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Articles 181 - 195 of 195
Full-Text Articles in Chemistry
Tailoring Branching For Poly (Arylene Ether)S Via Reactivity Ratio Controlled Polymerizations, Amanda Ike
Tailoring Branching For Poly (Arylene Ether)S Via Reactivity Ratio Controlled Polymerizations, Amanda Ike
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The ability to control physical and mechanical properties of polymer systems has become an important aspect of polymer science. In order to tailor the branching in polymer systems, an understanding into the reactivity of the electrophilic sites in the monomer is important. Kinetic methods have been explored in order to determine the reactivity of monomers in preparing poly(arylene ether)s and to predict the degree of branching that will occur in a polymer of this kind. The reactivity of AB2 sulfones and phosphine oxides was explored, along with the reactivity of ABB'B'' sulfones. NMR spectroscopy was used as a probe into …
Preparation And Derivatization Of Novel Sydnonimines And Their Esters, Timothy Luke Teschler
Preparation And Derivatization Of Novel Sydnonimines And Their Esters, Timothy Luke Teschler
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Some years ago, we reported that 3-phenylsydnone underwent dilithiation to yield the dilithio species, upon treatment with n-butyllithium. Subsequent reactions with electrophiles led to variously substituted aryl sydnones, dependent on the nature of the electrophile employed. Sydnonimines, exocyclic nitrogen analogs of sydnones, exhibit interesting biological properties and, accordingly, it was of value to explore whether or not the dilithiation approach could be extended to such species. In the present work a series of N-6-ethoxycarbonyl-3-arylsydnonimines were synthesized from the corresponding sydnonimine hydrochlorides in moderate yields (22-77%). Attempted dilithiations of N-6-ethoxycarbonyl-3-arylsydnonimines and trapping with iodine proved to be problematic, yielding only the …
Formation Of A Sydno[3,4- A]Indolone And Reactions Thereof, Ryan Christopher Vikan
Formation Of A Sydno[3,4- A]Indolone And Reactions Thereof, Ryan Christopher Vikan
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In the present work, a synthetic route to the formation of a sydno[3,4- a]indolone was explored in the hope of attaining the first example of a fused-ring sydnone with an sp2-hybridized bridge. Formation of this product and exploration of its chemical behavior was anticipated to be of particular interest to the formation of NO-releasing prodrugs. A direct synthetic pathway to yield the target sydnoindolone starting from 3-(2-methoxycarbonylphenyl)sydnone and reaction with a base was proposed and explored. Attempted formation and isolation of the target sydnoindolone proved impossible under a variety of different conditions, undoubtedly due to the instability of this …
Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams
Water Solubility Characteristics Of Hydrophobically Modified Polyethyleneimines, Jennifer N. Williams
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Commercially available polyethyleneimines varying in molecular weights and viscosities were synthetically modified in order to increase their hydrophobicity when dissolved in water. Used as additives for inkjet industry inks, these polymers have been designed to promote interaction between formulated inks and paper, while increasing the water-fastness of these water-soluble inks once they are dried on bond paper. Waterfastness, the ability of an ink to maintain print integrity once it becomes wet, as well as optical density, solubility, pH, molecular weight, polydispersity and viscosity are amongst the characteristics analyzed. The modifications of these polyethyleneimines (PEis) with alkyl bromides and alkyl epoxides …
