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Hydantoin Derivatives as Anticonvulsants. I. 5-Cyclohexylalkyl-5-(2-Thienyl)Hydantoins
The study herein described represents a continuation of the work on 5-(2-thienyl)-5-substituted hydantoins which has been in progress in the laboratories of the North Texas State College for the past several years. It has for its purpose the study of the effect of lengthening the carbon chain connecting a cyclohexyl radical to 5-(2-thienyl)hydantoin in the 5- position.
Hydantoins as Anticonvulsants. II. 5-Substituted-Amino Derivatives of 5-Phenylhydantoin
This thesis is a study of 5-substituted-amino derivatives of 5-phenylhydantoin and anticonvulsant activity.
Hydantoins as Anticonvulsants. III. 5-Alkoxy- and Aryloxymethyl-5-(2-Thienyl) Hydantoins
It has been shown in the case of a compound synthesized in this laboratory that substitution of the thienyl group for one of the phenyl groups in diphenyl hydantoin produces a compound with less toxicity and somewhat greater activity. It was considered of interest to carry out an analogous substitution in the series of 5-phenyl-5-alkoxymethylhydantions.
Hydantoins as Anticonvulsants. IV. The Synthesis of 5-Substituted-5-(2-Tetrahydropyranyl) Hydantoins
The project discussed in the paper consists of the substitution of another type of heterocycle, 2-tetrahydropyranyl, in position 5 of the hydantoin nucleus.
Hydantoins as Anticonvulsants. IX. 5-Alkylideniminoxy Derivatives of 5-Phenylhydantoin
This thesis describes the synthesis of a series of 5-alkideniminoxy-5-phenylhydantoins for the purpose of studying their anticonvulsant properties.
Hydantoins as Anticonvulsants. VI. 5-Substituted-Alkoxy Derivatives of 5-Phenylhydantoin
No derivatives of 5-phenylhydantoin with an oxygen atom attached directly in the five position of the hydantoin nucleus have been found in the literature. It was therefore considered of interest to synthesize a series of compounds of this type to determine the effect of the change of the position of the oxygen atom on anticonvulsant activity.
Hydantoins as Anticonvulsants. VI. 5-Substituted-Mercapto Derivatives of 5-Phenylhydantoin
This thesis describes the process of synthesizing 5-substituted-mercapto derivatives of hydantoin in which the sulfur of the side chain is attached directly to the hydantoin nucleus.
Hydantoins as Anticonvulsants. VII. 5-Substituted-Aryloxy Derivatives of 5-Phenylhydantoin
This thesis discusses hydantoins as anticonvulsants. VII. 5-Substituted-aryloxy derivatives of 5-phenylhydantoin.
Hydantoins as Anticonvulsants. VIII. 5-Alkylmercapto Derivatives of 3-Methyl-5-Phenylhydantoin
Recent years have seen a rapid increase in the search for new compounds to be employed in the treatment of convulsions associated with epilepsy and related ailments. The properties desired are a higher degree of effectiveness and lower toxicity than those already in use. This thesis describes the effect of methylation of the 5-alkylmercapto-5-phenylhydantoins.
Hydantoins as Anticonvulsants. V. 5-Substituted-Amino Derivatives of 5-Phenylhydantoin
This thesis describes the preparation of 5-substituted-amino derivatives of 5-phenylhydantoin. The hydantoin derivatives are to be tested for anticonvulsant activity by the Pharmacology Department of the Eli Lilly Company of Indianapolis, Indiana.
The Hydrolysis of α-(Benzenesulfonyl)-Acetophenone
In view of the unexpected behavior of α-(benzenesulfonyl)-acetophenone toward hydrolysis and because of the possible physiological importance of its derivatives it was deemed of interest to make a further study of the hydrolysis of this compound. It was decided to study both the acid and basic hydrolysis of this compound. The problem consisted of finding a satisfactory means of analyzing the hydrolysis products, and carrying out the hydrolysis under the different conditions.
Hyperconjugative Interactions in Silylanilines
The purpose of the present work is to study the bonding interactions between the substituents and the ring π system for a series of ortho and para MeₙH₃₋ₙM (M = C or Si, n = 0-3) substituted N,N-dimethylaniline . Both ground and excited-state interactions were studied and their magnitudes determined. The experimental data were then used in conjunction with molecular orbital calculations to differentiate among inductive, hyperconjugative, and d-pπ interactions on the ground and excited states. Overall, the study indicates that d orbital involvement in the interactions of organosilicon substituents with unsaturated systems is much less significant than is generally held. The importance of pₛᵢ⁻π and pₛᵢ⁻π* hyperconjugative interactions between silicon σ* orbitals and π system in producing the effects of silicon substitution on unsaturated systems has become more apparent.
