Organic Chemistry Commons^™

An Efficient Method For The Chemoselective Synthesis Of Acylals From Aromatic Aldehydes Using Bismuth Triflate, Ram Mohan, Marc Carrigan, Kyle Eash, Matthew Oswald

Scholarship

Aromatic aldehydes are smoothly converted into the corresponding acylals in good yields in the presence of 0.10 mol% Bi(OTf)3•xH2O. Ketones are not affected under the reaction conditions. The highly catalytic nature of bismuth triflate and the fact that it is relatively non-toxic, easy to handle and insensitive to small amounts of air and moisture makes this procedure especially attractive for large-scale synthesis.

The Discovery-Oriented Approach To Organic Chemistry. 4. Epoxidation Of P-Methoxy-Trans-Β-Methylstyrene. An Exercise In 1H Nmr And 13C Nmr Spectroscopy For Sophomore Organic Laboratories, Ram Mohan, Rebecca Centko

Scholarship

Epoxidation of alkenes using peroxyacids is one of the most fundamental reactions in organic chemistry, yet there are very few examples of laboratory experiments that illustrate this important reaction. We have developed a discovery-oriented lab experiment that illustrates epoxidation of alkenes as well as the reactivity of epoxides toward acids. The experiment involves reaction of p-methoxy-trans-β-methylstyrene (trans-anethole) with m-chloroperoxybenzoic acid (MCPBA), in both the absence and presence of a buffer, followed by product identification using ¹H NMR, ¹³C NMR, and IR spectroscopy. The added element of discovery ensures that students' interest and enthusiasm are retained.

Deprotection Of Ketoximes Using Bismuth(Iii) Nitrate Pentahydrate, Ram Mohan, Bryce Nattier, Kyle Eash

Scholarship

Ketoximes undergo facile deprotection in acetone-H20 (9: 1) in the presence 01' 0.5 equivalents of Bi(N03h•5H20. Bismuth(III) nitrate is relatively non-toxic, insensitive to air and inexpensive. These features coupled with the use of a relatively nontoxic solvent system make this method an attractive alternative to existing routes for deprotection of ketoximes.

Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes

Journal of the Arkansas Academy of Science

No abstract provided.

Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave

Journal of the Arkansas Academy of Science

No abstract provided.

Meso-1, 2-Bis (Methylazo)-1, 2-Diphenylethane, Craig A. Bayse, Barry K. Carpenter, Rudy L. Luck

Chemistry & Biochemistry Faculty Publications

The title compound, meso-1,2-bis(methyldiazenyl)-1,2-diphenylethane, C16H18N4, is arranged in a disordered manner around an inversion point. The N—N atom distances in the azo group of 1.192 (8) and 1.195 (8) Å, and the C—C atom distances in the ethylene moiety at 1.512 (8) and 1.503 (8) Å in the two models [refined to 51.7 (6) and 48.3 (6)% occupancies] were not significantly different.

Chemical Constituents Of Desmos Dumosus, Roxb., Mazdida Sulaiman

Student Works (2000-2009)

The chemical content of the 'leaves and bark of Des mos dumosus has been carried out in this study. The leaves yielded nine isoquinoline type of alkaloids and two flavones. The isoquinoline alkaloids isolated were pronuciferine 37, stepharine 39, nomuciferine 40, (-) - 3 - hydroxynomuciferine 41, norlirioferine 42, asimilobine 43, liriodenine 44, lysicamine 45 and O - methylmoschatoline 46. The flavones were 5 - hydroxy - 6,7 - dimethoxyflavone 47 and 5 - hydroxy - 7,8 - dimethoxyflavone 48. The same flavones, 47 and 48 and the alkaloids 45 and 46 were also present in the bark of this …

Fourier Transform Raman Spectroscopy For Process Control In The Petroleum Industry, Kent Lawson Wise

Chemistry & Biochemistry Theses & Dissertations

As early as 1950, Raman spectroscopy was proposed as a method to determine aromatics and olefins in hydrocarbon mixtures. Until recently, extensive use of Raman spectroscopy in the characterization of hydrocarbons has not been practical due to several limitations. One early limitation to Raman analysis was the absence of a high intensity and stable excitation source. This problem has been overcome with the advent of lasers. Another limitation was the presence of fluorescence in hydrocarbon fuels when excited by visible lasers. However, the development of Fourier-transform Raman spectrometers now allows Raman spectra to be collected using near-IR lasers (e.g …

Risk Assessments For Chemical Stockpile Incinerators: Is The Supporting Guidance Adequate, Lawrence V. Tannenbaum

RISK: Health, Safety & Environment (1990-2002)

The author identifies potential deficiencies in guidance used in the United States for risk assessments of chemical weapons incinerators.

