Physical Sciences and Mathematics Commons^™

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Vladimir Benin

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing …

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

Vladimir Benin

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 studies demonstrate that both the …

Understanding Organic Film Behavior On Alloy And Metal Oxides, Aparna Raman, Rosalynn Quiñones, Lisa Barriger, Rachel Eastman, Arash Parsi, Ellen Gawalt

Rosalynn Quiñones-Fernández

Native oxide surfaces of stainless steel 316L and Nitinol alloys and their constituent metal oxides, namely nickel, chromium, molybdenum, manganese, iron, and titanium, were modified with long chain organic acids to better understand organic film formation. The adhesion and stability of films of octadecylphosphonic acid, octadecylhydroxamic acid, octadecylcarboxylic acid, and octadecylsulfonic acid on these substrates were examined in this study. The films formed on these surfaces were analyzed by diffuse reflectance infrared Fourier transform spectroscopy, contact angle goniometry, atomic force microscopy, and matrix-assisted laser desorption ionization mass spectrometry. The effect of the acidity of the organic moiety and substrate composition …

Linear Free Energy Relationship And Kinetic Isotope Effects As Measures For The Transition State Variation. A Computational Study, Salai Ammal, M. Mishima, H. Yamataka

Salai C. Ammal

No abstract provided.

Enols Of Substituted Cyanomalonamides, A. Basheer, H. Yamataka, Salai Ammal, Z. Rappoport

Salai C. Ammal

No abstract provided.

Isolation Of Thymol From Carom Seeds, Ram Mohan, Leonard Onsen

Ram S. Mohan

A simple protocol for the isolation and characterization of thymol from Trachyspermum ammi, commonly known as Bishop’s weed or carom seed, is reported. Carom seeds are commonly used in Indian cooking as a digestive aid, to treat stomach pain, and for their carminative properties. The protocol, developed as an experiment for introductory organic chemistry laboratories, provides instruction in natural product isolation, chromatographic techniques, acid-base concepts and NMR spectroscopy.

An Integrated Systems Approach To Deconstructing Glycosylation, L. Mahal, John Rakus, Kanoelani Pilobello, P. Agrawal

John F. Rakus

Glycosylation involves the post-translational addition of carbohydrates to protein molecules and is an intricate and indispensable biochemical process. Study of this complicated network of interactions is hindered by the lack of a coding template analogous to the genetic code, and by the vast structural complexity inherent to carbohydrate polymers. We use lectins (non-enzymatic carbohydrate-binding proteins of non-immunological origin) as microarray probes to identify carbohydrate features expressed on cellular surfaces. Specifically, we utilized lectin microarray technology to investigate the differences in carbohydrates expressed by the cell lines of the Nation Cancer Institute’s NCI-60 panel. Our investigation identified tissue-specific expression differences in …

Evolution Of Enzymatic Activities In The Enolase Superfamily: L-Rhamnonate Dehydratase, John Rakus, Alexander Fedorov, Elena Fedorov, Margaret Glasner, Brian Hubbard, Joseph Delli, Patricia Babbitt, Steven Almo, John Gerlt

John F. Rakus

The L-rhamnonate dehydratase (RhamD) function was assigned to a previously uncharacterized family in the mechanistically diverse enolase superfamily that is encoded by the genome of Escherichia coli K-12. We screened a library of acid sugars to discover that the enzyme displays a promiscuous substrate specificity: L-rhamnonate (6-deoxy-L-mannonate) has the “best” kinetic constants, with L-mannonate, L-lyxonate, and D-gulonate dehydrated less efficiently. Crystal structures of the RhamDs from both E. coli K-12 and Salmonella typhimurium LT2 (95% sequence identity) were obtained in the presence of Mg2+; the structure of the RhamD from S. typhimurium was also obtained in the presence of 3-deoxy-L-rhamnonate …

