Assignment of H-1 and C-13 spectra for polyprenol-12, a molecule with severe H-1 and C-13 spectral crowding, with the aid of high-resolution, C-13-detected, C-13-H-1 shift correlation spectra

Polyprenol-12 contains a linear sequence of 12 isoprene units. As a result, there is severe crowding in several regions of the H-1 and C-13 spectra. N evertheless, it is possible to assign a substantial majority of individual resonances as well as to confirm the number and sequence of E and Z isopren e units with the aid of high-resolution (0.001 ppm along each axis) C-13-de tected C-13-H-1 shift correlation spectra. By contrast, the corresponding H -1-detected sequences (e.g., HSQC and HMBC) do not have sufficient resoluti on to allow these assignments, in spite of their higher sensitivity.