Exploration Of Iron And Cobalt Core-Shell Nanoparticles Via Thermal And Microwave Polyol Synthesis, Hope M. Klukovich
Exploration Of Iron And Cobalt Core-Shell Nanoparticles Via Thermal And Microwave Polyol Synthesis, Hope M. Klukovich
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Thermal and microwave polyol methods were investigated in the synthesis of various iron and cobalt core-shell nanoparticles. The reaction involved 1 mmol of an Fe+2 or Co+2 salt, bis-acetylacetanato [(Acac)2] iron (II), cobalt (Acac)2 or iron (II) acetate along with 1 mmol of a surfactant capping agent. The salt was reduced with 2 mmol of a 1,2 diol. When 1,2-hexadecanediol solid was used as a reducing agent, it was dissolved along with the metal salt and capping agent in octyl ether. When 1,2-hexanediol liquid was used as the reducing agent, it was also the solvent, and octyl ether …
Pyrrole Carboxamides As Potential Carbonic Anhydrase Inhibitors, Nishrin Ismailbhai Marketwala
Pyrrole Carboxamides As Potential Carbonic Anhydrase Inhibitors, Nishrin Ismailbhai Marketwala
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Carbonic anhydrases (CAs) are metalloenzymes that catalyze the reversible interconversion of CO2 and bicarbonate. We recently initiated a screen of a broad range of indoles and pyrroles possessing acyl-, carboxyl-, amido-, sulfonyl-, sulfamyl- and oxime- functionalities as potential inhibitors of á-CA II isozyme. As slight inhibition was observed in the case of 2-carboxamido-1-(phenylsulfonyl)pyrrole, and aware that pyrrole carboxamide derived sulfonamides had been previously demonstrated to possess CA inhibition, we sought to prepare a series of 1-(phenylsulfonyl)pyrrole-2-carboxamides but lacking a sulfonamide moiety to ascertain if the activity in our case might be due to a hitherto unrecognized pyrrole pharmacophore. To this …
The Modeling Of Solubility, Frank Christopher Campanell
The Modeling Of Solubility, Frank Christopher Campanell
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In this work the solubilities of gases in liquids and liquids in liquids were modeled using both physical properties and topological descriptors of the solutes. Quantitative structure-activity relationship (QSAR) methods were employed to create single-linear regression (SLR) and multiple-linear regression (MLR) models of the solubilities. Factor analysis was employed to determine the number of significant factors present in the solubilities. The solubilities of monoalcohols in water, halogenated alkanes in water, gases in water, gases in alkanes, and gases in alcohols were examined and modeled.
Bismuth Triflate Catalyzed Friedel-Crafts Acylations Of Sydnones, Jennifer Ann Fisher
Bismuth Triflate Catalyzed Friedel-Crafts Acylations Of Sydnones, Jennifer Ann Fisher
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In the present work, suitably functionalized arylsydnones were used to synthesize a variety of 4-acylsydnones and diacyl sydnones, both as potential precursors to novel sydnoquinolines.The approach to the diacyl species is based on the discovery that activated sydnonesbrominate in both the 4 position of the sydnone ring and on the phenyl ring. Thus, it seemed likely that Friedel-Crafts reactions on an activated sydnone would give diacylated species for McMurray coupling to sydnoquinolines. Friedel-Crafts acylations on the 4 position of the sydnone ring have been achieved in high yields using 4 equivalents of various alkyl anhydrides, 25 mol % of bismuth …
Electronic To Vibrational Energy Transfer From Cl* (3 2P1/2) To N2O(Ν1): Failure Of A Simple Kinetic Mechanism, Brian Brumfield
Electronic To Vibrational Energy Transfer From Cl* (3 2P1/2) To N2O(Ν1): Failure Of A Simple Kinetic Mechanism, Brian Brumfield