Improvement of Homogeneity and Adhesion of Diamond-Like Carbon Films on Copper Substrates
Electrodeposition method is used to deposit diamond-like carbon (DLC) films on copper substrates via anodic oxidation at low temperature. These films are characterized using Raman spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy. Homogeneity of these films is studied using Raman spectroscopy and scanning electron microscopy. Scotch tape peel tests indicate adherent film on copper substrate. Carbon phase transformation is studied using thermal annealing experiments in conjunction with Raman spectroscopy and scanning electron microscopy. A cathodic electrochemical method is also studied to deposit diamond-like carbon films on copper substrates. However, films deposited by the cathodic route have poor adhesion and quality compared to anodically deposited films. It is also possible to grow diamond phase on copper substrates using acetylene in liquid ammonia via electrodeposition route. An electrochemical method is proposed for boron doping into DLC films.
In vitro Biomedical Application and Photothermal Therapy Evaluation of Gold Complexes and Gold Nanoparticles
Plasmonic photothermal therapy (PPTT) has a rising promise for treating different cancer cells such as lymphoma or stomach cancer. Technique development of PPTT using metallic nanoparticles is developed upon a modification of the irradiation therapy using two major changes: using a less harmful visible amber light (excluding blue light) and using gold-loaded biocompatible nanoparticles. Acrylate nanoparticles were loaded with desired types of gold nanoparticles at different sizes. The gold-loaded gold nanoparticles were conjugated to cancer cells. By selectively delivering the gold nanoparticles into cancer cells, irradiating a harmless amber visible light will achieve thermal ablation of the cancer cells. Based on imaging spectroscopy, flow cytometry, and cell viability assays, results showed reduction of gold-loaded viable cancer cells upon irradiating with amber visible light, no change in the number of cancer cells with irradiating with light only. On the other hand, DNA intercalation of a trinuclear gold(I), [Au(3-CH3,5-COOH)Pz]3 (Au3) is contrasted with the standard organic intercalators ethidium and ellipticine, as investigated computationally. Frontier molecular orbital energies of intercalators and DNA base pairs were determined and found that all intercalators are good electron acceptors with Au3 being the best electron acceptor having the lowest LUMO. DNA base pairs are better electron donors having the lowest HOMO values, and from the intercalators and base pairs' HOMO/LUMO energies, it is evident the intercalators will overlap with the HOMO of DNA stabilizing the intercalators. Interaction energies (kcal/mol) were obtained as a function of distance, r (angstroms). Results show that the theoretical treatment SDD-WB97XD outperforms SDD-LSDA in both adenine-thymine (AT) systems with ethidium and Au3 intercalators. In both guanine-cytosine (GC) and AT pairs, the Au3 has the lowest interaction energies among these common intercalators, suggesting a potential intercalating drug. Experimental DNA intercalation studies were attempted and methods of finding intercalation binding constants were established, showing gold …
The Influence of Selected Non-Bonded Interactions on Vicinal Carbon-Carbon Coupling Constants
The body of information concerning carbon-carbon spin-spin coupling constants now includes a large number of coupling constants, the establishment of a dihedral angular dependence on 3JCC, and the application of 3JCC to conformational analysis. This study adds another dimension to the growing wealth of information associated with 13 C-NMR: the influence of some non-bonded interactions on 3JCC Four types of non-bonded interactions that could influence vicinal carbon-carbon NMR coupling constants were investigated. To facilitate the NMR studies, a variety of 13C-labeled compounds were synthesized.
The Infra-red Absorption Spectrogram of Ethylidene Fluoride
This thesis is a study of the near infra-red absorption spectrum of ethylidene fluoride.
Infrared Studies of Anions of Barbituric Acids
As long ago as 1881, it was realized that a functional group of atoms in a molecule would cause an absorption band to appear at a particular frequency in the infrared spectrum of the molecule. In more recent years, the concept of characteristic group frequencies has become firmly established and has resulted in the present widespread use of infrared spectroscopy. There appear to have been relatively few studies of infrared absorption of organic acids as compared with their salts.
Infrared Studies of Anions of Organic Acids
The present work is a part of a systematic investigation of the frequency shifts in infrared absorption produced by changing to the anions carbonyl containing acidic compounds.
Infrared Studies of Group VIB metal Carbonyl Derivatives
With three different proposals for the bonding in metal carbonyls, it was decided to look into the situation more thoroughly in order to see what other evidence was available to support or refute any of these ideas. It became obvious that a definite contradiction existed between the kinetic evidence of various metal carbonyls, and the concept of MC bond strengths as predicted by Cotton's theory.
An Infrared Study of some Ω-Phenyl and Ω-Benzoyl Alkanoic Acids
There is no available information in the literature on interaction between carboxyl hydrogen and ω-phenyl groups. Consequently, it was of interest to seek such interactions. Some form of interaction is evident from the study of the spectra of some phenylalkanoic acids and benzoyalkanoic acids.
Inhibitors of Dihydrofolate Reductase, 8-Oxapteridines
The biological activities of some homeosterically related analogs of dihydrofolic acid have been examined involving pyrimido[4,5-b][l,4]oxazine (8-oxapteridine) derivatives. It is anticipated that these compounds might interfere with the essential intermediary metabolic functions of the vitamin and thus serve as potential chemotherapeutic agents. Preliminary toxicity studies in microbial assay systems were disappointing; however, inhibitory effects were demonstrated in cell free enzyme systems. A comparison of the structure/activity relationships was determined using two folic acid coenzyme systems, dihydrofolate reductase and thymidylate synthetase. The 2-amino-4-hydroxy-6-(substituted)-8-oxapteridines were generally more effective inhibitors than the corresponding 2,4-diamino analogs. The relative biological activity of a series of 2-amino-4-hydroxy-6-ω-phenylalkyl derivatives were examined, and the most active derivative was the 6-phenylethyl analog which appears to function as a mixed-type inhibitor involving partially competitive and partially non-competitive inhibition.
