Analytical Chemistry Commons^™

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 transition state structures were identified …

Phosphorylation Of Claudin-5 And Occludin By Rho Kinase In Brain Endothelial Cells, Masaru Yamamoto, Servio H. Ramirez, Shinji Sato, Tomomi Kiyota, Ronald Cerny, Kozo Kaibuchi, Yuri Persidsky, Tsuneya Ikezu

Ronald Cerny Publications

Critical to the proper maintenance of blood-brainbarrier (BBB) integrity are the endothelial tight junctions (TJs). Posttranslational modifications of essential endothelial TJ proteins, occludin and claudin-5, contribute and possibly disrupt BBB integrity. Our previous work has shown that Rho kinase (RhoK) activation mediates occludin and claudin-5 phosphorylation resulting in diminished barrier tightness and enhanced monocyte migration across BBB in the setting of human immunodeficiency virus-1 encephalitis (HIVE). To determine whether RhoK can directly phosphorylate TJ proteins, we examined phosphorylation of cytoplasmic domains of recombinant claudin- 5 and occludin by RhoK. We found that RhoK predominately phosphorylated two sites on occludin (T382 …

Phosphorylation Of Muc1 By Met Modulates Interaction With P53 And Mmp1 Expression, Pankaj K. Singh, Michelle E. Behrens, John P. Eggers, Ronald Cerny, Jennifer M. Bailey, Kandavel Shanmugam, Sandra J. Gendler, Eric P. Bennett, Michael A. Hollingsworth

Ronald Cerny Publications

MUC1, a transmembrane mucin, is a key modulator of several signaling pathways that affect oncogenesis, motility, and cell morphology. The interaction of MUC1 cytoplasmic tail (MUC1CT) with signal transducers and its nuclear translocation and subsequent biological responses are believed to be regulated by phosphorylation status, but the precise mechanisms by which this occurs remain poorly defined. We detected a novel association between the Met receptor tyrosine kinase and the MUC1CT. Met catalyzed phosphorylation of tyrosine at YHPM in the MUC1CT. Stimulation of S2-013.MUC1F pancreatic cancer cells with hepatocyte growth factor facilitated nuclear localization of MUC1CT, as determined by real time …

Structure And Biosynthesis Of Heat-Stable Antifungal Factor (Hsaf), A Broad-Spectrum Antimycotic With A Novel Mode Of Action, Fengan Yu, Kathia Zaleta-River, Xiangcheng Zhu, Justin Huffman, Jeffrey C. Millet, Steven D. Harris, Gary Y. Yuen, Xing-Cong Li, Liangcheng Du

Department of Chemistry: Faculty Publications

A screen for antifungal compounds from Lysobacter enzymogenes strain C3, a bacterial biological control agent of fungal diseases, has previously led to the isolation of heat-stable antifungal factor (HSAF). HSAF exhibits inhibitory activities against a wide range of fungal species and shows a novel mode of antifungal action by disrupting the biosynthesis of a distinct group of sphingolipids. We have now determined the chemical structure of HSAF, which is identical to that of dihydromaltophilin, an antifungal metabolite with a unique macrocyclic lactam system containing a tetramic acid moiety and a 5,5,6-tricyclic skeleton. We have also identified the genetic locus responsible …

Corrosion Studies On The Uss Arizona With Application To A Japanese Midget Submarine, Brent M. Wilson, Donald L. Johnson, Hans Vantilburg, Matthew A. Russell, Larry E. Murphy, James D. Carr, Robert J. De Angelis, David L. Conlin

Department of Chemistry: Faculty Publications

The assessment of corrosion on the USS Arizona included the pioneering development of a minimum-impact cost-effective technique to determine the corrosion rate of steel-hulled shipwrecks in seawater. The technique, with potential application worldwide, is illustrated in this paper with the application to a World War II Japanese midget submarine submerged in deep waters off the Oahu, Hawaii, coast.

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 carbamate groups. The thermal …

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.

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.

A Minimum-Impact Method For Measuring Corrosion Rate Of Steel-Hulled Shipwrecks In Seawater, Matthew A. Russell, David L. Conlin, Larry E. Murphy, Donald L. Johnson, Brent M. Wilson, James D. Carr

Department of Chemistry: Faculty Publications

Current research on USS Arizona is focused on a minimum-impact technique for calculating corrosion rate of the battleship’s steel hull by analysing physical and chemical properties of marine encrustation covering the exposed hull. An equation is derived that allows concretion thickness, density, and total iron content to be used to calculate corrosion rate of steel hull plate.

