Campus Units

Chemistry, Biochemistry, Biophysics and Molecular Biology

Document Type

Article

Publication Version

Published Version

Publication Date

8-20-1999

Journal or Book Title

Journal of the American Chemical Society

Volume

121

Issue

35

First Page

7979

Last Page

7988

DOI

10.1021/ja9906002

Abstract

A NMR study was conducted on the antiviral and antitumor agents hypericin and hypocrellin A and B, whose activity is light induced. Elucidation of the conformational/tautomeric properties of these polycyclic quinones is important for interpreting their photophysical behavior in the excited state. Evidence for interconversion between ground-state tautomers or other conformational isomers was sought in temperature-dependent 1H NMR and 2D-ROESY studies. For hypericin and hypocrellin B, only one ground-state species is observed. For hypocrellin A, however, three species are significantly populated in the ground state due to the high flexibility of its 7-membered ring. In the latter case dynamic NMR simulations were performed to obtain kinetic and thermodynamic parameters for the sequential interconversion occurring between the three species. The implications of these results for the interpretation of the light-induced primary processes in these systems are discussed.

Comments

Reprinted (adapted) with permission from Journal of the American Chemical Society 121 (1999): 7979, doi:10.1021/ja9906002. Copyright 1999 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

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