Stability of cyclic imine toxins: interconversion of pinnatoxin amino ketone and pinnatoxin A in aqueous media

J Org Chem. 2012 Nov 16;77(22):10435-40. doi: 10.1021/jo301632d. Epub 2012 Nov 6.


Pinnatoxins belong to the cyclic imine (CI) group of marine toxins with a unique toxicological profile. The need for structural integrity of the aliphatic 7-membered cyclic imine for the potent bioactivity of pinnatoxins has been experimentally demonstrated. In this study, we probe interconversion of the natural cyclic imine and its open form, pinnatoxin A amino ketone (PnTX AK), under physiologically relevant aqueous conditions. Our studies demonstrate the high stability of PnTX A. The unusual stability of the imine ring in PnTX A has implications for its oral toxicity and detoxification. These studies, as well the access to PnTX amino ketone, were enabled by the total synthesis of (+)-pinnatoxin A completed previously in our laboratory.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Alkaloids / chemical synthesis*
  • Alkaloids / chemistry*
  • Alkaloids / toxicity
  • Imines / chemistry*
  • Ketones / chemistry*
  • Marine Toxins / chemistry*
  • Molecular Structure
  • Spiro Compounds / chemical synthesis*
  • Spiro Compounds / chemistry*
  • Spiro Compounds / toxicity


  • Alkaloids
  • Imines
  • Ketones
  • Marine Toxins
  • Spiro Compounds
  • pinnatoxin A