Chemistry Commons^™

Microwave-Induced Bismuth Nitrate-Impregnated Claymediated Novel Dinitration Of 9,10- Dihydrophenanthrene: A Precursor For New Heterocycles, Ram Naresh Yadav, Leonardo Salazar, Amrendra Kumar Singh, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

A facile method for the dinitration of 9, 10-dihydrophenanthrene using domestic microwave-induced bismuth nitrate-impregnated clay is developed.

Discovery And Characterization Of Chemical Compounds That Inhibit The Function Of Aspartyl-Trna Synthetase From Pseudomonas Aeruginosa, Araceli Corona, Stephanie O. Palmer, Regina Zamacona, Benjamin Mendez, Frank B. Dean, James M. Bullard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Pseudomonas aeruginosa, an opportunistic pathogen, is highly susceptible to developing resistance to multiple antibiotics. The gene encoding aspartyl-tRNA synthetase (AspRS) from P. aeruginosa was cloned and the resulting protein characterized. AspRS was kinetically evaluated, and the KM values for aspartic acid, ATP, and tRNA were 170, 495, and 0.5 μM, respectively. AspRS was developed into a screening platform using scintillation proximity assay (SPA) technology and used to screen 1690 chemical compounds, resulting in the identification of two inhibitory compounds, BT02A02 and BT02C05. The minimum inhibitory concentrations (MICs) were determined against nine clinically relevant bacterial strains, including efflux pump …

Synthesis Of Heterocycles Through Beta Lactams Ring Rupture, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Many Beta lactams are widely used as medicines. The 4-membered ring present in the beta lactams is under strain and therefore, it can undergo cleavage reactions to diverse compounds. Chemical manipulation of the resulting products affords numerous molecules of interest. In this perspective, some examples developed at our laboratory are discussed

Expeditious Green Synthesis Of Versatile Organic Compounds By Diverse Methods, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Synthesis of organic compounds requires organic solvents and reagents to promote them. Very often, toxic solvents are used for this purpose. Many organic reactions require molar proportion of reactants and reagents to accomplish the goal. Some reactions require longer reaction times and produce products without control of stereochemistry. Therefore, development of facile and effective organic reactions under environmentally friendly conditions is necessary. In this perspective, several reactions are discussed that are performed by microwave-induced reactions, catalytic procedures, in the absence of any solvents, one-pot method and in water. Important reactions are chosen to investigate the feasibility of conducting these reactions …

Versatile Catalytic Transfer Hydrogenations In Organic Synthesis, Bimal K. Banik, Khaled J. Barakat, Maghar S. Manhas

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Catalytic transfer hydrogenation reactions are extremely useful in organic synthesis. We have investigated numerous reactions with ammonium formate (and other hydrogen gas donor) and 10% Pd/C successfully without using hydrogen gas. The reactions are very fast and produced products with high yields. Reduction of unsaturated groups, hydrogenolysis, reductive bond cleavage, allylic deacetoxylation, and dehalogenation are conducted using this method. In some instances, useful selectivity of reactions is observed. Most of the reactions are investigated with β-lactams as the substrates.

Stereoselectivity Of Phthalimido Β-Lactams Formation: Synthesis Of 3-Amino Β-Lactams Through A Facile Deprotection Reaction, Armando Paniagua, Ram Naresh Yadav, Sunena Chandra, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Synthesis of amino β-lactams is a crucial objective because of the medicinal properties associated with them and the products derived from of them. Stereocontrolled synthesis of phthalimido β-lactams is performed and cis and trans-phthalimido β-lactams are deprotected with ethylene diamine (and other reagents) to amino β-lactams of diverse structures in excellent yield. This reaction is also conducted under solventless conditions to afford identical products.

Key Enzymes In Cancer: Mechanism Of Action And Inhibition With Anticancer Agents, Debasish Bandyopadhyay, Gabriel Lopez, Stephanie Cantu, Samantha Balboa, Annabel Garcia, Christina Silva, Diandra Valdes

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Several enzymes play significant role in different stages of cancer including proliferation, invasion, metastasis and angiogenesis. Mechanism of actions of a few key enzymes along with their inhibitors have been discussed with particular attentation to riboneucleotide reductase, thymidylate synthease, topoisomerase II, interleukins, cell survival proteins and aminopeptidase N.

