Walker JR, Merit JE, Thomas-Tran R, Tang DTY, Du Bois J. Divergent Synthesis of Natural Derivatives of (+)-Saxitoxin Including 11-Saxitoxinethanoic Acid.
Angew Chem Int Ed Engl 2019;
58:1689-1693. [PMID:
30488599 DOI:
10.1002/anie.201811717]
[Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Indexed: 11/06/2022]
Abstract
The bis-guanidinium toxins are a collection of natural products that display nanomolar potency against select isoforms of eukaryotic voltage-gated Na+ ion channels. We describe a synthetic strategy that enables access to four of these poisons, namely 11-saxitoxinethanoic acid, C13-acetoxy saxitoxin, decarbamoyl saxitoxin, and saxitoxin. Highlights of this work include an unusual Mislow-Evans rearrangement and a late-stage Stille ketene acetal coupling. The IC50 value of 11-saxitoxinethanoic acid was measured against rat NaV 1.4, and found to be 17.0 nm, similar to those of the sulfated toxins gonyautoxin II and III.
Collapse