Chemistry Commons^™

11-(2,2-Dimethylpropyl)-12-{2-[12-(2,2-Dimethylpropyl)- 9,10-Dihydro-9,10-Ethenoanthracen-11-Yl]- Ethyl}-9,10-Dihydro-9,10-Ethenoanthracene, Joseph P. Herres, Mark A. Forman, Kraig A. Wheeler, Glenn P.A. Yap

Faculty Research and Creative Activity

Reaction of tert-butyllithium with 11,12-dimethylene-9,10- dihydro-9,10-ethanoanthracene and 4,5-diiodopentacyclo- [4.3.0.02,4.03,8.05,7]nonane gives three products, one of which crystallizes from petroleum ether as the title compound, C44H46, (I). Molecules of (I) are positioned on inversion centers (Z0 = 0.5) in the space group P21/n and lack any discernible intermolecular interactions.

2,2':6',2"-Terpyridine 1,1"-Dioxide Dihydrate, Kraig A. Wheeler, Scott E. Mckay, Robert W. Lashlee Iii

Faculty Research and Creative Activity

No abstract provided.

Nature's Assembly Line Logic For Natural Products, Christopher T. Walsh, Ryan G. Kruger, David A. Vosburg

All HMC Faculty Publications and Research

Nature fashions a very large number of diverse products (molecular weights ranging from ca. 200 to 2000 daltons) from simple monomeric metabolites used in primary metabolism. These include polyketide scaffolds generated from the simple C₃ malonyl CoA and C₄ methylmalonyl CoA monomers and nonribosomal peptides made from both the 20 proteinogenic amino acids and dozens of nonpoteinogenic amino acids.¹ A large family of terpenoid skeletons are built from the Δ²- and Δ³-alkene isomers of the biological isoprene monomer, isoprenyl-pyrophosphate.²

A Theoretical Investigation Of Charge Transfer In Several Substituted Acridinium Ions, Jason Lappe '00, Robert J. Cave, Marshall D. Newton, I.V. Rostov

All HMC Faculty Publications and Research

We present calculations for various properties of the ground and excited states of several arylamine-substituted acridinium ion systems that have been studied experimentally. Using ab initio and semiempirical quantum mechanical methods together with the generalized Mulliken−Hush (GMH) model, we examine the excitation energies, dipole moment shifts, and electronic coupling elements for the vertical charge shift (CSh) processes in these systems. We also examine solvent effects on these properties using a dielectric continuum reaction field model. The results are in generally good agreement with available experimental results and indicate that there is strong electronic coupling in these systems over a wide …

Differential Tethering Of Log Phase Trypanosoma Brucei Onto Chemically Distinct Surfaces, Darrell R. Fry, Lydia Archuleta, Ashley Dunham, Justin Rains

Faculty Publications

Our long-term objective is to understand and model the motility of T. brucei. Obtaining high quality images of T. brucei that allow one to differentiate between cell body movement and flagallar movement is difficult with T. brucei because the flagellum is attached along the cell body. Currently, our approach his to tether T. brucei onto a microscope friendly surface. The contributions to the ISIS our progress to date. Specifically, we look at the adhesion density of T. brucei to numerous microscope friendly surfaces and at the optimum adhesion conditions for T. brucei.

Computational Study Of A Novel Dinuclear Metal Complex, Dragos Seghete

Inquiry: The University of Arkansas Undergraduate Research Journal

The first compound containing an M-H-M was recently reported by Vicic et al. With recent availability of large computational resources, molecular modeling has become a reliable tool for confirming experimental results. The novel dinuclear Ni complex [( dippm)2Ni2Br2]( 0 -H) was investigated in this work from a theoretical perspective. Full geometry optimization was carried on the dinuclear Ni complex at the DFT/B3LYP with the 6-31G* basis set. The result verifies the linear Ni-H-Ni bond. Two different starting structures that converged to the same geometry confirm that a global minimum was reached. The computed structure differs from the experimentally determined one …

