Oral Presentation Australian & New Zealand Society of Magnetic Resonance Conference 2017

Molecular modelling in conjunction with high field nmr secures the structure of an extensively rearranged cytotoxic norditerpene from the australian nudibranch goniobranchus splendidus (#38)

Louise C Forster 1 2 , Greg K Pierens 3 , Andrew M White 4 , Karen L Cheney 5 , Pradeep Dewapriya 4 , Robert J Capon 4 , Mary J Garson 2
  1. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
  2. School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
  3. Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia
  4. Institute for Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
  5. School of Biological Sciences, The University of Queensland, Brisbane, Queensland, Australia

An individual Goniobranchus splendidus specimen collected from Mackay, Australia, was found to contain an array of secondary metabolites sequestered from its sponge diet. A cytotoxic oxygenated norditerpene possessing an unprecedented carbon skeleton was characterized from the conspicuously patterned mollusk. The high field NMR analysis could not determine the relative stereochemistry of the compound. Therefore, chemical shifts for four candidate diastereomers of Epoxygoniolide-1 were calculated using molecular mechanics and density functional theory (DFT). The mean absolute error (MAE) from the Boltzmann averaged chemical shifts was still not conclusive and a statistical analysis of the chemical shifts using the DP4+ algorithm1 was undertaken. The DP4+ calculations indicated the 10S* 12R* stereoisomer had a 90.4% probability of being the correct structure.

 

  1. 1.Grimblat, N.; Zanardi, M. M.; Sarotti, A. M. J. Org. Chem. 2015, 80, 12526-12534. (http://sarotti-nmr.weebly.com/).