dc.contributor.advisor | Minter, David E. | |
dc.contributor.author | Ochoa, Charles Israel | en_US |
dc.date.accessioned | 2018-08-20T20:38:23Z | |
dc.date.available | 2018-08-20T20:38:23Z | |
dc.date.created | 2018 | en_US |
dc.date.issued | 2018 | en_US |
dc.identifier | aleph-005058931 | en_US |
dc.identifier.uri | https://repository.tcu.edu/handle/116099117/22014 | |
dc.description.abstract | Hippadine and pratosine are lycorine-type pharmacologically active Amaryllidaceae alkaloids. Various total syntheses of these natural products have been developed. However, most of these synthetic routes require prohibitively expensive materials and/or achieve yields that are subpar, making these schemes unlikely to be used in an industrial setting. Herein, a better synthetic method for these two alkaloids starting with a 6,7-disubstituted isoquinoline is presented. The key step in the synthetic scheme centers around an intramolecular de Mayo photocyclization which involves a reaction between an alkene moiety in the isocarbostyril system and a 1,3-diketone (a functionalized tether on nitrogen), which forms a third ring in the structure of the molecule. When the photochemical reaction was attempted, an unexpected cyclic photoproduct was obtained; fortunately, this product is a cyclic hemiketal of the expected 1,5-dicarbonyl compound. A base-catalyzed aldol addition affords the final ring in the system; dehydration of this product affords a β-enone that can be transformed to a diene. Oxidation of the diene with DDQ affords the target natural products after simple chromatographic purification. This new synthetic pathway circumvents the need for catalysts that are either expensive or contain metals such as palladium or iridium; moreover, our method allows for the synthesis of various natural and unnatural alkaloids in high yields by modification of the N-tether. Additionally, the oxidation of a cyclic β,γ-enone to a phenol using Chloranil has been reported for the first time. This allows for an easy route to lycosprenine and 2-methoxyanhydrolycorinone, two natural products of the Amaryllidaceae family of plants. | |
dc.format.extent | 1 online resource (vi, 108 pages) : | en_US |
dc.format.medium | Format: Online | en_US |
dc.language.iso | eng | en_US |
dc.relation.ispartof | Texas Christian University dissertation | en_US |
dc.relation.ispartof | UMI thesis. | en_US |
dc.relation.ispartof | Texas Christian University dissertation. | en_US |
dc.subject.lcsh | Amaryllidaceae. | en_US |
dc.subject.lcsh | Alkaloids. | en_US |
dc.subject.lcsh | Photochemistry. | en_US |
dc.title | The total synthesis of hippadine and pratosine via an intramolecular de Mayo photocyclization | en_US |
dc.type | Text | en_US |
etd.degree.department | Department of Chemistry and Biochemistry | |
etd.degree.level | Doctoral | |
local.college | College of Science and Engineering | |
local.department | Chemistry and Biochemistry | |
local.academicunit | Department of Chemistry and Biochemistry | |
dc.type.genre | Dissertation | |
local.subjectarea | Chemistry and Biochemistry | |
etd.degree.name | Doctor of Philosophy | |
etd.degree.grantor | Texas Christian University | |