A Solvent-Free Baeyer–Villiger Lactonization For The Undergraduate Organic Laboratory: Synthesis Of Γ-T-Butyl-Ε-Caprolactone, John J. Esteb, James N. Hohman, Diana E. Schladaminger, Anne M. Wilson

Scholarship and Professional Work - LAS

We present an experiment involving the Baeyer–Villiger oxidation reactionfor a first-year organic chemistry class. The Baeyer–Villiger reactionprovides an efficient method to convert ketones to esters or lactones. Most organictextbooks cover the Baeyer–Villiger reaction but owing to a lack of suitableexperiments, students seldom get to explore the reaction in the undergraduateteaching laboratory. In this experiment, m-chloroperoxybenzoic acid(m-CPBA) and4-tert-butylcyclohexanone are mixed together for 30 minutes under solvent-freeconditions to produce γ-t-butyl-ε-caprolactone in 95%yield. The solvent-free nature of this procedure greatly limits the quantityof waste generated by students and keeps costs low by removing the need for solvent.

Simulations Of Nanopore Formation And Phosphatidylserine Externalization In Lipid Membranes Subjected To A High-Intensity, Ultrashort Electric Pulse, Q. Hu, R. P. Joshi, K. H. Schoenbach

Bioelectrics Publications

A combined MD simulator and time dependent Laplace solver are used to analyze the electrically driven phosphatidylserine externalization process in cells. Time dependent details of nanopore formation at cell membranes in response to a high-intensity (100kV∕cm), ultrashort (10ns) electric pulse are also probed. Our results show that nanosized pores could typically be formed within about 5ns. These predictions are in very good agreement with recent experimental data. It is also demonstrated that defect formation and PS externalization in membranes should begin on the anode side. Finally, the simulations confirm that PS externalization is a nanopore facilitated event, rather than the …

Identification And Recovery Of An Asymmetric Calix[4]Arene Tetranitrile Derivative Using Liquid Chromatography And Mass Spectrometry, Benjamin Schazmann, Dermot Diamond

Articles

A simple analytical LC-MS (Liquid Chromatography Mass Spectrometry) method and associated instrumentation has been adapted for use by the organic chemist to yield mg quantities of target compound from a reaction mixture. Calix[4]arene 3 was identified as representing 51% of total peak area of a reaction mixture containing no less than 10 components, using LC-MS. This peak corresponded to a mass of 878.8, equivalent to a complex of 3 and an ammonium cation. Molecular models further rationalise this observation by showing that the asymmetric binding cavity of 3 is suitable for binding tetrahedral guests like the ammonium ion. By scaling …

Environment Friendly Organic Synthesis Using Bismuth Compounds. An Efficient Method For Carbonyl-Ene Reactions Catalyzed By Bismuth Triflate, Ram Mohan, Erin Anderson, Justin Ernat, Mai Nguyen, Ann Palma

Scholarship

Bismuth triflate (0.1 mol %) is a highly efficient catalyst for the cyclization of citronellal 1, a reaction that yields a ratio of 80:20 of isopulegol 2 and neoisopulegol 3. This methodology has also been extended to the synthesis of substituted piperidines. The bismuth triflate catalyzed ene reaction of aldehyde 4 gives a 70:30 mixture of piperidines 5 and 6. The advantages of these methods include the use of a highly efficient catalyst that is relatively nontoxic, cheap and easy to handle.

A Study Of Epoxyolefin Cyclizations Catalyzed By Bismuth Trifluoromethanesulfonate And Other Metal Triflates, Ram Mohan, Joshua Lacey, Peter Anzalone, Christopher Duncan, Matthew Hackert

Scholarship

Epoxyolefin cyclizations have attracted considerable interest due to their importance in biosynthetic pathways. Bismuth trifluoromethanesulfonate as well as several other metal triflates are shown to be highly effective (0.1 mol %) catalysts for the cyclization of geraniolene oxide. The product composition is found to be more dependent on solvent and substrate concentration than on the nature of the metal triflate. Cyclization products are favored in CH₂Cl₂ and under high dilution conditions. Ether solvents favored acyclic products.