Fertilisers For Wine Grapes : An Information Package To Promote Efficient Fertiliser Practices, B. H. Goldspink, Neil Lantzke, Bob Paulin, Diana Louise Fisher, Colin Gordon, N. Cross, J M. Campbell-Clause

Bulletins 4000 -

No abstract provided.

9-Phenyl-3,4,4a,9a-Tetrahydrotriptycene And 9-Phenyl-1,2,3,4,4a,9a-Hexahydrotriptycene, John Masnovi, Shaoming Duan, Ronald J. Baker

Chemistry Faculty Publications

The structure of 9-phenyl-3,4,4a,9a-tetrahydrotriptycene, C26H22, (I), exhibits regiochemistry consistent with a stepwise mechanism for its formation from photocycloaddition of 1,3- cyclohexadiene and 9-phenylanthracene. Bond distances involving the bridgehead C atoms are similar in (I) and the hydrogenated derivative, 9-phenyl-1,2,3,4,4a,9a-hexahydrotriptycene, C26H24, (II), with bonds to the quaternary-C atoms exhibiting significant elongation [1.581 (2) A Ê in (I) and 1.585 (2) A Ê in (II)]. The molecular geometry precludes significant overlap between the phenyl groups and the interannular bonds in both compounds, indicating that the origin of the bond lengthening is steric in nature.

Double Cysteine Mutations In Staphylococcal Nuclease: The Effect Of Artificially Introduced Disulfide Bonds On Protein Structure And Stability, Anna Terry

Inquiry: The University of Arkansas Undergraduate Research Journal

Since a protein's function depends on its structure, basic research in protein structure facilitates the solution of many practical problems, such as the synthesis of more effective medicines. With this larger goal in sight, the purpose of this research project is to understand better the chemical principles that underlie protein structure and stability. Disulfide bonds are a potentially stabilizing feature of many proteins. They may form between cysteine residues in close proximity to one another if the orientation is favorable. Often found in proteins produced by organisms that grow at high temperatures, disulfide bonds may anchor side chains together, making …

Hammett Correlations Of The Amide Proton Chemical Shift In A Series Of 1-Tosyl-3-(4-Substituted Phenyl)Ureas, Frank L. Setliff, Melody K. Harrison

Journal of the Arkansas Academy of Science

No abstract provided.

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.

On The Vertical And Adiabatic Excitation Energies Of The 21a(G), State Of Trans-1,3-Butadiene, Jason Lappe '00, Robert J. Cave

All HMC Faculty Publications and Research

The excitation energy to the 2¹A_g state of trans-1,3-butadiene is examined using a variety of ab initio electronic structure techniques. While analogous states have been shown to be the lowest singlet excited states for all longer polyenes, for butadiene the position of the 2¹A_g state relative to the HOMO → LUMO excitation (1¹B_u) has been difficult to establish theoretically. We employ a variety of methods (CASSCF, CASPT2, MRSDCI, QDVPT) to examine both the vertical and adiabatic excitation energies for this state. At the ground-state geometry, the vertical excitation energies …

Studies Of Tryptophans In Membrane- Spanning "Walp" Peptides By Deuterium Nmr Spectroscopy, Nichole Reed

Inquiry: The University of Arkansas Undergraduate Research Journal

WALP pep tides of sequence acetyl-Gly-Trp-Trp-(Leu-Ala)-Trp-Trp-Ala-ethanolamine insert into lipid bilayers as membrane-spanning a-helices and modulate the lipid phase behavior as functions of n and the lipid acyl chain length. A key feature of the WALP peptides is the positioning of tryptophan (Trp) indole rings at the membrane/water interface. For the examples WALP19 with n = 6.5 and WALP23 with n = 8.5, we have labeled individual indoles with deuterium and incorporated the labeled peptides in oriented, hydrated bilayers of Dimyristoyl-phosphatidylcholine (DMPC). Deuterium NMR spectra from these samples show sharp resonances when the membrane normal is aligned either parallel (Beta = …

Hammett Correlations Of The Sulfonamide Proton Chemical Shift In A Series Of N-(Substituted Aryl)-P-Toluenesulfonamides, Frank L. Setliff, Tyson K. Spradlin

Journal of the Arkansas Academy of Science

No abstract provided.

Bismuth(Iii) Oxide Perchlorate Promoted Rearrangement Of Epoxides To Aldehydes And Ketones, Ram Mohan, Andrew Anderson, Jesse Blazek, Parie Garg, Brian Payne

Scholarship

Aryl-substituted epoxides and aliphatic epoxides with a tertiary epoxide carbon undergo smooth rearrangement in the presence of 10–50 mol% bismuth(III) oxide perchlorate, BiOClO₄•xH₂O, to give carbonyl compounds. The rearrangement is regioselective with aryl substituted epoxides and a single carbonyl compound arising from cleavage of benzylic C―O bond is formed. BiOClO_4•xH₂O is relatively non-toxic, insensitive to air and inexpensive, making this catalyst an attractive alternative to more corrosive and toxic Lewis acids such as BF₃•Et₂O or InCl₃ currently used to effect epoxide rearrangements.

