Conformational analysis of asperlin by NMR spectroscopy and molecular modeling

NOESY experiments and computerised molecular modeling have been employed to examine the configuration and conformation of the epoxypropyl side chain of asperlin in benzene solution. The data support the conclusion that the oxirane ring in this molecule has the 6S,7R configuration. Moreover, the JH-5.H-6 coupling constant about the C-5C-6 bond has been calculated using an equation suitable for the H-5C-5C-6H-6 segment. This value does not support a single conformation, but rather conformational averaging that provides good agreement between the theoretical and experimental parameters.