Researchers in China and Hungary have discovered a new marine natural product with an unprecedented carbon structure and unusual structural features. The compound, called Benthol A, was isolated from unicellular algae called dinoflagellates from the South China Sea.
Marine organic compounds with long polyol carbon chains and many stereocenters are known as super carbon chain compounds and comprise two main families: polyol-polyene compounds and lead frame polyethers. Because of their complexity, it is very difficult to determine their absolute configurations.
Using an extensive range of analytical techniques, Benthol A has been determined to have a C.72 Backbone with eight scattered Etherr rings. The researchers identified its planar structure and the absolute configuration of 35 carbon stereocenters.
Starting from high-resolution ESI-MS, the researchers first determined the molecular formula of the compound, followed by the carbon environments and carbon-carbon bond compounds using various NMR techniques and 13C enrichment. Once the connectivity of the structure was established, the researchers turned to identifying the stereochemistry of the entire molecule through chemical degradation. In the next step, the relative configurations and finally the absolute configuration were determined through stereo-specific measurements and theoretical calculations.
In contrast to previously identified super carbon chain compounds, Benthol A does not have separate hydrophilic and hydrophobic regions, and its bioactivity is very different. Principal component analysis places it into a new group of super carbon chains that the researchers call polyol-polyether compounds.