Instrumental Development and Implementation of Portable Membrane Inlet Mass Spectrometry for Homeland Security and Environmental Applications
A rapidly growing topic of great interest is the adaptation of benchtop analytical instrumentation for use in outdoor harsh environments. Some of the areas that stand to benefit from field instrumentation development include government agencies involved with the preservation of the environment and institutions responsible for the safety of the general public. Detection systems are at the forefront of the miniaturization movement as the interest in analyte identification and quantitation appears to only be accessible through the use of analytical instrumentation. Mass spectrometry is a distinguished analytical technique known for its ability to detect the mass-to-charge (m/z) ratios of gas-phase ions of interest. Although these systems have been routinely limited to research lab-based analysis, there has been considerable development of miniaturized and portable mass spectrometry systems. Membrane Inlet Mass Spectrometry (MIMS) is becoming a common method of sample introduction that is subject to significant development. MIMS allows for minimal sample preparation, continuous sampling, and excludes complicated analyte introduction techniques. Sampling is accomplished using a semipermeable membrane that allows selective analyte passage into the vacuum of the mass spectrometer. MIMS is becoming the preeminent choice of homeland security and environmental monitoring applications with increasing opportunities for the future development of specialized systems. The steadfast development of miniaturized mass spectrometry systems with efficient operation capabilities for a variety of applications gives promise to the further development of MIMS technology as well as other analytical instrumentation.
Interaction of learning approach with concept integration and achievement in a large guided inquiry organic class.
A study was conducted to investigate the relationship of students' concept integration and achievement with time spent within a topic and across related topics in a large first semester guided inquiry organic chemistry class. Achievement was based on evidence of algorithmic problem solving; and concept integration was based on demonstrated performance explaining, applying, and relating concepts to each other. Twelve individual assessments were made of both variables over three related topics - acid/base, nucleophilic substitution and electrophilic addition reactions. Measurements included written, free response and ordered multiple answer questions using a classroom response system. Results demonstrated that students can solve problems without conceptual understanding. A second study was conducted to compare the students' learning approach at the beginning and end of the course. Students were scored on their preferences for a deep, strategic, or surface approach to learning based on their responses to a pre and post survey. Results suggest that students significantly decreased their preference for a surface approach during the semester. Analysis of the data collected was performed to determine the relationship between students' learning approach and their concept integration and achievement in this class. Results show a correlation between a deep approach and concept integration and a strong negative correlation between a surface approach and concept integration.
Interactions of Clean and Sulfur-modified Reactive Metal Surfaces with Aqueous Vapor and Liquid Environments : A Combined Ultra-high Vacuum/electrochemistry Study
The focus of this research is to explore the molecular-level interactions between reactive metal surfaces and aqueous environments by combined ultra-high vacuum/electrochemistry (UHV-EC) methodology. The objectives of this work are to understand (1) the effects of sulfate ions on the passivity of metal oxide/hydroxide surface layer, (2) the effects of sulfur-modification on the evolution of metal oxide/hydroxide surface layer, and (3) the effects of sulfur adsorbate on cation adsorption at metal surfaces.
Interfacial Studies of Bimetallic Corrosion in Copper/Ruthenium Systems and Silicon Surface Modification with Organic and Organometallic Chemistry
To form Cu interconnects, dual-damascene techniques like chemical mechanical planarization (CMP) and post-CMP became inevitable for removing the "overburden" Cu and for planarizing the wafer surface. During the CMP processing, Cu interconnects and barrier metal layers experience different electrochemical interactions depending on the slurry composition, pH, and ohmic contact with adjacent metal layers that would set corrosion process. Ruthenium as a replacement of existing diffusion barrier layer will require extensive investigation to eliminate or control the corrosion process during CMP and post CMP. Bimetallic corrosion process was investigated in the ammonium citrate (a complexing agent of Cu in CMP solutions) using micro test patterns and potentiodynamic measurements. The enhanced bimetallic corrosion of copper observed is due to noble behavior of the ruthenium metal. Cu formed Cu(II)-amine and Cu(II)-citrate complexes in alkaline and acidic solutions and a corrosion mechanism has been proposed. The currently used metallization process (PVD, CVD and ALD) require ultra-high vacuum and are expensive. A novel method of Si surface metallization process is discussed that can be achieved at room temperature and does not require ultra-high vacuum. Ruthenation of Si surface through strong Si-Ru covalent bond formation is demonstrated using different ruthenium carbonyl compounds. RBS analysis accounted for monolayer to sub-monolayer coverage of Si surface. Interaction of other metal carbonyl (like Fe, Re, and Rh) is also discussed. The silicon (111) surface modifications with vinyl terminated organic compounds were investigated to form self-assembled monolayers (SAMs) and there after these surfaces were further functionalized. Acrylonitrile and vinylbenzophenone were employed for these studies. Ketone group of vinylbenzophenone anchored to Si surface demonstrated reactivity with reducing and oxidizing agents.
