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Organic chemistry

Medicinal and Pharmaceutical Chemistry

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Full-Text Articles in Medicinal-Pharmaceutical Chemistry

Synthesis Of Natural Compounds In Echinacea , Jaehoon Bae Jan 2006

Synthesis Of Natural Compounds In Echinacea , Jaehoon Bae

Retrospective Theses and Dissertations

In this dissertation, we have investigated the direct and efficient synthetic route to biologically active natural products. Chapter 1 describes the synthesis of some of the natural compounds in Echinacea. Several main constituents of the plant Echinacea have been synthesized for the first time. We have developed a direct and flexible route to amides and ketones in Echinacea. The synthesized natural products have been used for standard samples for the biological studies. Chapter 2 describes the new tandem strategy to construct bicyclic systems by a Diels-Alder/ene reaction and its application for the synthesis of Isoligularone. During this tandem reaction ...


New Palladium-Catalyzed Approaches To Heterocycles And Carbocycles, Qinhua Huang Jan 2004

New Palladium-Catalyzed Approaches To Heterocycles And Carbocycles, Qinhua Huang

Retrospective Theses and Dissertations

The tert-butylimines of o-(1-alkynyl)benzaldehydes and analogous pyridinecarbaldehydes have been cyclized under very mild reaction conditions in the presence of I2, ICl, PhSeCl, PhSCl and p-O2NC6H4SCl to give the corresponding halogen-, selenium- and sulfur-containing disubstituted isoquinolines and naphthyridines, respectively. Monosubstituted isoquinolines and naphthyridines have been synthesized by the metal-catalyzed ring closure of these same iminoalkynes. This methodology accommodates a variety of iminoalkynes and affords the anticipated heterocycles in moderate to excellent yields.;The Pd(II)-catalyzed cyclization of 2-(1-alkynyl)arylaldimines in the presence of various alkenes provides an efficient way to synthesize a variety of 4-(1-alkenyl)-3-arylisoquinolines ...


Synthesis Of Polycyclic Natural Products , Tuan Hoang Nguyen Jan 2003

Synthesis Of Polycyclic Natural Products , Tuan Hoang Nguyen

Retrospective Theses and Dissertations

Highly oxidized polycyclic natural products are abundant in nature and have diverse biological activities. Hyperforin has been identified as the sole constituent responsible for the antidepressant characteristic of St. John's wort. An approach to an oxidized bicyclic phloroglucin core of hyperforin is described. Puupehenone, a sesquiterpene found in marine sponges, has recently emerged as a strong candidate to treat tuberculosis. The synthesis of the BCD rings of puupehenone containing a quinone methide moiety is described.


New Methods For The Synthesis Of Natural Products , Alexey G. Melekhov Jan 1999

New Methods For The Synthesis Of Natural Products , Alexey G. Melekhov

Retrospective Theses and Dissertations

In this work we developed new approaches to three different classes of compounds. In the first chapter we employed PIFA as an oxidant to develop a direct route to pyrrolobenzodiazepines. We also developed a new way to generate acyl radicals by oxidative decarboxylation. The utility of this methodology was shown in the synthesis of 8-deoxy DC-81. In the second chapter we developed a five-step synthetic route to 1,4-phenanthrenequinones. We also used one of these phenanthrenequinones for the construction of an angularly-fused aromatic systems. In the third chapter we studied Lewis acid-mediated cyclizations of acyl quinones. We synthesized a precursor ...


Synthesis Of Diterpene Alkaloids , Tiberiu Mircea Siclovan Jan 1996

Synthesis Of Diterpene Alkaloids , Tiberiu Mircea Siclovan

Retrospective Theses and Dissertations

Aconitine, atisine and garrya type diterpene alkaloids show remarkable biological activity and have a number of structural features in common. Due to their complex structure, there is a discrepancy between progress made lately in the identification, isolation and characterization of new members of this family, on one hand, and successful efforts towards their total synthesis, on the other;Our synthetic studies led us to develop a highly reproducible synthesis of adamantane-containing compounds via the corresponding bridgehead anions;Studies on the application of functionalized bridgehead radicals in natural product synthesis resulted in the development of a versatile, mild and highly tolerant ...


Total Synthesis Of Angularly Fused Natural Products , Guohua Zhao Jan 1996

Total Synthesis Of Angularly Fused Natural Products , Guohua Zhao

Retrospective Theses and Dissertations

The synthesis of angularly fused quinone natural product G-2N has been achieved using a photoenolization reaction and a Diels-Alder reaction in the key carbon-carbon bond forming steps. This route is direct and flexible. It should be applicable to synthesis of other analogous natural products;The skeleton of colchicine has been achieved using a Diels-Alder reaction followed by an electrophilic addition to the A ring as key steps. Our synthetic approach is direct. It could provide an efficient entry to total synthesis of colchicine.


Synthetic Approaches To Huperzine A , Danette René Vines Jan 1994

Synthetic Approaches To Huperzine A , Danette René Vines

Retrospective Theses and Dissertations

The natural product huperzine A has been found to possess activity as a nootropic agent. Because of its memory facilitating effects, huperzine A represents a promising drug for the treatment of neurodegenerative diseases, such as Alzheimer's disease. As life expectancy increases, identifying and synthesizing drugs which treat cognitive dysfunction becomes a primary health objective;This study was undertaken to synthesize huperzine A, and to offer a direct route to improved analogs of huperzine A. A bicyclic amino ketone for the synthesis of huperzine A was prepared in six steps. The conjugate addition of metallated alkylpyridines afforded a direct route ...


Synthesis, Structure Features And Application Of Pro-Azaphsphatranes As Catalysts And Strong Non-Ionic Bases In Organic Synthesis , Jiansheng Tang Jan 1994

Synthesis, Structure Features And Application Of Pro-Azaphsphatranes As Catalysts And Strong Non-Ionic Bases In Organic Synthesis , Jiansheng Tang

Retrospective Theses and Dissertations

This dissertation describes the development of pro-azaphosphatranes ZP(MeNCH[subscript]2CH[subscript]2)[subscript]3N as versatile useful materials in organic synthesis;Pro-imidophosphatranes MeN= P(MeNCH[subscript]2CH[subscript]2)[subscript]3N and PhN= P(MeNCH[subscript]2CH[subscript]2)[subscript]3N, their corresponding acyclic analogues MeN= P(NMe[subscript]2)[subscript]3 and PhN= P(NMe[subscript]2)[subscript]3, and their conjugate acids as well as the conjugate acid of the commercially available non-ionic base P[subscript]4-t-Bu (i.e. t-BuN=P (N=P(NMe[subscript]2)[subscript]3][subscript]3) have been synthesized. Equilibria measured by [superscript ...