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 studies demonstrate that both the …

Modifications Of Human Βa1/Βa3-Crystallins Include S-Methylation, Glutathiolation, And Truncation, Veniamin N. Lapko, Ronald Cerny, David L. Smith, Jean B. Smith

Ronald Cerny Publications

Disulfide bonding of lens crystallins contributes to the aggregation and insolubilization of these proteins that leads to cataract. A high concentration of reduced glutathione is believed to be key in preventing oxidation of crystallin sulfhydryls to form disulfide bonds. This protective role is decreased in aged lenses because of lower glutathione levels, especially in the nucleus. We recently found that human [1]-crystallins undergo S-methylation at exposed cysteine residues, a reaction that may prevent disulfide bonding. We report here that βA1/A3-crystallins are also methylated at specific cysteine residues and are the most heavily methylated of the human lens crystallins. Among the …

Analysis Of Free Analyte Fractions By Rapid Affinity Chromatography, David S. Hage, William A. Clarke

Department of Chemistry: Faculty Publications

The invention is generally directed toward an analytical method to determine the concentration of the free analyte fraction in a sample. More particularly, the method encompasses applying a sample comprising a free and bound analyte fraction to an affinity column capable of selectively extracting the free fraction in the millisecond time domain. The signal generated by the free fraction is then quantified by standard analytical detection techniques. The concentration of the free fraction may then be determined by comparison of its signal with that of a calibration curve depicting the signal of known concentration of the same analyte.

Investigations Of Supramolecular And Catalytic Properties Of Ppi Dendrimers, Aaron K. Holley

Theses, Dissertations and Capstones

The research reported in this thesis focused on supramolecular and catalytic properties of poly(propylene imine) (PPI) dendrimers. Analytical techniques used in this research included high resolution NMR spectroscopy, as well as UV-vis and fluorescence spectroscopies and scanning electron microscopy. This investigation showed that: (1) PPI dendrimers interact with diacids to form interlock self-assemblies by electrostatic interactions (with an increase in dendrimer generation, smaller diacids are required to form the most efficient self-assembly); (2) PPI/diacid self-assemblies are able to encapsulate fluorescent dyes within the void spaces of the PPI/diacid moieties; (3) PPI-3 can chelate many types of metal cations, and these …

Oligothiophenes And Synthesis Thereof, Andrzej Rajca

Department of Chemistry: Faculty Publications

Novel oligothiophenes and intermediates therefor are disclosed together with a process for synthesizing them. The oligothiophenes are in the form of a helix which contains five-membered rings unsaturated heterocycles that are cross-conjugated and annelated into a helix.

Preliminary X-Ray Diffraction Studies Of The Transcriptional Inhibitory Antibody Fab41.4, Johanna Mazlo, Robyn L. Stanfield, Ian A. Wilson, Steven H. Hinrichs, John J. Stezowski

Department of Chemistry: Faculty Publications

The binding of transcription factor ATF-1 to DNA contributes to gene expression and regulation of cell growth. Antibody Mab41.4, raised against ATF-1, and its derivatives Fab41.4 and scFv41.4 inhibit specific DNA binding in vitro and induce apoptotic death of tumor cells in vivo. Structural studies of Fab41.4 were performed to gain insight into the mechanism of action of this potentially therapeutic antibody. The optimal conditions for crystallization of Fab41.4 were determined. Crystals were needle-like in appearance, displayed C2 space-group symmetry and diffracted to a resolution of 1.6 Å. The unit-cell parameters were determined to be a = 186.64, b = …

Octafluoro-Meso Tetraarylporphyrins And Methods For Making These Compounds, Stephen G. Dimagno

Department of Chemistry: Faculty Publications

The novel compounds of the present invention are f-octafluoro-meso-tetraarylporphyrins of formula (I) and their metallic complexes of formula (II):

B-octafluoro-meso-tetraaryl porphyrins are Synthesized by reacting 3,4-difluoropyrrole with an aromatic aldehyde in the presence of boron trifluoride etherate, followed by oxidation. The difluoropyrrole used in this reaction is pro duced by reacting 3,3,4,4-tetrafluoropyrroline or its corre sponding Salt, 3,3,4,4-tetrafluoropyrrolidinium Salt, with a base Such as potassium tert-butoxide. The metalloporphyrins of the present invention are Synthesized by deprontonating B-octafluoro-meso-tetraarylporphyrin ligands and treating Said ligands with metal ions.

Heavily Fluorinated Sugar Analogs, Stephen G. Dimagno

Department of Chemistry: Faculty Publications

Heavily fluorinated Sugar analogs of formula

wherein R₁ is selected from alkyl, alkenyl, aryl, CH₂OH, -CH₂-O-alkyl, -CH₂-O-aryl, -CH₂OPO₃H, -CH₂-O-carbohydrate, -CH₂-NH-peptide, or -CH₂-O-peptide; wherein R₂ is selected from hydroxy, -O-carbohydrate, -NH-peptide,

wherein R₃ is selected from H, halogen, lower alkyl, lower alkenyl, lower haloalkyl, lower haloalkenyl, amino, mono- or di-lower alkylamino; wherein R₄ is Selected from amino, hydroxy, alkoxy, or halogen; and wherein R₅ is H or amino. The compounds of formula (I) are useful as antiviral and antineoplastic agents …

Method Of Storing Active Zero Valent Zinc Metal, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel Zerovalent Zinc species and an organozinc reagent are disclosed. The Zerovalent Zinc species is directly pro duced by reaction of a reducing agent on a Zinc Salt, preferably Zn(CN). The organozinc regent results from the reaction of the Zerovalent Zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions Schemes.