Intermediates for Paracyclophane Synthesis
It is proposed in this thesis that the imperfect systems of Cram and of Schubert be combined with some modifications.
Intramolecular 2+2 Cycloadditions of Ketenes
The objective of this study was to explore intramolecular ketene cycloadditions with the anticipated results of developing new synthetic methodology for the synthesis of polycyclic compounds difficult to obtain by other procedures. (o-Alkenylphenoxy)ketenes were initially selected for this study because these ketenes provided a favorable proximity for the intramolecular [2+2] cycloaddition reactions. The difunctional precursors, (o-alkenylphenoxy)- acetic acids, were readily prepared from o-alkenylphenols and ∝-halocarboxylic acids and were converted to the corresponding acid chlorides by reaction with oxalyl chloride. The acid chlorides were dehydrochlorinated to the corresponding (o-alkenylphenoxy)ketenes by treatment with triethylamine. The ketenes undergo a facile intramolecular [2+2] cycloaddition to give polycyclic eye 1obutanones. The (o-vinylphenoxy)ketenes are clearly more reactive than the (o-allylphenoxy)ketenes and provide much better yields of the cycloaddition products because of electronic effects in the transition state in the cycloaddition process. The intramolecular [2+2] cycloadditions of keteniminium salts were included in this study as a more electrophilic alternative to ketenes that will react with less nucleophilic carbon-carbon double bonds. However, the use of keteniminium salts instead of ketenes in Intramolecular cycloadditions does have some limitations. The synthesis of benzofurans via the intramolecular [2+2] cycloadditions of (o-acylphenoxy)ketenes was accomplished. The initially formed ß-lactone cycloaddition products spontaneously underwent decarboxylation to the benzofurans. The aromaticity of the benzofurans is apparently a very strong driving force for the cycloaddition. During the course of this study, two new synthetic methods were discovered which in many instances represent a significant Improvement over existing methods. The Wittig Reactions of ketoacids without protecting the carboxyl groups provide a reliable source of the precursor unsaturated acids needed for intramolecular ketene-olefin cycloadditions. Also, the one-pot preparation of intramolecular ketene cycloaddition products from the carboxylic acid via the tosylate represents a new synthetic method. This procedure eliminates the acid halide preparation, isolation and purification step, thereby significantly …
Intramolecular [2+2] Cycloadditions of Phenoxyketenes and Intermolecular [2+2] Cycloadditions of Aminoketenes
One objective of this study was to explore the intramolecular [2+2] cycloadditions of phenoxyketenes to carbonyl groups with isoflavones and benzofurans as target compounds. The other objective was to investigate the eyeloaddition reactions of rarely studied aminoketenes. The conversion of 2-(carboxyalkoxy)benzils to the corresponding phenoxyketenes leads to an intramolecular [2+2] cycloaddition to ultimately yield isoflavones and/or 3-aroylbenzofurans. The product distributions are dependent upon the substitution pattern in the original benzil acids. The initial cycloaddition products, β-lactones, are isolated in some instances while some β-lactones spontaneously underwent decarboxylation and could not be isolated. The ketene intermediate was demonstrated in the intramolecular reaction of benzil acids or ketoacids with sodium acetate and acetic anhydride. It is suggested that sodium acetate and acetic anhydride could serve as a source for the generation of ketenes directly from certain organic acids. The treatment of ketoacids with acetic anhydride and sodium acetate provides a simpler procedure to prepare benzofurans than going through the acid chloride with subsequent triethylamine dehydrochlorination to give the ketenes. N-Ary1-N-alkylaminoketenes were prepared for the first time from the corresponding glycine derivatives by using p-toluenesulfonyl chloride and triethylamine. These aminoketenes underwent in situ cycloadditions with cyclopentadiene, cycloheptene and cyclooctenes to yield only the endo -bicyclobutanones. The cycloheptene and cyclooctene cycloaddition products underwent dehydrogenation under the reaction conditions to yield bicycloenamines. A mechanism is proposed for this dehydrogenation involving a radical cation of the arylalkylamine. (N-Phenyl-N-methyl) aminomethylketene was also prepared and found to undergo an intramolecular Friedel-Crafts type acylation to yield an indole derivative when prepared by the acetic anhydride, sodium acetate method. The in situ cycloaddition of N-aryl-N-alkyl aminoketenes with various imines was found to form predominately cis-3-amino-2-azetidinones. A mechanism involving a dipolar intermediate is provided whereby the structure of the intermediate is determined by both electronic and steric effects. The stereochemistry of …
Investigating Molecular Structures: Rapidly Examining Molecular Fingerprints Through Fast Passage Broadband Fourier Transform Microwave Spectroscopy