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Experimental kinetic studies were carried out examining the electronic to vibrational (E-V) energy transfer from spin-orbit excited Cl*(3 2P1/2 , 882 cm-1) to N2O(ν1) (symmetric stretch 1285 cm-1). All studies were carried out in the gas phase at room temperature (298 ± 2 K). Cl* was generated by pulsed laser photolysis of ICl at 532 nm in the presence of various mixtures of N2O, ICl,Ar, and SO2. Time-resolved IR signals of N2O(ν1) fluorescence at 7.8 μm were analyzed to obtain rate coefficients …
Sonogashira Coupling Routes To Ortho-Alkynl-And- Fused-Ring Sydnones, Andrew John Weisner
Sonogashira Coupling Routes To Ortho-Alkynl-And- Fused-Ring Sydnones, Andrew John Weisner
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In the present work, suitably functionalized arylsydnones were used to synthesize a variety of ortho-alkynyl sydnones both as potential precursors to novel sydnoquinolines and to provide non-linear optical (NLO) species of interest to Wright-Patterson Air Force Base (WPAFB). The versatile intermediate, 3-(2-(trimethylsilylethynyl)phenyl)sydnone, was prepared in good yield by the coupling of 3-(2-iodophenyl)sydnone with trimethylsilyl acetylene under Sonogashira conditions. From this intermediate, several ortho-alkynyl sydnones were prepared via a one-pot desilylation with tetrabutylammonium fluoride and Sonogashira coupling with para-substituted aryl iodides. In addition, a three-reaction-in-one-pot procedure was developed to access some of these species directly from 3-(2- iodophenyl)-sydnone. Subsequent reaction of …
Selected Synthetic Studies Of Nlo Pi-Bridges And Thermally Stable Monomers, Stacey Marie Fauley
Selected Synthetic Studies Of Nlo Pi-Bridges And Thermally Stable Monomers, Stacey Marie Fauley
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The molecular weights of two series of PEEK polymers were determined using gel permeation chromatography (GPC). The first series contains oxyalkylene linkages. The other series contains oxyethylene linkages. The synthesis of several thermally stable monomers has been investigated. These monomers include 9,9-dihexylfluorene-2,7-dicarboxaldehyde, 2,7-bis(bromomethyl)-9,9- dibutylfluorene and 2,7-bis(hydroxymethyl)-9,9-diethylfluorene. These monomers can be used to form polymers that will contain short conjugated segments separated by nonconjugated segments. The synthesis of 50 g of each of the following monomers was accomplished: bis(3-methylphenyl) phenylphosphine oxide, bis(4-methylphenyl)phenylphosphine oxide, bis(3- carboxyphenyl)phenylphosphine oxide and bis(4-carboxyphenyl)phenylphosphine oxide. These monomers will be used in a polymerization to form polybenzoxazoles. The …
The Synthesis Of Bromoethoxy And Vinylbenzyloxy Substituted Nlo Chromophores, Michael Joseph Matuszewski
The Synthesis Of Bromoethoxy And Vinylbenzyloxy Substituted Nlo Chromophores, Michael Joseph Matuszewski
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Multiphoton-absorption processes have recently attracted growing interest because of the potential impact on a wide spectrum of applications, ranging from data storage to photodynamic therapy. From the materials standpoint, particular interest is centered in designing chromophores that exhibit a large two-photon cross-section. The current research is focused on establishing synthetic routes that lead to the formation of derivatives of N,N-diphenyl-(7-benzothiazol-2-yl)-9,9-diethyl-9H-fluoren-2-ylamine which contain meta functionalization. A bromoethoxy functionalized chromophore, N-phenyl-N-(3-(2-bromoethoxy)phenyl)-7-(benzothiazol-2-yl)-9,9-diethyl-9H-fluoren- 2-ylamine , was synthesized and used as a polymer pendent while a vinylbenzyloxy chromophore, N-phenyl-N-(3-(4-vinylbenzyloxy)phenyl)-7- (benzothiazol-2-yl)-9,9-diethyl-9H-fluoren-2-ylamine, was synthesized as a hydrosilation substrate. A compound containing three chromophores, 1,3,5-tris(3-(N-phenyl- 4-(7-(benzothiazol-2-yl)-9,9-diethyl-9H-fluoren-2- ylanilino)phenoxymethyl)benzene, has …