Isolation Of Curcumin From Tumeric, Ram Mohan, Andrew Anderson, Matthew Mitchell

Scholarship

No abstract provided.

The Discovery-Oriented Approach To Organic Chemistry. 3. Boron-Trifluoride Catalyzed Rearrangement Of Cis- And Trans-Stilbene Oxides. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram Mohan, Erik Sgariglia, Regina Schopp, Kostas Gavardinas

Scholarship

Epoxides, or oxiranes, are among the most versatile intermediates in organic synthesis. Yet very few examples of laboratory experiments involving reactions of epoxides are to be found in lab texts. We have developed a discovery-oriented laboratory experiment that involves the rearrangement of both cis- and trans-stilbene oxides with boron trifluoride etherate. The identity of the product can be easily determined by ¹H NMR spectroscopy and, in case of the trans isomer, by preparation of the semicarbazone derivative as well. In spite of the simplicity of the experiment, the element of discovery ensures that student interest and enthusiasm are retained.

Reaction Of Alpine-Borane With Aldehydes: Reactivity Rate Assessment By Observation Of The Disappearance Of The Carbonyl N - Pi* Peak By Uv-Visible Spectroscopy, Layla Bland, Michael J. Panigot

Journal of the Arkansas Academy of Science

Due to an unexpectedly difficult reduction of indole-3-carbaldehyde and of isobutyraldehyde using the chiral reducing agent Alpine-Borane, the reactivity of several aliphatic, aromatic, and unsaturated aldehydes was investigated. This was done in order to determine whether there was a relationship between aldehyde structure and reduction rate. It was found that aliphatic aldehydes and aromatic aldehydes with no strongly electron-donating groups on the arene ring reduced faster than unsaturated aldehydes.

3-Hydroxykynurenine And 3-Hydroxyanthranilic Acid Generate Hydrogen Peroxide And Promote Α-Crystallin Cross Linking By Metal Ion Reduction, Lee E. Goldstein, Michael C. Leopold, Xudong Huang, Craig S. Atwood, Aleister J. Saunders, Mariana Hartshorn, James T. Lim, Et Al.

Chemistry Faculty Publications

The kynurenine pathway catabolite 3-hydroxykynurenine (3HK) and redox-active metals such as copper and iron are implicated in cataractogenesis. Here we investigate the reaction of kynurenine pathway catabolites with copper and iron, as well as interactions with the major lenticular structural proteins, the R-crystallins. The o-aminophenol kynurenine catabolites 3HK and 3-hydroxyanthranilic acid (3HAA) reduced Cu(II)>Fe(III) to Cu(I) and Fe(II), respectively, whereas quinolinic acid and the nonphenolic kynurenine catabolites kynurenine and anthranilic acid did not reduce either metal. Both 3HK and 3HAA generated superoxide and hydrogen peroxide in a copper-dependent manner. In addition, 3HK and 3HAA fostered copper-dependent R-crystallin cross-linking. 3HK- …

Photodecomposition Of Crystal Violet Dye In Water Solution And Suspensions Of Metal Oxides, Tatiana Yurievna Zakharian

Dissertations and Theses @ UNI

Photodecomposition and photodecolorization of crystal violet dye were studied in water solution, hydrogen peroxide solution and suspensions of metal oxides. Spectroscopic evidence for the formation of methylated pararosanilines and demethylated derivatives of Michler's ketone as the reaction intermediates was obtained for the photodecomposition of crystal violet in water solution. The mechanism of formation of the intermediates was discussed in terms of charges of individual atoms calculated using Spartan software.

Photooxidation of crystal violet was shown to occur faster in hydrogen peroxide solution due to the higher oxidation potential of hydrogen peroxide and hydroxyl radicals. A mechanism similar to photooxidation in …

Cu(Ii) Potentiation Of Alzheimer A Neurotoxicity, Xudong Huang, Math P. Cuajungco, Craig S. Atwood, Mariana A. Hartshorn, Joel D. A. Tyndall, Graeme R. Hanson, Karen C. Stokes, Michael C. Leopold, Et Al.