Microwave spectroscopy is a gas phase technique typically geared toward measuring the rotational transitions of Molecules. The information contained in this type of spectroscopy pertains to a molecules structure, both geometric and electronic, which give insight into a molecule's chemistry. Typically this type of spectroscopy is high resolution, but narrowband ≤1 MHz in frequency. This is achieved by tuning a cavity, exciting a molecule with electromagnetic radiation in the microwave region, turning the electromagnetic radiation o, and measuring a signal from the molecular relaxation in the form of a free induction decay (FID). The FID is then Fourier transformed to give a frequency of the transition. "Fast passage" is defined as a sweeping of frequencies through a transition at a time much shorter (≤10 s) than the molecular relaxation (≈100 s). Recent advancements in technology have allowed for the creation of these fast frequency sweeps, known as "chirps", which allow for broadband capabilities. This work presents the design, construction, and implementation of one such novel, high-resolution microwave spectrometer with broadband capabilities. The manuscript also provides the theory, technique, and motivations behind building of such an instrument. In this manuscript it is demonstrated that, although a gas phase technique, solids, liquids, and transient species may be studied with the spectrometer with high sensitivity, making it a viable option for many molecules wanting to be rotationally studied. The spectrometer has a relative correct intensity feature that, when coupled with theory, may ease the difficulty in transition assignment and facilitate dynamic chemical studies of the experiment. Molecules studied on this spectrometer have, in turn, been analyzed and assigned using common rotational spectroscopic analysis. Detailed theory on the analysis of these molecules has been provided. Structural parameters such as rotational constants and centrifugal distortion constants have been determined and reported for most molecules in …
Investigation Into the Causes for the Loss of Resolution in an Ion Chromatograpy Resin
Four mechanisms were considered as possible causes of the loss in resolution for a Dionex CG2 ion chromatography resin: 1) presence of inorganic ions strongly bound to the active sites; 2) adsorption of organic species; 3) physical alterations; and 4) chemical alterations. The instrumental analyses used to gather data were ICP, FT-IR, SEM, solid C-13 NMR and IC. Based on the results, no metal ions are bound to the resin, no organic species are held onto the resin, and no physical change was observable. The cause for the loss of resolution is a strong reduction in the number of active sites in the resin as confirmed by elemental analysis for the sulfur in the sulfonic acid present in the active sites.
An Investigation into the Micromechanical and Corrosion Properties of Additively Manufactured Stainless Steel 316L
In this thesis, micro-mechanical properties and corrosion resistance of laser powder bed fusion (L-PBF) processed additive manufactured (AM) 316L stainless steel parts were investigated for different combinations of processing parameters. Various laser powers were employed for the fabrication of all AM 316L stainless steel parts. Nanoindentation, areal roughness, and electron backscattered diffraction (EBSD) characterization were used to characterize the surface of the AM samples prior to corrosion testing. Open circuit potential (OCP), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization tests were done to compare AM L-PBF 316L stainless steels with different processing parameters. Overall, it was observed that the AM part having a 56.67 J/mm3 volumetric energy density (VED) exhibits the best micro-mechanical characteristics. This sample also had the lowest areal surface roughness and smallest grain size. Consequently, this parameter combination had better corrosion resistance compared to the other AM processed 316L parts. The results are useful in process calibration when fabricating for corrosion resistance applications and provide insights into the relationship among nano-mechanical, crystallography, and long-term corrosion performance.
Investigation of Copper-Natural Ligand Complexes by RP-HPLC Photodiode Array UV-VIS and Fluorescence Detection
In this study, reversed phase HPLC with dual UV photodiode (PDA) and fluorescence (FL) detection were used to investigate copper complexes with fulvic, caffeic, vanillic, salicylic, and adipic acids. Application of the RE method provided valuable information on the retention behavior and spectral characteristics of FA and model compounds. Even though the method was only applicable to VA, the use of the PDA detector allowed the UV-V is scanning of the separated peaks. This allowed the comparison between the UV-Vis spectra of uncomplexed species. The overall results provide an experimental framework for validation of the proposed Cu-humate interaction models.
Investigation of Copper Out-Plating Mechanism on Silicon Wafer Surface
As the miniaturization keeps decreasing in semiconductor device fabrication, metal contamination on silicon surfaces becomes critical. An investigation of the fundamental mechanism of metal contamination process on silicon surface is therefore important. Kinetics and thermodynamics of the copper out-plating process on silicon surfaces in diluted HF solutions are both evaluated by several analytical methods.