Computation-Facilitated Assignment Of The Function In The Enolase Superfamily: A Regiochemically Distinct Galactarate Dehydratase From Oceanobacillus Iheyensis, John Rakus, Chakrapani Kalyanaraman, Alexander Fedorov, Elena Fedorov, Fiona Mills-Groninger, Rafael Toro, Jeffrey Bonanno, Kevin Bain, J. Sauder, Stephen Burley, Steven Almo, Matthew Jacobson, John Gerlt

John F. Rakus

The structure of an uncharacterized member of the enolase superfamily from Oceanobacillus iheyensis(GI 23100298, IMG locus tag Ob2843, PDB entry 2OQY) was determined by the New York SGX Research Center for Structural Genomics (NYSGXRC). The structure contained two Mg2+ ions located 10.4 A˚ from one another, with one located in the canonical position in the (β/R) 7 β-barrel domain (although the ligand at the end of the fifth β-strand is His, unprecedented in structurally characterized members of the superfamily); the second is located in a novel site within the capping domain. In silico docking of a library of mono- and …

Adding Gas Chromatography-Mass Spectrometry Data To A Melting Point And Thin-Layer Chromatography Laboratory, Adam Azman, Julie Barrett, Megan Darragh, John Esteb, Luanne Mcnulty, Paul Morgan, Stacy O'Reilly, Anne Wilson

John Esteb

The addition of gas chromatography–mass spectrometry (GC–MS) data interpretation to a thin-layer chromatography (TLC) and melting point (mp) laboratory for an introductory organic course is described.

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Efficient Oxidation Of Arylmethylene Compounds Using Nano-Mno2, Baskar Nammalwar, Chelsea Fortenberry, Richard Bunce, Sathish Lageshetty, Kevin Ausman

Kevin D. Ausman

Nano-MnO2 has been developed as an efficient and mild reagent for the high-yield oxidation of arylmethylene compounds to the corresponding aldehydes and ketones as well as benzylic ethers to esters. The reagent is conveniently prepared and shows reactivity superior to synthetic (Attenburrow) MnO2 and commercial MnO2 under both microwave and conventional conditions. Typical reactions are performed using 25 wt % of nano-MnO2 relative to the substrate, and the reagent can be recycled up to six times without significant loss of activity. The observed conversions correlate well with surface-water content in the different MnO2 samples, as determined by thermogravimetric analysis.

The Synthesis And Biological Evaluation Of Tamandarin B Analogs, Kenneth Lassen

Kenneth Lassen

The tamandarin and didemnins are a class of cyclodepsipeptides that have shown a wide range of biological activity. The didemnins have demonstrated antitumor, antiviral and immunosuppressive activity at low nano- and femtomolar levels. Didemnin B was the first marine natural product to enter clinical trials in humans in the United States. The structures of tamandarins A and B were reported in 2000 and possess almost identical structure and biological activity to didemnin B. These compounds have shown impressive biological activity and some progress has been made in establishing structure-activity relationships. However, their molecular mechanism of action is still unclear. The …

Environmentally Friendly Organic Synthesis Using Bismuth(Iii) Compounds, Ram Mohan, Scott Krabbe

Ram S. Mohan

Abstract With increasing environmental concerns, the need for environmentally friendly organic synthesis has gained increased importance. In this regard, bismuth (III) compounds are especially attractive as “green” reagents and catalysts for organic synthesis. Bismuth(III) compounds are remarkably nontoxic, relatively air and moisture stable, and easy to handle. The contributions from our laboratory in the last 5 years in the field of applications of bismuth(III) compounds as catalysts are presented.

Applications Of Bismuth(Iii) Compounds In Organic Synthesis, Ram Mohan, Jason Bothwell, Scott Krabbe

Ram S. Mohan

This review article summarizes the applications of bismuth(III) compounds in organic synthesis since 2002. Although there are an increasing number of reports on applications of bismuth(III) salts in polymerization reactions, and their importance is acknowledged, they are not included in this review. This review is largely organized by the reaction type although some reactions can clearly be placed in multiple sections. While every effort has been made to include all relevant reports in this field, any omission is inadvertent and we apologize in advance for the same (358 references).

