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Articles 151 - 176 of 176

Full-Text Articles in Medicinal-Pharmaceutical Chemistry

Controlled Assembly Of Rodlike Viruses With Polymers, T. Li, L. Wu, N. Suthiwangcharoen, M. A. Bruckman, D. Cash, J. S. Hudson, Soumitra Ghoshroy, Qian Wang Jan 2009

Controlled Assembly Of Rodlike Viruses With Polymers, T. Li, L. Wu, N. Suthiwangcharoen, M. A. Bruckman, D. Cash, J. S. Hudson, Soumitra Ghoshroy, Qian Wang

Faculty Publications

A practical method to assemble rodlike tobacco mosaic virus and bacteriophage M13 with polymers was developed, which afforded a 3D core–shell composite with morphological control.


Preparation And Characterization Of Some Substituted Benzyl N-Nitrosocarbamates Containing An N-2-(Methylthio)Ethyl Or A Bis(2-Aminoethyl)Sulfide Functionality, Satya Venkata, Eric Shamo, Vladimir Benin Jan 2009

Preparation And Characterization Of Some Substituted Benzyl N-Nitrosocarbamates Containing An N-2-(Methylthio)Ethyl Or A Bis(2-Aminoethyl)Sulfide Functionality, Satya Venkata, Eric Shamo, Vladimir Benin

Chemistry Faculty Publications

The synthesis and characterization of some substituted benzyl N-nitrosocarbamates with an N-2-(methylthio)ethyl or a bis(2-aminoethyl)sulfide functionality is reported, as a part of a long-term goal to design and prepare novel photolabile structures that could be used as substances for controlled release of alkylating and/or crosslinking agents. The synthesis was accomplished by reaction of benzyl chloroformates with the corresponding amines, resulting in the preparation of carbamates. The latter were subsequently nitrosated, utilizing two different N-nitrosation methods, to yield the target structures.


Generation Of Novel Pikromycin Antibiotic Products Through Mutasynthesis, Shuchi Gupta, Venkatraman Lakshmanan, Beom Seok Kim, Robert Fecik, Kevin A. Reynolds Jan 2009

Generation Of Novel Pikromycin Antibiotic Products Through Mutasynthesis, Shuchi Gupta, Venkatraman Lakshmanan, Beom Seok Kim, Robert Fecik, Kevin A. Reynolds

Chemistry Faculty Publications and Presentations

Mutasynthesis in pikromycin PKS: The amenability of pikromycin polyketide synthase to mutational biosynthesis has been demonstrated. A natural triketide and its analogues, activated as N-acetyl-cysteamine thioesters, were synthesized and fed to a pikAI-deleted strain; this led to the production of new antibiotics. A vinyl analogue was found to have better antibacterial activity than pikromycin.


Synthesis Of Facial Amphiphile 3,7-Diamino-5Α-Cholestane Derivatives As A Molecular Receptor, Md Wasi Ahmad, Young Mee Jung, Sharaf Nawaz Khan, Hong Seok Kim Dec 2008

Synthesis Of Facial Amphiphile 3,7-Diamino-5Α-Cholestane Derivatives As A Molecular Receptor, Md Wasi Ahmad, Young Mee Jung, Sharaf Nawaz Khan, Hong Seok Kim

Dr. Mohammad Wasi Ahmad (Md Wasi Ahmad)

A series of facial amphiphiles 3,7-diaminocholestane were synthesized from 3,7-diketocholestane via 2 sequential reductive aminations and anion recognition was evaluated with acetate, chloride, bromide, fluoride and phosphate anions. The stereo-selective reductive amination protocol was utilized to synthesized facial amphiphiles afforded receptors in high yields. The molecular receptor 2 showed the highest binding constant with acetate in a 1:1 ratio.