Investigation of Ionic Liquid Phases for Chromatographic Separation of Fentanyl Analogues
Opioid abuse and in particular fentanyl, a synthetic opioid, has been of concern in the last decade. Fentanyl is an illicit drug of concern to due to its prevalence and potency. Research to date has focused on supporting law enforcement by developing methods suitable for chemical profiling and identifying fentanyl from various matrices. However, methods geared towards analysis of fentanyl isomeric analogues are rare. Analysis of isomers is challenging due to similar mass spectral fragmentation patterns and exhibiting co-elution using common gas chromatographic columns. Developing methods to use in forensic labs utilizing already available equipment will advance current capabilities in the detection of fentanyl compounds. Thus, investigation into alternative stationary phases and development of special gas-liquid chromatographic (GLC) based methods for isomeric fentanyl analogues has been done. Several studies were done to investigate the use of ionic liquid chromatographic phases in analyzing fentanyl analogues. The first study focused on investigating the thermal stability of ionic liquids to identify those suitable to withstand the high oven temperatures that was needed to elute fentanyl analogues in gas chromatography. Total synchronous fluorescence spectroscopy and differential scanning calorimetry were demonstrated to be sensitive enough to detect the decomposition products of ionic liquids. In the second study, gas chromatographic analysis was done on fentanyl analogues using an ionic liquid stationary phase as well as two commonly used stationary phases for comparison purposes. The applicability of the developed methods was tested using standard fentanyl analogue samples as well as in-house synthesized samples on all three columns. In the third study, quantitative structure property relationship equations were developed to predict the retention time of fentanyl analogues on two of the gas chromatographic stationary phases used in the second study.
Investigation of Structure and Properties of Low Temperature Deposited Diamond-Like Carbon Films
Electrodeposition is a novel method for fabrication of diamond-like carbon (DLC) films on metal substrates. In this work, DLC was electrochemically deposited on different substrates based on an anodic oxidation cyclization of acetylene in liquid ammonia. Successfully anodic deposition was carried out for DLC onto nickel substrate at temperatures below -40°C. Comparative studies were performed on a series of different carbon sources (acetylene, sodium acetylide, and a mixture of acetylene and sodium acetylide). The films were characterized using a variety of methods including Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), XPS valence band spectra, and/or scanning electron microscopy (SEM). Raman spectroscopy is used as a bench mark technique to verify the presence of deposited DLC films, to access the films homogeneities, and to provide the ratio of the different carbon phases, mainly disordered graphite (D) and graphite (G) phases in the films. A combination of the Raman with FTIR and valence band spectra analysis allowed the distinction between hydrogenated DLC and unhydrogenated DLC films. Three different kinds of DLC [(1) hydrogenated DLC (a-C:H); (2) tetrahedral hydrogenated DLC (ta-C:H); and (3) graphitic-like DLC] were deposited depending upon the deposition conditions and substrates. Temperature and current density are the most important parameters to govern the quality of the deposited films, where adding of acetylide into the electrolyte led to films with a higher degree of graphitic phases. The proposed mechanism for acetylene anodic oxidation does not involve direct electron transfer but electrochemical cyclization of acetylene radical cations and hydrogen abstraction at the termination steps. Sodium acetylide, however, dissociates to an acetylenic ion, C2H-, in liquid ammonia. The electrochemistry heterogeneity also leads to island and two-dimensional (2D) nucleation growth of DLC films. Different bond formations of metal to carbon and different chemisorptions of acetylene on metal play important roles …
Investigation of Substituent Effects of 2-Substituted Silaethylenes
This investigation is concerned with determining whether a carbon substituent or a silicon substituent on the carbon terminus of a silicon-carbon double bond has a more stabilizing effect. Two different 2-substituted silaethylenes were generated at the same time by pyrolyzing 1, 1-dimethyl-2-neopentyl-4- (dimethylalkoxysilyl) silacyclobutanes in a nitrogen flow system. The results of these pyrolyses, both neat and in the presence of a trapping reagent, show that the silaethylene with a silicon substituent on the carbon terminus was favored approximately two to one over the silaethylene with a carbon substituent. This datum, along with other observations and hypotheses discussed, leads to the suggestion that the silicon substituenton the carbon terminus of the silaethylene bond has a more stabilizing effect than the carbon substituent.
Investigation of the Possible Application of High and Low Frequency Conductance Measurements to the Analysis of Poly-Component Systems
The immediate goal of this thesis was the analysis of a three-component system whose major component was water. This analysis was to be the result of a procedure which could be readily extended to more complex systems.
Investigation of the Pressure Dependence of SO3 Formation
The kinetics of the pressure dependent O + SO2 + Ar reaction have been investigated using laser photolysis resonance fluorescence at temperatures of 289 K, 399 K, 581 K, 699 K, 842 K and 1040 K and at pressures from 30-665 torr. Falloff was observed for the first time in the pressure dependence. Application of Lindemann theory yielded an Arrhenius expression of k(T) = 3.3 x 10-32exp(-992/T) cm6 molecule-1 s-1 for the low pressure limit and k(T) = 8.47 x 10-14exp(-468/T) cm3 molecule-1 s-1 for the high pressure limit at temperatures between 289 and 842 K. The reaction is unusual as it possesses a positive activation energy at low temperature, yet at higher temperatures the activation energy is negative, illustrating a reaction barrier.
Investigation of Ultratrace Metallic and Organic Contaminants in Semiconductor Processing Environments
Detection of ultratrace levels of metallic ion impurities in hydrofluoric acid solutions and alkaline hydrogen peroxide solution was demonstrated using a silicon-based sensing electrode. The sensor's operation principle is based on direct measurements of the silicon open-circuit potential shift generated by the interaction between metallic ions and the silicon-based sensing surface. The new sensor can have practical applications in the on-line monitoring of microelectronic chemical processing. The detection of Ag+ content in KODAK waste water was carried out successfully by this novel sensor. Trace levels of organic impurities in the hydrofluoric acid solutions and in the cleanroom air were characterized by multiple internal reflection infrared spectroscopy (MIRIS) using an organics probe prepared directly from a regular silicon wafer.