The Discovery-Oriented Approach To Organic Chemistry. 6. Selective Reduction In Organic Chemistry: Reduction Of Aldehydes In The Presence Of Esters Using Sodium Borohydride, Ram Mohan, Ashvin Baru

Scholarship

Chemoselective reductions are valuable in organic synthesis and are routinely discussed in a sophomore organic chemistry course. Yet, there are few examples of laboratory experiments that illustrate such chemoselectivity. A reaction that is routinely discussed in sophomore organic chemistry is the selective reduction of aldehydes and ketones using sodium borohydride. Esters are typically not affected by NaBH₄. However, none of the lab experiments reported to date illustrate this chemoselectivity (1). We have developed a discovery-oriented lab experiment that illustrates the chemoselective nature of reductions using sodium borohydride. The experiments involve the reduction of vanillin acetate (Scheme I) …

Synthesis Of Novel Porphyrazines And Binding Studies To Dna Quadruplexes, Carlos Ramirez

Seton Hall University Dissertations and Theses (ETDs)

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Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan

Journal of the Arkansas Academy of Science

There is an intense interest in designing molecular systems which will absorb visible sunlight, initiate an electron transfer process, and ultimately convert the solar energy to useful chemical energy of fuels such as hydrogen produced from water. The zeolite-entrapped polypyridine complexes of divalent ruthenium hold promise as efficient photocatalysts for net charge separation and such efficiencies are further enhanced by organized incorporation of donor and acceptor components. This paper deals with the synthesis and spectroscopic investigation of zeolite-entrapped ruthenium polypyridine complexes which may be useful in the development of solar energy conversion schemes. The sensitizer molecules, such as Ru(bpy)3 2+ …

Synthesis And Characterization Of Membrane Anchored Peptides, Eugenia Christine Tsamis

Honors Program Theses

ln KW ALP23 peptides containing Lysine and Trp, as the Trps were moved further in towards the center of the bilayer, Lys became the dominant anchoring residue (1). The goal of this project was to determine whether Arg exhibits snorkeling behavior similar to Lys, and is able to anchor the peptide in the membrane despite the repositioning of Trp in the RWALP peptides. Several candidate R W ALP23 peptides containing Tryptophan and Arginine with an alternating LeucineAlanine backbone were synthesized successfully. They were then studied by HPLC, CD, and MALDI-TOF Mass Spectrometry to investigate the anchoring roles of Arg and …

Structural Study Of Disease Related Proteins, Ayse Sinem Ozyurt

Electronic Theses and Dissertations

The availability of complete sequences for the genomes of many organisms changes the researcher's attention from genome sequencing to finding the function of gene products, the proteins. The three dimensional (3D) structure of a protein is helpful to understand its function, because tertiary structure is more conserved in evolution than sequence. The 3D structures can be found quickly by using high-throughput (HT) methods for protein expression, purification, characterization and structure determination. This process is very challenging in every step. Therefore we selected nearly 200 cancer related proteins as targets to see the difficulties in trying to determine the web predicted …

9-Ethyl-3-Methyl-1, 6-Dinitrocarbazole, Erol Asker, John Masnovi

Chemistry Faculty Publications

No abstract provided.

Semi-Biosynthesis Of Dna Nanostructures, Aoune Barhoumi

Theses, Dissertations and Capstones

Nanotechnology refers to all technologies aiming to build objects, make measurements, and carry out processes on the nanometer length scale. In particular molecular nanotechnology exemplifies the so-called "bottom up" approach, which is briefly defined as the ability to build useful nanostructures with molecular precision, such as molecular machinery. Such capability for controlling matter at the molecular scale has always been the dream of scientists.

