The pyrrole imidazole alkaloids (PIA) is an ever-growing family of structurally
related natural products isolated from several species of sponges which now features
more than one hundred memebrs. Their complex molecular architectures, and in some
cases, significant biological activities, have made these alkaloids the synthetic targets of a
number of research groups across the world. In our approach, following early
biosynthetic proposal by Kinnel and Scheuer and Al-Mourabit and Potier, it was
envisioned that several of these alkaloids, namely palau’amine, axinellamine,
konbu’acidin, styloguanidine and massadine, could be derived from a common
chlorocyclopentane precursor through different modes of intramolecular cyclization.
Building on the work done previously in our research group by Dr. Anja Dilley, Dr.
Paul Dransfield, and Dr. Shaohui Wang, my investigations led to the synthesis of the
angular aza-triquinane core of axinellamine and the peculiar transazabicyclo[
3.3.0]octane core of palau’amine. In my further studies mono- and bis-pyrrole
advanced intermediates were synthesized that contain the complete carbon framework of
the target natural products. However, attempts to induce the pivotal, potentially
biomimetic cyclizations expected to deliver the cores of the target alkaloids proved to be
rather challenging, resulting in inconsistent and irreproducible results and leading to the
exploration of an alternative, “abiotic” approach.
My efforts in this direction resulted in the synthesis of a pentacyclic enamine
precursor to styloguanidine and a pentacyclic carbinolamine suitable for the synthesis of
palau’amine. Final attempts to complete the target natural products were however
unsuccessful.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-08-8217 |
| Date | 2010 August 1900 |
| Creators | Zancanella, Manuel |
| Contributors | Romo, Daniel |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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