Identification Of Chemical Compounds That Inhibit The Function Of Histidyl-Trna Synthetase From Pseudomonas Aeruginosa, Yanmei Hu, Stephanie O. Palmer, Sara Robles, Tahyra Resto, Frank Dean, James M. Bullard

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Pseudomonas aeruginosa histidyl-tRNA synthetase (HisRS) was selected as a target for antibiotic drug development. The HisRS protein was overexpressed in Escherichia coli and kinetically evaluated. The KM values for interaction of HisRS with its three substrates, histidine, ATP, and tRNAHis, were 37.6, 298.5, and 1.5 μM, while the turnover numbers were 8.32, 16.8, and 0.57 s-1, respectively. A robust screening assay was developed, and 800 natural products and 890 synthetic compounds were screened for inhibition of activity. Fifteen compounds with inhibitory activity were identified, and the minimum inhibitory concentration (MIC) was determined for each against a panel of nine pathogenic …

Oxidation Of Dibenzothiophene To Dibenzothiophene-Sufone Using A Molybdenum (Vi) Oxide Catalyst: A Kinetic Study Testing Solvent Dependency And Mole Ratio Efficiency, Tomas Trevino Jr.

Theses and Dissertations

Oxidative desulfurization (ODS) is currently a solution to hydrodesulphurization. Currently, industrial usage of hydrodesulphurization (HDS) is the common source for petroleum purification. Unfortunately, HDS comes with environmental and economical ramifications. Due to the problems and potential hazards being presented with HDS, ODS has become a topic of interest in research development. A kinetic study using molybdenum (VI) oxide as a catalyst was used in oxidative desulfurization. Factors such as mole ratio and solvent dependency were tested for efficiency. As activation energy was calculated to show maximum efficiency with respect to temperature and concentration. Gas Chromatography, FT-IR, and Mass Spectroscopy were …

Remediation Of Lead And Copper Ions From Water Solutions Using Transition Metal Sulfides, Jesus M. Cantu Jr.

Theses and Dissertations

Heavy metal contamination in water solutions has been a major concern since many transition metals don’t play a role in any biological function and are actually detrimental to human health. There have been several techniques that have been implemented for the remediation of heavy metal contaminants. For this project, three metal sulfides—Fe7S8, ZnS, TiS 2—were synthesized and studied for their capabilities to remove Pb(II) and Cu(II) from water solutions. Several parameters were investigated to determine the effects of pH, time, temperature, binding capacities, and interfering ions. The room temperature adsorption capacities ranged 6.23–333.3 mg/g for Pb(II) and 1.31–250 mg/g for …

Remediation Of Trivalent And Hexavalent Chromium Ions From Aqueous Solutions Using Titanium Dioxide Polymorphs, Yvette Cantu

Theses and Dissertations

Three titanium dioxide (TiO2) polymorphs were synthesized and used for the removal of chromium (III) and chromium (VI) from aqueous solutions. Various solution parameters were studied to determine the effects of pH, temperature, time, possible interfering ions, and capacities on the binding of Cr(III) and Cr(VI) to all three polymorphs. pH assays determined the optimum pH for the binding of both Cr(III) and Cr(VI) to each polymorph. Adsorption isotherms determined that the adsorption of Cr(III) was non-spontaneous for the three polymorphs with ΔG values ranging from 6.03 to 12.89 kJ/mol. Furthermore, the binding of Cr(VI) to anatase was also non-spontaneous …

Synthesis Of Tetraethyl ((2-Amino-1,4-Phenylene)Bis(Methylene)) Bis(Phosphonate): An Intermediate In The Synthesis Of Amino-Substituted Conjugated Materials, Ariel Ivan Torres Burgueno

Theses and Dissertations

Discussed here are the syntheses of the phosphonate precursors for the Wittig-Horner synthesis of poly-phenylene vinylene (PPV) and distyrylbenzene (DSB) derivatives and their respective distyrylbenzene analogs containing amino moieties. The synthesis of the different compounds was achieved through bromination, Michaelis-Arbuzov reaction, reduction of the nitro group with a commercial cobalt sulfide catalyst and sodium borohydride. Preliminary evidence for the synthesis of amino substituted distyrylbenzene and of nitro/alkoxy substituted poly(p-phenylene vinylene) was obtained. Characterization of the products was performed by 1H-NMR. Preliminary results of the synthesis of a novel amino-substituted distyrylbenzene (DSB) are presented. The luminescence of the new DSB was …