Kinetic And Mechanistic Studies Of The Deuterium Exchange In Classical Keto−Enol Tautomeric Equilibrium Reactions, Michael Nichols, Mark Waner

Mark J. Waner

An extension of the classic keto−enol tautomerization of β-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the α-methylene carbon when dissolved in methanol-d4. The extent of deuteration may be monitored via NMR spectroscopy as a function of time. A mechanism for deuterium exchange is presented and shown to be consistent with a consecutive first-order process. The data for acetylacetone are consistent with steady-state kinetics, whereas those of ethyl acetoacetate illustrate nonsteady-state behavior, offering an accessible example where students might collect and analyze real …

Technology For The Organic Chemist: Three Exploratory Modules, John Esteb, Luanne Mcnulty, John Magers, Paul Morgan, Anne Wilson

John Esteb

The ability to use computer-based technology is an essential skill set for students majoring in chemistry. This exercise details the introduction of appropriate uses for this technology in the organic chemistry series. The incorporation of chemically appropriate online resources (module 1), scientific databases (module 2), and the use of a chemical drawing program (module 3) are detailed here.

Note: Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users not affiliated with Butler University should contact their local librarian for assistance in locating a copy …

Bismuth(Iii) Triflate Catalyzed Allylation Of Cyclic Acetals And Dithianes Followed By In Situ Derivatization To Generate Highly Functionalized Esters, Ram Mohan, Scott Krabbe, Matthew Spafford

Ram S. Mohan

No abstract provided.

Kinetic And Mechanistic Studies Of The Deuterium Exchange In Classical Keto−Enol Tautomeric Equilibrium Reactions, Michael Nichols, Mark Waner

Michael A Nichols

An extension of the classic keto−enol tautomerization of β-dicarbonyl compounds into a kinetic analysis of deuterium exchange is presented. It is shown that acetylacetone and ethyl acetoacetate undergo nearly complete deuterium exchange of the α-methylene carbon when dissolved in methanol-d4. The extent of deuteration may be monitored via NMR spectroscopy as a function of time. A mechanism for deuterium exchange is presented and shown to be consistent with a consecutive first-order process. The data for acetylacetone are consistent with steady-state kinetics, whereas those of ethyl acetoacetate illustrate nonsteady-state behavior, offering an accessible example where students might collect and analyze real …

The Effect Of Catalyst Of The Reaction Of P-Hydroxybenzaldehyde With Acetic Anhydride: A Discovery-Oriented Green Laboratory Experiment, Ram Mohan, Matthew Huddle, Michael Devore

Ram S. Mohan

No abstract provided.

A Simple Sn2 Reaction For The Undergraduate Organic Laboratory, John Esteb

John Esteb

A simple procedure for the synthesis of n-butyl naphthyl ether is presented. This procedure represents an easy method for the production of an aryl ether by an SN2 reaction, uses ethanol as an environmentally friendly solvent, and does not require the use of a lachrymator. Product isolation is done by pouring the reaction mixture over ice and collecting the solid by suction filtration. Students typically recover from 7–95% of the ether.

Note: Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users not affiliated with …

A Flexible Solvolysis Experiment For The Undergraduate Organic Laboratory, John Esteb, John Magers, Luanne Mcnulty, Paul Morgan, Kathryn Tindell, Anne Wilson

John Esteb

A simple SN1 reaction is presented that uses bromotriphenylmethane and a range of oxygen-based nucleophiles including water and various alcohols. This procedure represents a process that affords easy isolation of solid products. Typical student yields ranged from 17–128% with the average yield of 50%. Students obtained products with a melting point range of 140 to 164 °C. This procedure offers multiple ways to adapt this experiment from a straight solvolysis reaction to a discovery-based experiment that explores the effect of nucleophile (for a more advanced group) or the method of product isolation. Note: Link is to the article in a …