Investigations of Thermochemistry and the Kinetics of H Atom Radical Reactions
The thermochemistry of several species, and the kinetics of various H atom radical reactions relevant to atmospheric and combustion chemistry were investigated using ab initio theoretical techniques and the flash photolysis / resonance fluorescence technique. Using ab initio quantum mechanical calculations up to the G3 level of theory, the C-H bond strengths of several alkanes were calculated. The bond strengths were calculated using two working reactions. From the results, it is apparent that the bond strengths decrease as methyl groups are added to the central carbon. The results are in good agreement with recent experimental halogenation kinetic studies. Hydrogen bond strengths with sulfur and oxygen were studied via CCSD(T) theory, together with extrapolation to the complete basis set limit. The results for the bond dissociation energies (ground state at 0 K, units: kJ mol-1) are: S-H = 349.9, S-D = 354.7, HS-H = 376.2, DS-D = 383.4, and HO-H = 492.6. These data compare well with experimental literature. The rate constants for the isotopic reactions of H + H2S, D + H2S, H + D2S, and D + D2S are studied at the QCISD(T)/6-311+G(3df,2p) level of theory. The contributions of the exchange reaction versus abstraction are examined through transition state theory. The energy of NS was computed via CCSD(T) theory, together with extrapolation to the complete basis set limit. The results were employed with three working reactions to find ΔfH0(NS) = 277.3 ± 2 kJ mol-1 and ΔfH298(NS) = 278.0 ± 2 kJ mol-1. This thermochemistry is consistent with, but much more precise than, earlier literature values. A kinetic study of the reaction of H + CH2CCl2 was conducted over the temperature range of 298 - 680 K. The reaction was found to be pressure dependent and results of the rate constants and their interpretation via unimolecular rate theory are …
Ion Chromatography of Soluble Cr(III) and Cr(VI)
Ion chromatography coupled with a conductivity detector was used to investigate the analysis of Cr(III) and Cr(VI) in aqueous samples. An IC methodology for Cr(III) was developed using a cation column and an eluent containing tartaric acid, ethylenediamine, and acetonitrile at pH 2.9. The detection limit of this method can reach 0.1 ppm level with good precision. Several operational parameters were evaluated during the regular use of the method. Comparison of the IC method with AA method showed good agreement between the two methods. The anion exchange column was used for Cr(VI) determination. The best results were obtained with an eluent containing sodium gluconate, borate buffer, glycerin, and acetonitrile. The retention time for the Cr207 2 - sample was 11 min. and the calibration curve was linear between 1.0 and 100 ppm.
Isolation and Characterization of Proteus vulgaris Methylglyoxal Synthetase
Methylglyoxal synthetase, which catalyzes the formation of methylglyoxal and inorganic phosphate from dihydroxyacetone phosphate, was found in extracts of Proteus vulgaris. An efficient purification procedure utilizing ion exchange column chromatography and isoelectric focusing has been developed. Homogeneity of the enzyme preparation was confirmed by polyacrylamide gel electrophoresis and rechromatography.Two components of methylglyoxal synthetase were obtained upon isoelectric focusing. A comparison of the chemical and physical properties of the two components was carried out. The enzyme is a dimer. In the presence of inorganic phosphate, the hyperbolic saturation kinetics with dihydroxyacetone phosphate are shifted to sigmoidal.
Isolation and Characterization of Yeast NAD⁺ Kinase
The cytoplasmic enzyme, NAD⁺ kinase (ATP: NAD⁺ 2-phosphotransferase, [E.C. 2.7.1.23}) has been characterized and purified from yeast. A continuous fluorescence assay was developed. A purification procedure was developed utilizing NAD⁺-Agarose affinity column chromatography.
The Isolation and Chemical Study of Compounds Produced by a Strain of Penicillium Notatum
It is the purpose of this paper to present data on the isolation and study of the chemical nature of compounds produced by this strain of mold which resembles Penicillium notatum nestling.
Isolation and Partial Characterization of Lecithin Cholesterol Acyltransferase and High Density Lipoprotein from Hog Plasma
Lecithin:cholesterol acyltransferase (LCAT) was purified 30,000-fold from hog plasma in a homogeneous state as indicated by polyacrylamide gel electrophoresis. The purified enzyme had an apparent molecular weight of 66,000 and was found to contain about 21.4 percent (w/w) carbohydrate. The properties of hog LCAT including amino acid composition were compared with human LCAT. High density lipoprotein (HDL) was isolated from the hog plasma by an immunoaffinity column chromatography. The isolated HDL showed nearly identical lipid-protein composition although it contained additional protein components when it was compared to HDL isolated by a traditional method involving ultracentrifugation.