Method For The Synthesis Of Α-Oxranyl Amino Acids, David B. Berkowitz, Michelle L. Pedersen

Department of Chemistry: Faculty Publications

The present invention is related to a novel class of decar-boxylase enzyme inhibitors consisting of α-oxiranyl amino acids and derivatives thereof and a method of synthesizing Such compounds.

Pyrrolic Compounds, Michael J. Therien, Stephen Dimagno

Department of Chemistry: Faculty Publications

Novel methylpyrroles are provided, as well as processes for their preparation.

Metathesis-Based Synthesis Of Jasmonate And Homojasmonate Lactones, Candidates For Extracellular Quorum Sensing Molecules In Candida Albicans, Su C. Cho, Patrick Dussault, Amber D. Lisec, Ellen C. Jensen, Kenneth W. Nickerson

Department of Chemistry: Faculty Publications

Ring-closing metathesis of jasmonate esters is shown to provide a rapid entry to jasmonate lactones. The lactones were investigated as possible quorum sensing molecules for the fungi Candida albicans. Assays demonstrated no effect on fungal morphology at concentrations up to 96 mM.

Substituted Polythiophenes From Highly Reactive Zinc Reagents, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel Zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly pro duced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)₂. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.

Cross-Coupling Of Organic Compounds Using Cuprous Odide, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Cross-coupling or addition reactions of organic compounds, including acid halides, allylic halides, and C.B-unsaturated carbonyl containing compounds, with organozinc com pounds may be readily and Safely carried out in the presence of cuprous iodide. The use of this catalyst in the coupling reaction provides for the preparation of commercially useful products in the pharmaceutical, agrochemical and other industries.

Α-Vinyllysine And Α-Vinylarginine Are Time-Dependent Inhibitors Of Their Cognate Decarboxylases, David B. Berkowitz, Wan Jin Jahng, Michelle L. Pedersen

Department of Chemistry: Faculty Publications

(±)-α-Vinyllysine and (±)-α-vinylarginine display time-dependent inhibition of L-lysine decarboxylase from B. cadaveris, and L-arginine decarboxylase from E. coli, respectively. A complete Kitz-Wilson analysis has been performed using a modification of the Palcic continuous UV assay for decarboxylase activity.

Synthesis Of Higher Α-Chlorovinyl And Α-Bromovinyl Amino Acids: The Amino Protecting Group Determines The Reaction Course, David B. Berkowitz, Michelle L. Pedersen, Wan Jin Jahng

Department of Chemistry: Faculty Publications

N-Trifluoroacetyl α-vinyl amino esters are smoothly converted to the corresponding α-chlorovinyl or α-bromovinyl amino esters through the agency of phenyselenyl chloride or phenylselenyl bromide, respectively, followed by oxidation and pyrolysis. Exclusively the (E)-extemal halovinyl isomer and the internal halovinyl isomer are observed. The amino protecting group is a critical determinant of the reaction course (alkene addition vs. 5-exo-trig-like cyclization).

Highly Reactive Form Of Copper And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel Zerovalent copper species and an organocopper reagent are disclosed. The Zerovalent copper species is directly produced by reaction of a reducing agent with a combination of copper(I) cyanide or halide and an alkali metal halide salt. The organocopper reagent resulting from the reaction of the zerovalent copper species and an organic compound having one or more stable anionic leaving groups is a stable reagent that will not significantly homocouple and under controlled conditions tolerates the presence of nitrile, epoxide, imine, enone, ketone, ester, allyl and benzyl groups within the organo radical. The reagent can be controlled so that …

Highly Reactive Zerovalent Metals From Metal Cyanides, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Novel zerovalent metal species and organometallic reagents are disclosed. The zerovalent metal species are directly produced by reaction of a reducing agent on a metal cyanide salt. Preferably, the zerovalent metal species are directly produced by reaction of an alkali metal reducing agent with a metal cyanide salt. The organometallic reagent results from the reaction of the zerovalent metal species and an organic compound having one or more stable anionic leaving groups.

Preparations Of Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group in an ethereal, polyethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydro-carbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme conditions.

Preparation Of Doped Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes, such as doped polycarbynes, prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group and, optionally, containing a doping agent, in an ethereal, poly ethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydrocarbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme con ditions.

Highly Reactive Forms Of Zinc And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly produced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)₂. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.