Exploring Ground-State Heterogeneity of Hypericin and Hypocrellin A and B: Dynamic and 2D ROESY NMR StudyJournal of the American Chemical Society
Publication VersionPublished Version
AbstractA 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.
Copyright OwnerAmerican Chemical Society
Citation InformationAlexandre V. Smirnov, D. Bruce Fulton, Amy H. Andreotti and Jacob W. Petrich. "Exploring Ground-State Heterogeneity of Hypericin and Hypocrellin A and B: Dynamic and 2D ROESY NMR Study" Journal of the American Chemical Society Vol. 121 Iss. 35 (1999) p. 7979 - 7988
Available at: http://works.bepress.com/amy_andreotti/16/