical Society
Volume133
Issue number41
DOIs
Publication statusPublished - Oct 19 2011
Externally publishedYes

Fingerprint

Regioselectivity
Chlorine
Amino acids
Hydrogen
Amino Acids
Quantum chemistry
Atoms
Thermodynamics
Peptides
Thermodynamic stability
Carbon
Derivatives
Degradation
Acids

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Oreilly, R. J., Chan, B., Taylor, M. S., Ivanic, S., Bacskay, G. B., Easton, C. J., & Radom, L. (2011). Hydrogen abstraction by chlorine atom from amino acids: Remarkable influence of polar effects on regioselectivity. Journal of the American Chemical Society, 133(41), 16553-16559. https://doi.org/10.1021/ja205962b

Hydrogen abstraction by chlorine atom from amino acids : Remarkable influence of polar effects on regioselectivity. / Oreilly, Robert J.; Chan, Bun; Taylor, Mark S.; Ivanic, Sandra; Bacskay, George B.; Easton, Christopher J.; Radom, Leo.

In: Journal of the American Chemical Society, Vol. 133, No. 41, 19.10.2011, p. 16553-16559.

Research output: Contribution to journalArticle

Oreilly, RJ, Chan, B, Taylor, MS, Ivanic, S, Bacskay, GB, Easton, CJ & Radom, L 2011, 'Hydrogen abstraction by chlorine atom from amino acids: Remarkable influence of polar effects on regioselectivity', Journal of the American Chemical Society, vol. 133, no. 41, pp. 16553-16559. https://doi.org/10.1021/ja205962b
Oreilly, Robert J. ; Chan, Bun ; Taylor, Mark S. ; Ivanic, Sandra ; Bacskay, George B. ; Easton, Christopher J. ; Radom, Leo. / Hydrogen abstraction by chlorine atom from amino acids : Remarkable influence of polar effects on regioselectivity. In: Journal of the American Chemical Society. 2011 ; Vol. 133, No. 41. pp. 16553-16559.
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