Dr DAVID S. RYCROFT

Structural elucidation of natural products using NMR spectroscopy

 [Glasgow University Crest]
A central aim has been to develop ways of organising and presenting the structural elucidation process so that the result is unprejudiced by known structures. Experimentally-determined through-bond and through-space connectivity is utilised to extend structural fragments into complete structures using arguments based as firmly as possible on logic rather than on intuition and prior knowledge of related compounds. This direct approach is particularly appropriate and powerful when novel compounds are encountered where even the structural type is completely unknown.
These ideas are applied in several areas of natural product chemistry, especially in collaboration with Prof. J.D. Connolly. Two examples are shown below: haemoventosin, a lichen pigment, and entilin A, a heptanortriterpenoid from a medicinal plant.

Lichens

The structure of haemoventosin, the red pigment of Ophioparma ventosa, was revised by us. Connectivity arguments were unable to resolve the crucial question of the ortho- or para- nature of the quinone, which was finally solved chemically by considering the structure of the reduction product of the monoacetyl derivative.

Medicinal plants

Many compounds with interesting and unusual structures have been isolated from plants used in native systems of medicine.
Entilin A from a Cameroonian sample of Entandrophragma utile (Meliaceae) is a novel heptanortriterpenoid derivative where long-range correlations in 2D C/H spectra were crucial in arriving at the heptacyclic structure.

Selected publications
D S Rycroft - Research Interests
Chemistry Staff