Three nitrogen-bridgehead, bicyclic urethanes, 1-aza-8-oxa-bicyclo[4.3.0]nonan-9-one, I, 1-aza-3-oxabicyclo[3.3.1]nonan-2-one, II, and 1-aza-6-oxabicyclo[3.2.1]octan-7-one, III, were synthesized. UNFORMATTED TABLE OR EQUATION OMITTED - PLEASE SEE DISSERTATION. Contrary to popular opinion and in formal disagreement with Bredt's Rule, conformationally strain-free bicyclic urethanes II and III are stable because of N-C=O -O resonance interaction. The demand of the carbonyl for electrons is satisfied by N and O atoms. Urethane II was synthesized by cyclization of 3-chloroformyloxymethylpiperidine hydrotosylate using triethylamine or by refluxing 3-hydroxymethylpiperidinocarbamoyl chloride with excess triethylamine. To satisfy the N-C = 0 and O-C = 0 electron donation, the molecule does not exist in the two-chair form other [3.3.1] systems do, but in a form between the two-chair, boat-chair and flat-chair forms. Its low carbonyl stretching frequency, resistance to hydrolysis and resistance to ring-opening polymerization, all show that the molecule is not strained. 1-Aza-6-oxabicyclo[3.2.1]octan-7-one, III, was synthesized by the reaction of 3-hydroxypiperidinocarbamoyl chloride with four equivalents of triethylamine. It absorbed at 1770 cm⁻¹, 20 cm⁻¹ higher than Ḭ. Water hydrolyzed it at room temperature and phosphoric acid polymerized it at 105°, but it resisted ring-opening polymerization by potassium t-butoxide and p-toluenesulfonic acid in DMSO. As a reference, Ḭ was synthesized in five ways. It was obtained by the action of triethylamine on 2-chloroformyloxymethylpiperidine hydrostosylate, by reacting a mixture of triethylamine. phosgene and 2-hydroxymethylpiperidine, and by refluxing ethylene carbonate, diphenylcarbonate or di-t-butyl tricarbonate with 2-hydroxymethylpiperidine. Urethane I was stable in boiling water for 24 hr, and aqueous sodium hydroxide for two days. It showed no signs of polymerization after heating for extended periods with p-toluenesulfonic acid, phosphoric acid or potassium t-butoxide. The rearrangements of chloroformyloxypiperidines to hydroxypiperidinocarbamoyl chlorides were performed, and unsuccessful attempts were made to synthesize 1-aza-3-oxabicyclo[2.2.2]nonan-2-one.

No description available.

Thesis (Ph. D.)--University of Adelaide, Depts. of Physical and Inorganic Chemistry and Chemical Engineering, 1993. / Includes bibliographical references.

Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 1998. / Field project. Includes bibliographical references.

Inaug.-diss.--München. / Includes bibliographical references.

A thesis presented in the University of the Witwatersrand for the degree of Doctor of Philosophy / AC 2018

Includes bibliographical references / xi, 228 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Depts. of Physical and Inorganic Chemistry and Chemical Engineering, 1993

