Brevetoxin

Brevetoxin (PbTx), or brevetoxins, are a suite of cyclic polyether compounds produced naturally by a species of dinoflagellate known as Karenia brevis. Brevetoxins are neurotoxins that bind to voltage-gated sodium channels in nerve cells, leading to disruption of normal neurological processes and causing the illness clinically described as neurotoxic shellfish poisoning (NSP).

Although brevetoxins are most well-studied in K. brevis, they are also found in other species of Karenia and at least one large fish kill has been traced to brevetoxins in Chattonella.

Brevetoxin A Brevetoxin B
chemical structure
subtypes
  • Brevetoxin-1 (PbTx-1) R = -CH2C(=CH2)CHO
  • Brevetoxin-7 (PbTx-7) R = -CH2C(=CH2)CH2OH
  • Brevetoxin-10 (PbTx-10) R = -CH2CH(-CH3)CH2OH
  • Brevetoxin-2 (PbTx-2) R = -CH2C(=CH2)CHO
  • Brevetoxin-3 (PbTx-3) R = -CH2C(=CH2)CH2OH
  • Brevetoxin-8 (PbTx-8) R = -CH2COCH2Cl
  • Brevetoxin-9 (PbTx-9) R = -CH2CH(CH3)CH2OH

Other Brevetoxins:

  • Brevetoxin-5 (PbTx-5): like PbTx-2, but acetylated hydroxyl group in position 38.
  • Brevetoxin-6 (PbTx-6): like PbTx-2, but double bond 27-28 is epoxidated.

Brevetoxin-B was synthesized in 1995 by K. C. Nicolaou and coworkers in 123 steps with 91% average yield (final yield ~9·10−6) and in 2004 in a total of 90 steps with an average 93% yield for each step (0.14% overall).

K. C. Nicolaou and coworkers reported their synthesis of Brevetoxin-1 in 1998. In 2009, Michael Crimmins and co-workers reported their synthesis of Brevetoxin-1 as well.

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