Hydrodesulfurization Of Dibenzothiophene Using Lanthanum Doped Comos2, Carolina Valdes Bracamontes

Theses and Dissertations

Hydrodesulfurization (HDS) is a technique used in petrochemical industry for the removal of sulfur from crude oil. Using dibenzothiophene (DBT) as a target molecule and CoMoS2 catalysts doped with various concentrations of lanthanum were studied for catalytic activity in the removal of DBT from solution. Catalysts were synthesized using ammonium tetrathiomolydate, cobalt chloride and lanthanum nitrate under a solvothermal decomposition in decalin at 350 °C with H2 gas at 160 psi. To evaluate decomposition effects, a second set of catalyst precursors were decomposed in a tube furnace at 450 °C under a constant flow of 10%/90% H2/Ar. Characterizations of the …

Niclosamide Induces Protein Ubiquitination And Inhibits Multiple Pro-Survival Signaling Pathways In The Human Glioblastoma U-87 Mg Cell Line, Benxu Cheng, Liza Doreen Morales, Yonghong Zhang, Shizue Mito, Andrew Tsin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Glioblastoma is the most common and lethal malignant primary brain tumor for which the development of efficacious chemotherapeutic agents remains an urgent need. The anti-helminthic drug niclosamide, which has long been in use to treat tapeworm infections, has recently attracted renewed interest due to its apparent anticancer effects in a variety of in vitro and in vivo cancer models. However, the mechanism(s) of action remains to be elucidated. In the present study, we found that niclosamide induced cell toxicity in human glioblastoma cells corresponding with increased protein ubiquitination, ER stress and autophagy. In addition, niclosamide treatment led to down-regulation of …

Cytidine Deaminase As A Molecular Target In Cancer: An Insight, Claudia A. Almaraz, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Cancer is one of the leading causes of death globally. Although more than 400 varieties of cancer have been reported, based on cell lines, still the actual reason of all types of cancer is not very clear. Several internal and external factors have been identified and the study is ongoing. Up to now about 73 proteins have been identified that are capable to influence directly various phases of cancer including mutation, cell proliferation, invasion, angiogenesis, and metastasis. Cytidine deaminase is one of the important proteins that is responsible for various types of cancer that includes gastric, liver, biliary tract, bladder, …

Biocidal Defeat Agents Produced By Silver-Iodine Nanoenergetic Gas Generators, Ivan Davila

Theses and Dissertations

Nanostructured aluminum (Al), iodine pentoxide (I2O5) nano-rods, and silver oxide (Ag2O) nanoparticles, (Al-I2O5-Ag 2O) were used to compose the ternary thermite composition that serves as a Nanoenergetic Gas Generator (NGG). This composition produces biocidal gases giving the mixture the ability to destroy highly pathogenic microorganisms or bacteria. The dissemination of the biocidal gas in combustion chamber was observed using a high-speed camera. The testing of NGG combustion process against the living Escherichia coli (E.coli) K-12 strain cells, that were cultivated/placed on the sample/chamber surfaces, demonstrated that iodine and silver atoms clouds were deposited to the bacteria surface. The 10/75/15 wt …

Nanostructured Functional Materials For Advanced Three-Dimensional (3d) Solar Cells, Jared Jaksik, H. Justin Moore, Tarek Trad, Okenwa Okoli, M. Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Advancements in dye-sensitized solar cell (DSSC) technology are occurring at an ever-increasing rate, as the development of novel carbon-based materials, the increasing research into new 3D surface morphologies and cell design, and the focus on the development of new sensitizers and electrolytes have allowed many new possibilities for DSSCs. Solar cells that are three-dimensionally structured offer significant advantages over traditional crystalline / semi-crystalline panels in that they can convert incident photons that strike them at large incident angles, can be flexible / used in applications which require non-rigid materials, and can be substantially cheaper to produce than traditional panels, especially …