Chemistry Faculty Publications

Oxidative stress markers as well as high concentrations of copper are found in the vicinity of Aβ amyloid deposits in Alzheimer's disease. The neurotoxicity of Aβ in cell culture has been linked to H2O2generation by an unknown mechanism. We now report that Cu(II) markedly potentiates the neurotoxicity exhibited by Aβ in cell culture. The potentiation of toxicity is greatest for Aβ1–42 > Aβ1–40 ≫ mouse/rat Aβ1–40, corresponding to their relative capacities to reduce Cu(II) to Cu(I), form H2O2 in cell-free assays and to exhibit amyloid pathology. The copper complex of Aβ1–42 has a highly positive formal reduction potential (≈+500–550 mV versus …

Is Hyperconjugation Responsible For The "Gauche Effect" In 1-Fluoropropane And Other 2-Substituted-1-Fluoroethanes?, Paul R. Rablen, R. W. Hoffman, D. A. Hrovat, W. T. Borden

Chemistry & Biochemistry Faculty Works

The energies and geometries of a series of 2-substituted-1-fluoroethanes were computed at the MP2/6-311++G**(6D)//MP2/6-31+G* level of theory for both the maxima and minima of the rotation about the C-C bond. The results did not support the predictions of a hyperconjugative model, that both 1,2-difluoroethane and 1-chloro-2-fluoroethane would strongly prefer a gauche conformation, and that 1-fluoro-2-silylethane would strongly prefer an anti conformation. The existence of competing electrostatic interactions between the fluorine and the substituents at C-2 was indicated by the detailed geometries of the gauche conformers and by the calculated sensitivity of the gauche-anti energy differences to the presence of a …

The Discovery-Oriented Approach To Organic Chemistry. 2. Selectivity In Alcohol Oxidation. An Exercise In 1H Nmr Spectroscopy For Sophomore Organic Laboratories, Ram Mohan, Steven Shadwick

Scholarship

We have developed a simple oxidation experiment that presents the student with a puzzle and is a good exercise in ¹H NMR spectroscopy. The experiment, which illustrates the important concept of selectivity in organic synthesis, involves selective oxidation of a mixture of 1-heptanol and 2-heptanol using commercial swimming pool chlorine. ¹H NMR analysis of the product mixture allows the student to determine the selectivity exhibited by the reagent.

Media Coverage Of Epa's Draft Dioxin Reassessment Report, Sharon M. Friedman, Megan A. Fitzpatrick, Brenda P. Egolf

RISK: Health, Safety & Environment (1990-2002)

Using content analysis, the authors examine the utility of news media in democratic decision making.

The Discovery-Oriented Approach To Organic Chemistry 1. Nitration Of Unknown Organic Compounds. An Exercise In 1H Nmr And 13C Nmr Spectroscopy For Sophomore Organic Laboratories, Ram Mohan, Sonia Mcelveen, Kostas Gavardinas, Jean Stamberger

Scholarship

Nitration is one of the most fundamental reactions in organic chemistry. However, the majority of the nitration experiments found in the standard lab textbooks are of the "cookbook" variety and convey none of the excitement associated with discovery in experimental chemistry. We have developed two simple nitration experiments that present the student with a puzzle and are a good exercise in ¹H NMR and ¹³C NMR spectroscopy. ¹³ C NMR spectroscopy is a powerful structure elucidation tool and yet not many examples of the use of ¹³C NMR spectroscopy in organic lab experiments can be found. The …

Bulletin 4357 - Fertilisers For Pastures On Sandy Soils Of The Swan Coastal Plain, K. W. Angell

Bulletins 4000 -

When newly cleared for agriculture, the sandy soils of the Swan Coastal Plain were acutely deficient in phosphorus (P), nitrogen (N), and the trace elements copper ( Cu) and zinc (Zn) and sometimes molybdenum (Mo). Phosphorus deficiency was overcome by applying single superphosphate. Trace element deficiencies were overcome by adding Cu, Zn and Mo to superphosphate during manufacture, allowing P, Cu, Zn and Mo to be applied to the pasture in the one operation.

It was subsequently found that low sulphur (S) and potassium (K) were limiting production and persistence of subterranean clover-based pastures on the sandy soils of the …

[2,3:5,6]Dibenzo[2.2.2]Octa-2,5,7-Triene (C2/C) And [2,3:5,6]Dibenzo[2.2.2]Octa-2,5-Diene, Lary Burrows, John M. Masnovi, Ronald J. Baker

Chemistry Faculty Publications

Two barrelene homologs are reported. Strain in the bicyclic framework of [2,3:5,6]dibenzo[2.2.2]octa-2,5,7- triene, (I) (C16H12), which is manifest in the deviations from ideality of the bond angles in the central bicyclic ringoSyStem and compression of the double bond [1.312 (3)A], is reduced in the more saturated derivative, [2,3:5,6]dibenzo[2.2.2]octa-2,5-diene, (II) (CI6H14), with the corresponding single bond being 1.5380 (19)A. The formation of isomorphs of (I) in both chiral (C2) and achiral (C2/c) space groups has implications for asymmetric syntheses involving solid (I) which rely on a non-centrosymmetric space group.