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Synthesis of Haptens for the Marine Toxin, Gymnodimine; Synthesis of Beta-lactone Fused Carbocycles and Nitrogen Heterocycles; Efforts Toward the Synthesis of the Proposed Structure of Thiolyngbyan

Contamination of seafood by marine toxins has been a consistent public health
problem. Gymnodimine (GYM) is a member of a family of spirocyclic imine containing
marine natural products which was shown to be highly toxic (LD50 96 mg/kg,
intraperitoneal injection); thus ensuring public safety requires stringent monitoring of
gymnodimine. Current detection methods for GYM and spirolides include the mouse
bioassay and LC-MS-based detection techniques which, however, have significant
limitations. Therefore, more efficient and convenient detection methods are required.
Building on our recently completed total synthesis of (-)-gymnodimine, the synthesis of
two haptens were targeted for eventual production of monoclonal antibodies (mAb) to be
used in an eventual Enzyme-Linked Immunosorbent Assay (ELISA) for gymnodimine.
As an extension of the intramolecular nucleophilic catalyzed aldol lactonization
(NCAL) process from aldehyde acid to keto acid substrates, carbocyclic and nitrogen
heterocyclic B-lactones were synthesized. Demonstration of the utility of the NCAL
process for keto acids was applied to the synthesis of dihydroplakevulin A and the core of
tussilagine. In addition, although initial attempts to develop guanidine catalysts for the
asymmetric NCAL process were unsuccessful, homobenzotetramisole (HBTM) was
found to be a suitable asymmetric catalyst for keto acid substrates.
Finally, synthetic studies toward the proposed structure of thiolyngbyan are
described. Thiolyngbyan was isolated from a blue-green algae and it exhibited antifungal
activity.

Identiferoai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-05-7768
Date2010 May 1900
CreatorsLee, Chang Suk
ContributorsRomo, Daniel
Source SetsTexas A and M University
Languageen_US
Detected LanguageEnglish
Typethesis, text
Formatapplication/pdf

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