The Functionalization Of Thermally Stable Third-Order Nlo Chromophores, James Richard Sawyer
The Functionalization Of Thermally Stable Third-Order Nlo Chromophores, James Richard Sawyer
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There is a need to functionalize NLO chromophore systems to incorporate them into polymeric matricies by covalent attachment. The functionalization of a series of NLO chromophores based on the N,N-diphenyl-N-[7-(2-benzothiazolyl)-9,9-diethyl-2- fluorenyl ]amine structure has been investigated. All the chromophores were synthesized from the intermediate chromophore N-phenyl-N-[4-(4-bromophenyl)phenyl ]-N-[7-(2- benzothiazolyl)-9,9-diethyl-2-fluorenyl ]amine which was prepared by a six-step process. Bromination of fluorene yielded 2,7-dibromo-fluorene which could be converted to 2,7- dibromo-9,9-diethylfluorene by alkylation with ethyl iodide in DMSO.Reaction of 2,7- dibromo-9,9-diethylfluorene with one equivalent of butyl lithium followed by reaction with DMF provides 2-bromo-7-formyl-9,9-diethylfluorene.Condensation of 2-bromo-7- formyl-9,9-diethylfluorene and 2-aminobenzenethiol in DMSO results in …
Studies Directed At The Synthesis Of Trialkoxysilyl Substituted Nlo Chromophores, Ida J. Kuhr
Studies Directed At The Synthesis Of Trialkoxysilyl Substituted Nlo Chromophores, Ida J. Kuhr
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The synthesis of trialkoxyalkyl substituted NLO chromophores has been investigated. The chromophore 2-(7-(3-hydroxydiphenylamino)-9,9-diethyl-2-fluorenyl)-benzothiazole was prepared by a five step process. Bromination of fluorene yielded 2,7-dibromo-fluorene which could be converted to 2,7-dibromo-9,9-diethylfluorene by alkylation with ethyl iodide in DMSO.Reaction of 2,7-dibromo-9,9-diethylfluorene with one equivalent of butyl lithium followed by reaction with DMF provides 2-bromo-7-formyl-9,9-diethylfluorene. Condensation of 2-bromo-7-formyl-9,9-diethylfluorene and 2-aminobenzenethiol in DMSO results in the formation of 2-(7-bromo-9,9-diethyl-2-fluorenyl)benzothiazole. The conversion of 3-hydroxydiphenylamine to 3-benzyloxy-diphenylamine was accomplished with benzyl bromide and potassium carbonate in DMF. A palladium catalyzed coupling of 3-benzyloxydiphenylamine and 2-(7-bromo-9,9-diethyl-2-fluorenyl)benzothiazole provided 2-(7-(3-hydroxydiphenyl-amino)-9,9-diethyl-2-fluorenyl)benzothiazole. Several attempts to alkylate 2-(7-(3-hydroxydiphenylamino)-9,9-diethyl-2-fluorenyl)benzothiazole with trimethoxysilylmethyl chloride …
Synthesis Of Benzoxazoles Containing Allyl Crosslinking Sites Via Claisen Rearrangements, Leslie K. Hutson
Synthesis Of Benzoxazoles Containing Allyl Crosslinking Sites Via Claisen Rearrangements, Leslie K. Hutson
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The reaction of diethyl 2,5-dihydroxyterephthalate with allyl bromide/K2CO3 in DMF followed by hydrolysis provided 2,5-di(allyloxy)terephthalic acid. The conversion of 2,5-di (allyloxy)terephthalic acid to 1,4-di(2-benzoxazolyl)-2,5-di(allyloxy)benzene in PPSE was unsuccessful. However, the reaction of 1,4-di(2-benzoxazolyl)-2,5- dihydroxybenzene with allyl bromide/K2CO3 provided 1,4-di(2-benzoxazolyl)-2,5- di(allyloxy)benzene. DSC analysis indicated that 1,4-di(2-benzoxazolyl)-2,5- di(allyloxy)benzene undergoes a Claisen rearrangement to the corresponding diallyl product. The synthesis of 2-allyloxy-1,4-di(2-benzoxazolyl)benzene was carried out using 2-hydroxy-1,4-di(2-benzoxazolyl)benzene as starting material. DSC analysis was inconclusive with respect to a Claisen rearrangement. The reaction of 2-allyloxybenzoic acid with 2,2-bis(3-amino-4-hydroxyphenyl)-1,1,1,3,3,3-hexafluoropropane in PPSE was unsuccessful but the reaction of 2,2-bis(2-(2-hydroxyphenyl)-5-benzoxazolyl)-1,1,1,3,3,3-hexafluoropropane with allyl bromide/K2CO3 in DMF provided 2,2-bis(2-(2- …