An Extended Jahn-Teller Hamiltonian For Large-Amplitude Motion: Application To Vibrational Conical Intersections In Ch3sh And Ch3oh, Mahesh B. Dawadi, Bishnu P. Thapaliya, David S. Perry

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

An extended Jahn-Teller Hamiltonian is presented for the case where the (slow) nuclear motion extends far from the symmetry point and may be described approximately as motion on a sphere. Rather than the traditional power series expansion in the displacement from the C3v symmetry point, an expansion in the spherical harmonics is employed. Application is made to the vibrational Jahn-Teller effect in CH3XH, with X = S, O, where the equilibrium CXH angles are 83° and 72°, respectively. In addition to the symmetry-required conical intersection (CI) at the C3v symmetry point, ab initio calculations reveal sets of six symmetry-allowed vibrational …

Stereochemical Preference Toward Oncotarget: Design Synthesis And In Vitro Anticancer Evaluation Of Diastereomeric B-Lactams, Fabian Olazarán-Santibáñez, Debasish Bandyopadhyay, Pilar Carranza-Rosales, Gildardo Rivera, Isias Balderas-Rentería

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Purpose: In the battle against cancer discovery of new and novel chemotherapeutic agent demands extreme obligation. Development of anticancer compounds with higher potency and reduced side-effects is timely and challenging.

Experimental Design: A small series of fourteen diastereomeric β-lactams (seven pairs) were synthesized through multi-step process exploring [2+2] ketene-imine cycloaddition as the key step. Comparative stereochemical preferences were studied through computational docking and validated by in vitro evaluation. β-tubulin was considered as possible molecular target and in vitro anticancer evaluation was conducted against SiHa, B16F10, K562 and Chang cell lines. Caspase-3 activation assay and hematoxylin/eosin staining of the cells were …

Parameterization Of Ar231453: A Potent Agonist Of The Gpr119 Receptor, A Target For Diabetes Treatment, John E. Hamilton

Theses and Dissertations

The first reported potent agonist for the GPR119 receptor, a potential target for the treatment of diabetes, is 2-fluoro-4-methanesulfonyl-phenyl-{6-[4-(3-isopropyl-[1,2,4]oxadiazol-5-yl)-piperidin-1-yl]-5-nitro-pyrimidin-4-yl}-amine (AR231453). The dynamic interactions of AR231453 with GPR119 using molecular dynamics simulation are of great interest. However, parameters for AR231453 that describe the behavior of the molecule in the CHARMM force field have not been determined. The following study produces parameters by creating model fragments and compares the produced parameters to quantum calculations. The produced parameters are then further refined within the Visual Molecular Dynamics (VMD) program’s plugin program, the Force Field Toolkit as well as Gaussian 09 and CHARMM. Molecular …

Formation Of Lifepo4-Pan Submicron Fibers Via Forcespinning ® For Battery Cathode Applications, Ashlee L. Lopez

Theses and Dissertations

LiFePO4/C composite nanofibers were prepared by utilizing Forcespinning® technology and calcination approaches. Polyacrylonitrile (PAN) was dissolved in N, N-dimethylformamide (DMF) to produce the media that allotted nanofiber formation via Forcespinning® and also served as the carbon source. A LiFePO4 solution was synthesized separately in DMF, which served as the precursor. The separately prepared PAN/DMF and LiFePO4/DMF solutions were then mixed at different weight percent’s (wt.%) prior to being subjected to Forcespinning ®. Elemental analysis of the LiFePO4/PAN nanofibers was characterized by energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). The study of the surface morphology was conducted by scanning …

Calmodulin Lobes Facilitate Dimerization And Activation Of Estrogen Receptor-Alpha, Zhigang Li, Yonghong Zhang, Andrew C. Hedman, James B. Ames, David B. Sacks

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Estrogen receptor α (ER-α) is a nuclear hormone receptor that controls selected genes, thereby regulating proliferation and differentiation of target tissues, such as breast. Gene expression controlled by ER-α is modulated by Ca²⁺ via calmodulin (CaM). Here we present the NMR structure of Ca²⁺-CaM bound to two molecules of ER-α (residues 287–305). The two lobes of CaM bind to the same site on two separate ER-α molecules (residues 292, 296, 299, 302, and 303), which explains why CaM binds two molecules of ER-α in a 1:2 complex and stabilizes ER-α dimerization. Exposed glutamate residues in CaM (Glu-11, …