All living things are nanofoundries. Billions of years ago, nature perfectly provided all living things with the most accurate biological nanotechnology systems. Cellular internal dynamics, communicative resonance in protein conformational states, viruses as microreplicators, nanoscale life …

2,2':6',2"-Terpyridine N,N',N"-Trioxide, Kraig A. Wheeler, Scott E. Mckay, Silas C. Blackstock

Faculty Research and Creative Activity

No abstract provided.

The Effects Of Multiple Mutations In The Hydrophobic Core Upon The Stability Of Staphylococcal Nuclease, Rebecca L. Danforth

Inquiry: The University of Arkansas Undergraduate Research Journal

Previous work in the laboratory of my research advisor, Dr. Wesley Stites, has investigated the core packing of the protein staphylococcal nuclease. The core of a protein is critical in determining a protein's structure and stability. The hydrophobicity of the core has long been thought to be the principal driving force for folding, but recent work in the Stites lab has shown that optimization of van der Waals contacts and minimization of cavities, in our shorthand term, packing, is at least as energetically important. We are building upon this information in our attempt to better pack the protein core. If …

Solvent-Free Conversion Of Alpha-Naphthaldehyde To 1-Naphthoic Acid And 1-Naphthalenemethanol: Application Of The Cannizzaro Reaction, John J. Esteb, Keith M. Glogorich, Stacey A. O'Reilly

Scholarship and Professional Work - LAS

The Cannizzaro reaction is routinely covered in organic textbooks, but owing to the shortage of suitable procedures for the undergraduate teaching laboratory, this reaction is seldom performed in a first-year organic chemistry class. In this experiment, powdered potassium hydroxide and α-naphthaldehyde are heated under solvent-free conditions to produce 1-naphthoic acid and 1-naphthalenemethanol in 86% and 79% yields, respectively. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to the typical solvent-based method of preparation. Note:Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information …

Simple Epoxide Formation For The Organic Laboratory Using Oxone, John J. Esteb

Scholarship and Professional Work - LAS

We present an epoxide formation experiment for a second-semester organic chemistry laboratory. This oxidation utilizes Oxone, a commercially available oxidizing agent, in the industrially relevant process of epoxide formation. The oxidant performing the oxidation is dimethyldioxirane, which is formed in situ. This experiment demonstrates a simple synthesis of an epoxide and formation of a secondary oxidizing agent.

Cautionary Comments (Author Response), John J. Esteb, Anne M. Wilson

Scholarship and Professional Work - LAS

Reply to concerns about a safety factor in the paper, “A Solvent-Free Oxidation of Alcohols in an Organic Laboratory."

Bismuth Compounds In Organic Synthesis. Bismuth Nitrate Catalyzed Chemoselective Synthesis Of Acylals From Aromatic Aldehydes, Ram Mohan, David Aggen, Joshua Arnold, Patrick Hayes, Nathaniel Smoter

Scholarship

Aromatic aldehydes are smoothly converted into the corresponding acylals in good yields in the presence of 3–10 mol% Bi(NO₃)₃•5H₂O. Ketones are not affected under the reaction conditions. The relatively non-toxic nature of the catalyst, its ease of handling, easy availability and low cost make this procedure especially attractive for large-scale synthesis.

Environment-Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Triflate Catalyzed Synthesis Of Substituted 3,4-Dihydro-2h-L-Benzopyrans, Ram Mohan, Mai Nguyen, Joshua Arnold, Katherine Peterson

Scholarship

A highly catalytic method for the synthesis of dihydrobenzopyrans from salicylaldehydes has been developed. An extension of this method to the synthesis of a pyrano [2,3,b]benzopyran has also been achieved. Bi(OTf)₃.xH₂O (1< x < 4) (0.1mol%) smoothly catalyzes the condensation of substituted salicylaldehydes with 2,2-dimethoxypropane to give the corresponding substituted 3,4-dihydro-2H-1-benzopyrans as a mixture of diastereomers (9:1) in moderate yields. The relative configuration of the methoxy groups in the two diastereomers was established by NOE experiments. The advantages of this method include the use of an easy to handle, inexpensive and relatively non-toxic catalyst.