Isolation, Physical and Chemical Characterization of Lecithin:Cholesterol Acyltransferase from Human Plasma
The physiological role of LCAT has been the subject of a number of recent articles (Glomset, 1979; Nilsson-Ehle et al., 1980). According to most current theories, the enzyme functions in combination with high-density lipoproteins in the reverse cholesterol transport pathway which presumably returns peripheral cholesterol to the liver where cholesterol catabolism takes place. Despite the exciting potential for studies on the catalytic function and the nature of the enzyme-substrate complex, the mechanism of action of LCAT remains largely unexplored. The relatively slow progress in the elucidation of the LCAT reaction mechanism is likely to be due to the difficulties in the isolation of the enzyme in sufficient quantities. Consequently, considerably less is known about the physical and chemical properties of the enzyme. Therefore, the first objective of this investigation was to isolate and purify sufficient amount of enzyme for subsequent characterization studies. The second objective of this investigation was to characterize the physical properties of the enzyme by techniques including analytical ultracentrifugation, ultraviolet spectroscopy, and circular dichroism and fluorescence spectroscopy. The third objective of this investigation was to characterize the chemical properties of the enzyme which deals with the amino acid and carbohydrate composition and with some basic structural features that are related to the chemical composition of LCAT.
Isomerization Reactions in Organosilicon Chemistry
Dimethylsilene, generated from the thermal gas phase reaction of 1,1-dimethyl-1-silacyclobutane, reacts with alkynes to produce silacyclobutenes or acyclic silanes. The temperature dependence of the product ratios have been determined and the relative reactivities of three different alkynes toward the 1,1-dimethylsilene has been determined. 1-Hydrido-1-methylsilene has been generated by gas phase thermal decomposition from three different precursors. Trapping studies with butadiene and trimethylsilane lead to products expected from dimethylsilylene. The most plausible explanation for these observations is that hydridomethylsilenes undergo a facile isomerization to divalent dimethylsilylene. Cycloaddition of 1,1-dimethylsilene to allene at 600°C in a flow vacuum pyrolysis system affords the first synthesis of 2-methylene-1,1-dimethylsilacyclobutane and smaller amounts of six other products. For static pyrolysis at 421°C, the 2-methylene-1,1-dimethyIsilacyclobutane isomerizes to 1,1-dimethylsilacyclopentenes. The kinetics of gas phase thermal decomposition of cyclopropyltrimethylsilane has been studied over the temperature range, 689.6-751.1 K at pressures near 14 torr. The Arrhenius parameters for formation of allyltrimethylsilane are k_1(sec^-1)=10^14.3 ± 0.1 exp(-56.5 ± 0.2 kcal mol^-1/RT) and those for the formation of E- and Z-1-propenyltrimethyIsilane are k_2(sec^-1)=10^14.9 ± 0.3 exp(-61.9 ± 0.8 kcal mol^-1/RT). The difference between activation energies has been interpreted in terms of anchimeric assistance or the β effect of the silicon atom. The syntheses of 3-trimethylsilyl-1-pyrazoline and 1-trimethyl-2-pyrazoline are described. The thermal decomposition of either pyrazoline affords four different products along with elimination of a nitrogen molecule. It was suggested that the relative rates of methylene-hydrogen migration to radical centers α and γ to silicon are approximately equal. The thermal isomerization of 3-trimethylsilyl-1-pyrazoline to 1-trimethylsilyl-2-pyrazoline has been investigated kinetically at 65°C by proton NMR spectroscopy and the reverse reaction has been detected by gas phase pyrolysis.
Isozymes and In Vivo Activity of Triosephosphate Isomerase
The distribution of isozymes of triosephosphate isomerase was normal in all human tissues examined. This finding argues against the existence of tissue-specific isozymes. Normal distributions of isozymes were also found in patients with cri-du-chat syndrome. Thus it is unlikely that a gene for triosephosphate isomerase is located on the short arm of chromosome five in man. When triosephosphate isomerases from a wide range of species were examined by starch gel electrophoresis, definite evolutionary patterns were found. Kinetic studies were conducted on human triosephosphate isomerase under conditions simulating the intracellular environment of the erythrocyte. Calculations using the kinetic parameters obtained indicate that even in triosephosphate isomerase deficiency disease, enough enzyme activity remains that the rate of glycolysis should not become inhibited.
Ketene Carbodiimide Cycloadditions
It was proposed to study the cycloaddition of ketenes and carbodiimides in some detail. The first objective was to investigate the general applicability of the reaction as a tool for the synthetic organic chemist in the preparation of a new class of substituted β-lactams; i.e., imino-β-lactams. It was proposed for this part of the research problem to look for the intermediate, either directly or indirectly, by trapping experiments. It was further proposed to study substituent effects in the ketene and carbodiimide and also Investigate the effect of solvent polarity on the reaction rate. From these data, it was hoped that the mechanism of the cycloaddition reaction could be elucidated.
Ketene Reactions: I. The Addition of Acid Chlorides to Dimethylketene ; II. The Cycloaddition of Ketenes to Carbonyl Compounds
Part I describes the addition of several acid chlorides to dimethylketene. The resulting 3-ketoacid chlorides were isolated and characterized. Part II describes the cycloaddition of several aldoketenes to chloral. The ketenes were generated in situ by dehydrohalogenation and dehalogenation of appropriately substituted acyl halides.
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