Preparation Of Halogenated Derivatives Of Thiazolo[5,4-D]Thiazole Via Direct Electrophilic Aromatic Substitution, Vladimir Benin, Alan T. Yeates, Douglas Dudis May 2008

Preparation Of Halogenated Derivatives Of Thiazolo[5,4-D]Thiazole Via Direct Electrophilic Aromatic Substitution, Vladimir Benin, Alan T. Yeates, Douglas Dudis

Chemistry Faculty Publications

Chlorination and bromination reactions of thiazolo[5,4-d]thiazole led to the generation of its mono- and dihalogenated derivatives. These are the first instances of successful direct electrophilic aromatic substitution in the thiazolo[5,4-d]thiazole ring system. X-ray analysis demonstrates that both 2-bromothiazolo[5,4-d]-thiazole and 2,5-dibromothiazolo[5,4-d]thiazole are planar structures, with strongly manifested π-stacking in the solid state. Theoretical analysis of the pyridine-catalyzed halogenation (MP2/6-31+G(d) and B3LYP/6-31+G(d)calculations) reveals that introduction of one halogen actually leads to a slightly enhanced reactivity towards further halogenation ...


C–N Bond Rotation And E–Z Isomerism In Some N-Benzyl-N-Methylcarbamoyl Chlorides: A Dft Study, Michael Horwath, Vladimir Benin Feb 2008

C–N Bond Rotation And E–Z Isomerism In Some N-Benzyl-N-Methylcarbamoyl Chlorides: A Dft Study, Michael Horwath, Vladimir Benin

Chemistry Faculty Publications

The current report presents the first theoretical study of the restricted CN bond rotation in carbamoyl chlorides. Several N-benzyl-N-methylcarbamoyl chlorides were investigated, with varying pattern of substitution in the aromatic ring. Optimizations and frequency calculations were conducted employing DFT at the B3LYP/6-31+G(d) level of theory. Each of the studied structures exhibits a pair of rotamers (s-Z and s-E), generated upon rotation around the C(O)N bond. The s-E isomer is the global minimum in every case, but the preference for it is usually less than 1 kcal/mol. Two possible ...


N-Acetyl-2-Hydroxy-N '- Methoxy(1-Methylindol-2-Yl)Methyl Benzohydrazide, Azhar Ariffin, Ng S. W., Yehye W. A., Rahman N. A. Jan 2008

N-Acetyl-2-Hydroxy-N '- Methoxy(1-Methylindol-2-Yl)Methyl Benzohydrazide, Azhar Ariffin, Ng S. W., Yehye W. A., Rahman N. A.

Azhar Ariffin

In the crystal structure of the title Schiff-base, C(20)H(21)N(3)O(4), the amino group forms an N-H center dot center dot center dot O hydrogen bond to the acetyl group of an adjacent molecule, forming a zigzag chain. The 2-hydroxy group is internally hydrogen bonded to the amido group though an O-H center dot center dot center dot O hydrogen bond.


Oriented Cell Growth On Self-Assembled Bacteriophage M13 Thin Films, J. Rong, L. A. Lee, K. Li, B. Harp, C. M. Mello, Z. Niu, Qian Wang Jan 2008

Oriented Cell Growth On Self-Assembled Bacteriophage M13 Thin Films, J. Rong, L. A. Lee, K. Li, B. Harp, C. M. Mello, Z. Niu, Qian Wang

Faculty Publications

Fibrillar M13 bacteriophages were used as basic building blocks to generate thin films with aligned nanogrooves, which, upon chemical grafting with RGD peptides, guide cell alignment and orient the cell outgrowth along defined directions.