Neste trabalho uretanas livres de isocianatos produzidas a partir de um precursor bis(ciclocarbonato) oligomérico contendo segmentos de poli(dimetil siloxano) (CCPDMS) foram sintetizadas. Para tal, utilizou-se diferentes aminas primárias como a 3-aminometil-3,5,5 trimetilciclohexilamina (IPDA) e as monoaminas 3-aminopropil(trietóxisilano) (APTES), feniletilamina (PEA), catecol amina (dopamina) e um decapeptídeo derivado da proteína de adesão de mariscos (mefp-1).O precursor oligomérico CCPDMS foi produzido por fixação de dióxido de carbono em anéis epóxi catalisado por um sal quarternário de amônio, o brometo de tetraetilamônio (BTA). O precursor CCPDMS foi então reagido com as aminas por meio de polimerização por abertura de anel formando hidroxiuretanas derivadas de PDMS (PDMSUr) com diferentes terminações de cadeia. Tendo como terminador de cadeia o APTES, foi possível produzir um material híbrido com domínios inorgânicos de sílica organicamente modificada (ormosil) interligadas com a parte orgânica de PDMS por meio de ligações uretana. Nesta matriz híbrida foram adicionadas diferentes porcentagens mássicas de ácido fosfotúngstico (PWA), variando entre 1% a 55%. Os materiais foram caracterizados quanto à sua estrutura química por técnicas espectroscópicas (Ressonância Magnética Nuclear, Infravermelho, Espectroscopia de Fotoelétrons, MALDI-ToF), propriedade anti-corrosão (espectroscopia de impedância eletroquímica, polarização potenciodinâmica), propriedades superficiais (energia livre superficial, nanoindentação), análise morfológica (Microscopia Eletrônica de Varredura), estabilidade térmica (Análise Termogravimétrica), testes de adesão (pull-off-test e cisalhamento), testes microbiológicos (adesão de bactérias, tecidos e citotoxicidade), além de ensaios de fotocromismo. O polioxometalato PWA conferiu propriedades fotocrômicas aos filmes híbridos de PDMSUr com máxima absorbância de 1,6 u.a após irradiação por luz ultra-violeta (UV). PDMSUr híbridas com ou sem PWA foram testadas como adesivos para vidro, alumínio, aço (SS316L) e liga de titânio (Ti6Al4V) apresentando valores de força de adesão entre 2-7 MPa. Filmes de PDMSUr preparados em diferentes substratos apresentaram comportamento bacteriostático frente à adesão de Escherichia coli (E.coli) e Lactobacillus casei (L.casei). A PDMSUr biomimética terminada por grupos catecóis foi capaz de formar camadas em superfícies metálicas apresentando boa estabilidade frente à remoção da camada depositada por lavagem com etanol. / Free isocyanate urethanes produced from an oligomeric precursor bis(cyclic carbonate) bearing poly(dimethylsiloxane) (CCPDMS) were synthesized in this work. Different primary amines such as 3-Aminomethyl-3,5,5-trimethylcyclohexylamine (IPDA) and monoamines 3-aminopropyltriethoxysilane (APTES), phenylethylamine (PEA), catechol amine (dopamine) and a decapeptide derived from marine mussel foot protein (mefp-1). The precursor cyclic carbonate CCPDMS was obtained from carbon dioxide fixation into epoxy rings catalized by a quaternary ammonium salt, tetraethylamonium bromide (TEAB). The precursor CCPDMS was reacted with the different amines by ring opening polymerization affording the formation of hydroxyurethanes PDMS derived (PDMSUr) with different chain terminations. Using APTES as chain terminator was feasible to obtain a hybrid material containing inorganic domains of organically modified silica (ormosil) interconnected to the organic part PDMS through urethane bond. In this hybrid matrix different mass percentages, varying from 1%wt to 55 wt%, of phosphotungstic acid (PWA) were added. The materials were characterized regarding their chemical structure by spectroscopic techniques (Nuclear Magnetic Resonance, Infrared, and X-ray photoelectron spectroscopy), mass spectrometry (MALDI-ToF and GPC), anti corrosive property (Electrochemical Impedance Spectroscopy and potentiodynamic polarization), surface properties (free surface energy, nanoindentation), morphology (Scanning Electron Microscopy), thermal stability (Thermogravimetric analysis), adhesion strenght measurements (pull-off-test and lap-shear), microbiologic assays (bacteria adhesion, tissue adhesion and citotoxicity test) besides photochromic assays. The polyoxometalate PWA provided photochromic property to the PDMSUr hybrid films presenting a maximum absorbance of 1.6 a.u after ultraviolet (UV) irradiation. Hybrids PDMSUr with or without PWA were tested as adhesive for glass, aluminium, steel (SS316L) and titanium alloy (Ti6Al4V) showing adhesion strength values ranging from 2-7 MPa. PDMSUr films prepared on different substrates showed bacteriostatic behavior against Escherichia coli (E.coli) and Lactobacillus casei (L.casei). The biomimetic PDMSUr catechol endcapped was able to form a layer on metallic surfaces showing good stability after rinsing with ethanol.

Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2005. / Includes bibliographical references (p. 57-61).

Orientador: Maria Isabel Felisberti / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T21:04:55Z (GMT). No. of bitstreams: 1 Alves_SabrinadeSousa_M.pdf: 1156094 bytes, checksum: 5b56bbbe834e47047d9d7c14d74333c1 (MD5) Previous issue date: 2008 / Resumo: Materiais poliméricos com propriedades como biodegradabilidade e biocompatibilidade, como o poli(hidroxibutirato) (PHB) e a poli(caprolactona), vêm sendo amplamente estudados para aplicações com alto valor agregado, como a área biomédica. A síntese de poliuretanas contendo blocos de PHB e PCL visa a obtenção de um material que mantenha as características de biodegradabilidade e biocompatibilidade e que possua propriedades mecânicas diferentes dos materiais de partida, o que viabiliza um aumento na gama de aplicações destes polímeros. Neste trabalho, polióis de PHB e PCL com massa molar inferior a 6000 g mol foram obtidos através de reações de glicólise. Diferentes rotas e condições experimentais, utilizando diferentes solventes, catalisadores, tempo e temperatura, foram testadas para esta reação. A caracterização destes oligômeros foi feita através de análise de RMN H e C, DSC, TGA, índice de hidroxila e GPC. Na segunda etapa do trabalho, foram realizadas reações dos oligômeros obtidos com hexametileno diisocianato (HDI), um isocianato de cadeia linear de baixo poder carcinogênico. As estruturas químicas das poliuretanas obtidas nesta reação foram caracterizadas por FTIR e RMN H e C, as propriedades térmicas caracterizadas por DSC, TGA e DMA, físicas através de GPC e teste de solubilidade para verificar existência de reticulação / Abstract:The synthesis of polyurethanes containing PHB and PCL blocks aims to obtain materials with controlled mechanical properties maintain biodegradable and biocompatible polymers such as poly(hidroxybutyrate) (PHB) and poly(caprolactone) (PCL) have been largely studied. The synthesis of polyurethanes containing blocks of PHB and PCL aims to obtain materials with controlled mechanical properties maintaing the biodegradability and biocompatibility. In this work, polyols of PHB and PCL with molar weight less than 6000 g mol were obtained from glicolise reactions with ethylene glycol. The polyols were characterizated by RMN H e C, DSC, TGA, hydroxyl index and GPC. Diferent routes and experimental conditions, using diferent solvents, catalysts, time and temperature were tested. In a second step of this research reactions between the polyols and hexamethylene diisocianate (HDI), an alifatic isocianate with low carcinogenic toxicity were conduced in order to obtin polyurethanes. The chemical structure of polyurethanes obtained was characterized by FTIR and RMN H e C, thermal properties were characterized by DSC, TGA and DMA em physical properties by GPC and solubility test / Mestrado / Físico-Química / Mestre em Química