Calmodulin Lobes Facilitate Dimerization And Activation Of Estrogen Receptor-Α, Zhigang Li, Yonghong Zhang, Andrew C. Hedman, James B. Ames, David B. Sacks

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Estrogen receptor α (ER-α) is a nuclear hormone receptor that controls selected genes, thereby regulating proliferation and differentiation of target tissues, such as breast. Gene expression controlled by ER-α is modulated by Ca2+ via calmodulin (CaM). Here we present the NMR structure of Ca2+-CaM bound to two molecules of ER-α (residues 287–305). The two lobes of CaM bind to the same site on two separate ER-α molecules (residues 292, 296, 299, 302, and 303), which explains why CaM binds two molecules of ER-α in a 1:2 complex and stabilizes ER-α dimerization. Exposed glutamate residues in CaM (Glu-11, Glu-14, Glu-84, …

Non-Traditional Examination: A Study To Improve Academic And Research Performance Of Undergraduate Organic Chemistry Students#, Bimal K. Banik, Ram Naresh Yadav, Sunena Chandra

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

An investigation of conducting a presentation examination instead of a classical written examination method on academic and research performance of undergraduate chemistry students was performed at the University of Texas-Pan American. The results suggest that chemistry students do much better in the presentation examination compared to the written examination at the advanced organic chemistry course. But, the performances of the students in the lower level courses are mixed. However, students do much better in research work when presentation examination was conducted.

Carbon Dioxide-Mediated Preparation Of Pyrroles In Water Following Paal Knorr Method, Ram Naresh Yadav, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Carbon dioxide-mediated new reaction of 2,5-hexanedione and primary amino compounds in water-THF produced N-substituted pyrroles in excellent yield. This method for the preparation of pyrroles is novel, simple, and efficient.

Microwave-Induced Paal-Knorr Reaction With Ammonium Chloride: Synthesis Of Pyrroles, Debasish Bandyopadhyay, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

An expeditious microwave-induced synthesis of pyrroles using commercially available 2,5- dimethoxytetrahydrofuran and primary amines in the presence of ammonium chloride has been achieved in excellent yield.

Carbon Dioxide-Mediated Synthesis Of Pyrroles In Water, Ram Naresh Yadav, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

A novel carbon dioxide-mediated synthesis of diverse pyrroles using 2,5- dimethoxytetrahydrofuran and primary amines has been achieved in excellent yield. Despite the importance of pyrroles, no study has been performed using carbon dioxide as a reagent to accomplish Paal-Knorr reaction.

Microwave-Induced Bismuth Triiodide-Catalyzed Facile Synthesis Of Octahydroxanthenes, Ashlee Chavez, Jessica Cruz, Alexdra Munoz, Ram Naresh Yadav, Debasish Bandyopadhyay, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Microwave-induced reaction of 1,3-cyclohexanedione with numerous aldehydes using bismuth iodide is performed successfully toward the synthesis of important octahydroxanthenes. A most probable mechanism is suggested to explain the formation of products.

Ammonium Chloride-Induced Synthesis Of Pyrroles Via Paalknorr Reaction, Debasish Bandyopadhyay, Bimal K. Banik

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Reaction of commercially available 2,5-hexanedione and primary amino compounds in the presence of ammonium chloride produced N-substituted pyrroles in excellent yield. In contrast to other available methods, this current procedure for the preparation of pyrroles is exceedingly simple, efficient, and eco-friendly and therefore, may find numerous applications in this field.

Dihydropyridines As Calcium Channel Blockers: An Overview, Thelma Salazar, Andres Gonzalez, Debasish Bandyopadhyay

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Cardiovascular disease remains one of the leading causes of death in the United States. It is estimated that 1 in every 3 American adults suffer from high blood pressure. Hypertension, a precursor to most cardiovascular diseases, continues to grow at an alarming rate and is seldom managed carefully. Attempts have been made to manage hypertension and reduce the morbidity and mortality of the cardiovascular organ through methods including diets, increased amount of exercise, and medications. Many commercial drugs have been derived from dihydropyridine due to its antihypertensive property. Dihydropyridine derivatives work by acting as calcium channel blockers blocking the intake …