Lipid-Lowering Effects Of Ethyl 2-Phenacyl-3-Aryl-1h-Pyrrole- 4-Carboxylates In Rodents, Justin M. Holub, Kathy O'Toole-Colin, Adam Getzel, Anthony Argenti, Michael A. Evans, Daniel C. Smith, Gerard A. Dalglish, Shahzad Rifat, Donna L. Wilson, Brett M, Taylor, Ulander Miott, Josephine Glersaye, Kam Suet Lam, Bryan J. Mccranor, Joshua D. Berkowitz, Robert B. Miller, John R. Lukens, Keith Krumpe, John T. Gupton, Bruce S. Burnham

Chemistry Faculty Publications

A series of substituted 2-phenacyl-3-phenyl-1H-pyrrole-4-carboxylates were prepared from substituted acetophenones in 6 steps. The final condensations between a chloroenal and an aminoketone were carried out under neutral conditions in parallel to yield the series listed below. Selected pyrrole derivatives proved to be potent hypolipidemic agents lowering serum triglyceride concentrations in CF-1 male mice after 14 days of I.P. administration. One agent orally lowered serum cholesterol in Sprague-Dawley male rats at 2mg/kg/day after 14 days. The agents demonstrated a lowering of mouse serum LDL- cholesterol levels and selected compounds showed an elevation of serum HDL-cholesterol levels. The cholesterol concentrations in the …

Synthesis Of Novel [3, 2-B] Indole Fused Oleanolic Acids As Potential Inhibitors Of Cell Proliferation, Heather J. Finlay, Tadashi Honda, Gordon W. Gribble

Dartmouth Scholarship

Seven new indole-fused oleanolic acid derivatives were synthesized from oleanolic acid for their ability to inhibit cell proliferation in NRP. 152 cells.

A Solvent-Free Oxidation Of Alcohols In An Organic Laboratory, John J. Esteb, Michael W. Schelle, Anne N. Wilson

Scholarship and Professional Work - LAS

An oxidation experiment for a first-year organic chemistry class is presented. This oxidation utilizes a solid mixture of CuSO4•5H2O and KMnO4 prepared by mortar and pestle. The oxidations take place under solvent-free conditions and near quantitative yields are obtained for the reactions. Thin-layer chromatography is used to monitor the progress of the reaction. This experiment provides for the simple oxidation of a secondary alcohol to a ketone using a relatively nontoxic oxidizing agent under solvent-free conditions.

On The Existence And Stability Of Liquid Water On The Martian Surface, Justin Thompson

Inquiry: The University of Arkansas Undergraduate Research Journal

Present-day Mars is thought to be a frozen desert on which liquid water is not likely to be found. The prevailing assumption has been that due to average temperatures below 273 K and atmospheric pressures at or below water's triple-point vapor pressure of 6.1 mbar, the existence of liquid water as an equilibrium phase at or near the surface is impossible at the present epoch. However, there is substantial evidence that liquid water has existed in the past and may presently still exist on or directly below the Martian surface. I conducted simulation experiments in the Andromeda planetary environmental chamber …

A Solvent-Free Claisen Condensation Reaction For The Organic Laboratory, John J. Esteb, Matthew B. Stockton

Scholarship and Professional Work - LAS

An experiment involving the Claisen condensation reaction for a first-year organic chemistry laboratory is presented. Claisen condensations are routinely covered in organic textbooks but owing to the long reaction times required to reach equilibrium in solution they are seldom explored in the undergraduate teaching laboratory. In this experiment, potassium tert-butoxide and ethyl phenylacetate are heated to 100 °C for 30 minutes under solvent-free conditions to produce 2,4-diphenyl acetoacetate in 80% yield. The solvent-free nature of this procedure greatly reduces the quantity of waste generated by students relative to typical carbonyl condensation experiments.