New Cyclic Peptides Via Ring-Closing Metathesis Reactions And Their Anti-Bacterial Activities, Timothy P. Boyle, John B. Bremner, Jonathan Coates, John Deadman, Paul A. Keller, Stephen G. Pyne, David I. Rhodes Jan 2008

New Cyclic Peptides Via Ring-Closing Metathesis Reactions And Their Anti-Bacterial Activities, Timothy P. Boyle, John B. Bremner, Jonathan Coates, John Deadman, Paul A. Keller, Stephen G. Pyne, David I. Rhodes

Faculty of Science - Papers (Archive)

As part of a program investigating cyclic peptides with an internal aromatic hydrophobic scaffold as potential novel anti-bacterial agents, we explored the synthesis of simple tyrosine-based systems. These were prepared via key intermediates containing internal allylglycine and allyltyrosine residues for subsequent ring closing metathesis reactions. Although the resulting anti-bacterial activity against Staphylococcus aureus was modest, this represents a novel and simple route to this class of compounds. One intermediate acyclic dipeptide precursor showed good activity against S. aureus with an MIC of 7.8 µg/mL.


Unsymmetric Aryl–Alkyl Disulfide Growth Inhibitors Of Methicillin-Resistant Staphylococcus Aureus And Bacillus Anthracis, Edward Turos, Kevin D. Revell, Praveen Ramaraju, Danielle A. Gergeres, Kerriann Greenhalgh, Ashley Young, Nalini Sathyanarayan, Sonja Dickey, Daniel Lim, Mamoun M. Alhamadsheh, Kevin A. Reynolds Jan 2008

Unsymmetric Aryl–Alkyl Disulfide Growth Inhibitors Of Methicillin-Resistant Staphylococcus Aureus And Bacillus Anthracis, Edward Turos, Kevin D. Revell, Praveen Ramaraju, Danielle A. Gergeres, Kerriann Greenhalgh, Ashley Young, Nalini Sathyanarayan, Sonja Dickey, Daniel Lim, Mamoun M. Alhamadsheh, Kevin A. Reynolds

Chemistry Faculty Publications and Presentations

This study describes the antibacterial properties of synthetically-produced mixed aryl alkyl disulfide compounds as a means to control the growth of Staphylococcus aureus and Bacillus anthracis. Some of these compounds exerted strong in vitro bioactivity. Our results indicate that among the twelve different aryl substituents examined, nitrophenyl derivatives provide the strongest antibiotic activities. This may be the result of electronic activation of the arylthio moiety as a leaving group for nucleophilic attack on the disulfide bond. Small alkyl residues on the other sulfur provide the best activity as well, which for different bacteria appears to be somewhat dependent on the ...


Secondary N-Nitrosocarbamate Anions: Structure And Alkylation Reactions. A Dft Study, Vladimir Benin May 2006

Secondary N-Nitrosocarbamate Anions: Structure And Alkylation Reactions. A Dft Study, Vladimir Benin

Chemistry Faculty Publications

The current article reports theoretical studies (DFT: B3LYP/6-31+G(d)) on the structure and alkylation reactions of the anions of some secondary N-nitrosocarbamates, a class of ambident nucleophiles whose chemistry has been little explored. Several anions (1–4), with an increasing size of the carbamate alkyl (aryl) group were investigated, in an attempt to establish the influence of the size of that group on the thermal stability and regioselectivity of alkylation of the title anions. The conclusion is that thermal stability and the mode of reaction are affected significantly only in the presence of very large and branched ...


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 ...


Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin Jan 2006

Preparation, Characterization And Dft Studies Of Some New N-Nitrosocarbamates And N-Nitrosoureas, Ragavan Narayanan, Helene Hedian, Eric Shamo, Vladimir Benin

Chemistry Faculty Publications

We are presenting the preparation, characterization and density functional theory (DFT) studies {B3LYP/6-31+G(d)) of several reiated classes of N-nitrosocarbamates and N-nitrosoureas. The iong-range goal is the design and preparation of compounds, which would undergo photochemical or hydrolytic decomposition, to yield stabilized cyclic cations that can serve as alkylating agents at various nucleophilic centers, including DNA bases.


Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin Jan 2006

Preparation Of Some Substituted Terephthalic Acids, Susanna Branion, Vladimir Benin

Chemistry Faculty Publications

We report in detail the preparation of two substituted terephthalic acids: 2‐sulfomethylterephthalic acid (1) and 2‐phosphonoterephthalic acid (2). Efficient, short syntheses have been developed for both compounds. They are potentially useful monomers for construction of acid‐pendant polymer chains.


Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin May 2005

Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin

Chemistry Faculty Publications

The present report describes the preparation and characterization of several N-2-(trimethylsilyl)ethyl-N-nitrosocarbamates, designed as precursors to thermally unstable secondary N-nitrosocarbamate anions via fluoride-assisted cleavage. X-ray structural studies demonstrate that the core N-nitrosocarbamate moiety has a nearly planar geometry, with an s-E orientation at the N–N bond. DFT calculations (B3LYP/6-31+G(d)) reproduce accurately the structural features of the title compounds and detailed conformational analysis at the same level of theory addresses the long-standing issue of preferred geometries for three classes of related structures: N-nitrosocarbamates, N-nitrosoureas and N-nitrosoamides. Desilylation ...


Enantiomeric Chromatographic Separations And Ionic Liquids , Jie Ding Jan 2005

Enantiomeric Chromatographic Separations And Ionic Liquids , Jie Ding

Retrospective Theses and Dissertations

The chiral nature of compounds contributes to their bioactivity and their various pharmaceutical/industrial uses. As a result, the Food and Drug Administration (FDA) has implemented policies for analyzing the enantiomers of chiral compounds. Gas chromatography (GC) and liquid chromatography (LC) utilizing chiral stationary phases are the two most commonly used methods to achieve direct enantiomeric separations of chiral compounds. The first part of this dissertation includes a review of direct separation of enantiomers in gas and liquid chromatography, an example of the enantiomeric separation of various racemic sulfoxides and sulfinate esters on four derivatized cyclodextrin chiral stationary phases using ...


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.


Preparation Of An Electrophilic 3-Methylindole Derivative: Difficulties In Forming A Stable, Suitable Material For The Preparation Of Tryptophan, Jason Boggs, Mariah Mcmasters, Robert W. Curley Jr., Michael J. Panigot Jan 2000

Preparation Of An Electrophilic 3-Methylindole Derivative: Difficulties In Forming A Stable, Suitable Material For The Preparation Of Tryptophan, Jason Boggs, Mariah Mcmasters, Robert W. Curley Jr., Michael J. Panigot

Journal of the Arkansas Academy of Science

In an attempt to prepare stereoselectively beta-deuterated tryptophan, N-protected indole-3-methanol compounds were prepared with model studies being done on undeuterated material. Conversion of these compounds to electrophilic species proved exceptionally difficult and resulted in very low yields or recovered starting material only. A summary of the current results utilizing N-tosyl indole-3-methanol will be presented as well as efforts using N-Boc indole-3-methanol.


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 ...


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.


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 ...


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 ...


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 ...


Synthetic Dibenzofurans Structurally Related To Known Analgesics, Frederick Albert Yeoman Jan 1944

Synthetic Dibenzofurans Structurally Related To Known Analgesics, Frederick Albert Yeoman

Retrospective Theses and Dissertations

No abstract provided.


Some Correlations Between Hypnotic Action And Chemical Constitution , William Glen Bywater Jan 1934

Some Correlations Between Hypnotic Action And Chemical Constitution , William Glen Bywater

Retrospective Theses and Dissertations

A review of theories of narcosis has been made, and some correlations between constitution and activity have been presented for the aliphatic hypnotics;The close and important relationship of dibenzofuran and its derivatives to morphine has been discussed. The following derivatives to morphine has been discussed. The following derivatives to morphine has been discussed. The following derivatives of dibenzofuran haven been prepared for use in physiological tests: 2-, 3-, and 4-amino-, 2- and 3-hydroxy-dibenzofuran, and 2- and 3-dibenzofurancarboxylic acids;A necessary study of nuclear substitution in dibenzofuran has been made prior to the preparation of derivatives for physiological tests. It ...