Environmentally Friendly Organic Synthesis Using Bismuth Compounds. Bismuth Trifluoromethanesulfonate-Catalyzed Allylation Of Dioxolanes, Ram Mohan, Matthew Spaffpord, James Christensen, Matthew Huddle, Joshua Lacey

Ram S. Mohan

A bismuth trifluoromethanesulfonate (triflate)-catalyzed (2.0 mol-%) multicomponent reaction involving the allylation of dioxolanes followed by in situ derivatization with anhydrides to generate highly functionalized esters has been developed under solvent-free conditions. Most reagents used to date for allylation of dioxolanes are highly corrosive and are often required in stoichiometric amounts. In contrast, the use of a relatively non-toxic and non-corrosive bismuth(iii)-based catalyst makes this methodology especially attractive for scale-up.

Synthesis Of Homoallyl Ethers Via Allylation Of Acetals And Aldehydes In Ionic Liquids, Ram Mohan, Peter Anzalone

Ram S. Mohan

The TMS triflate catalyzed allylation of acetals to yield homoallyl ethers proceeds smoothly at room temperature in ionic liquids. A one-pot method for the conversion of aldehydes to homoallyl ethers in an ionic liquid has also been developed. This methodology is attractive because it allows allylations to be carried out at room temperature. Ionic liquids offer a convenient replacement for CH₂Cl₂, the commonly used solvent for such reactions.

Projects That Assist With Content In A Traditional Organic Chemistry Course, John Esteb, John Magers, Luanne Mcnulty, Anne Wilson

John Esteb

Projects that engage undergraduate students in content-based courses, such as organic chemistry, must relate to the material and provide useful tools for the divergent needs of the students. There are few examples of these types of projects in the literature. Herein, we describe two projects, the reaction notebook and the end-of-semester synthesis activity. Each project is designed to stimulate student ownership of the material and leads to engagement with the content of the course.

Note: Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users …

Kinetic Deuterium Isotope Effects On The Reactions Of 2-(4-Methoxyphenyl)Oxirane In Water Solutions, Ram Mohan, Victoria Ukachukwu, Dale Whalen

Ram S. Mohan

The rates of reaction of 2-(4-methoxyphenyl)oxirane (4-methoxystyrene oxide), trans-3-deutereo-2-(4-methoxyphenyl)oxirane and 3,3-dideutereo-2-(4-methoxyphenyl)oxirane in water solutions were measured as functions of pH. Kinetic deuterium isotope effects for the reactions of the mono- and di-deuterated (4-methoxyphenyl)oxiranes were determined for both the acid-catalyzed hydrolysis to diols and the pH-independent reactions leading mostly to rearranged aldehyde and involving a 1,2-hydrogen migration. The inverse kinetic deuterium isotopes for acid-catalyzed hydrolyses of the deuterated (4-methoxyphenyl)oxiranes to diols are consistent with rate-limiting epoxide ring opening. The magnitudes of the normal kinetic deuterium isotope effects on the pH-independent reactions of deuterated 4-methoxyphenyloxiranes are significantly smaller than the deuterium …

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

John Esteb

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.

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Solvent-Free Conversion Of Alpha-Naphthaldehyde To 1-Naphthoic Acid And 1-Naphthalenemethanol: Application Of The Cannizzaro Reaction, John Esteb, Keith Gligorich, Stacy O'Reilly, Jeremy Richter

John Esteb

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 …

Cautionary Comments (Author Response), John Esteb, Anne Wilson

John Esteb

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

Note:Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users not affiliated with Butler University should contact their local librarian for assistance in locating a copy of this article.

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

John Esteb

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.

Note:Link is to the article in a subscription database available to users affiliated with Butler University. Appropriate login information will be required for access. Users not affiliated with Butler University should contact their local librarian for assistance in locating a copy of …

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

John Esteb

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.

Note:Link is to the article in a …