Investigations pertaining to the rhodium(I)-catalyzed addition of arylboronic acids to (arylsulfonyl)acetonitriles were undertaken. The resulting carbon-carbon bond forming reaction has led to the efficient synthesis of novel stereoselective (Z)-β-sulfonylvinylamines, which upon acidic hydrolysis, afford useful β-keto sulfones possessing a diverse range of aryl and sulfonyl substituents. The synthetic utility of these (Z)-β-sulfonylvinylamines was subsequently explored by generating the corresponding 1-aza-allyl anion equivalents under basic conditions. This interesting anionic intermediate was then introduced to various α,β-unsaturated systems to produce a diverse array of functionalized pyridine derivatives including unsymmetrical polysubstituted pyridines.

Investigations pertaining to the rhodium(I)-catalyzed addition of arylboronic acids to (arylsulfonyl)acetonitriles were undertaken. The resulting carbon-carbon bond forming reaction has led to the efficient synthesis of novel stereoselective (Z)-β-sulfonylvinylamines, which upon acidic hydrolysis, afford useful β-keto sulfones possessing a diverse range of aryl and sulfonyl substituents. The synthetic utility of these (Z)-β-sulfonylvinylamines was subsequently explored by generating the corresponding 1-aza-allyl anion equivalents under basic conditions. This interesting anionic intermediate was then introduced to various α,β-unsaturated systems to produce a diverse array of functionalized pyridine derivatives including unsymmetrical polysubstituted pyridines.

Cysteine proteases are a class of proteolytic enzymes, which are involved in a series of metabolic and catabolic processes, such as protein turnover, digestion, blood coagulation, apoptosis, fertilization and cell differentiation, and the immune response system. The development of novel potent and selective inhibitors for cysteine proteases has therefore gained increasing attention among medicinal chemists. In this thesis we have reported the design, synthesis, and evaluation of several peptidyl inhibitors for clan CA and clan CD cysteine proteases. We have continued the investigation of dipeptidyl vinyl sulfones as potent and selective inhibitors for dipeptidyl peptidase I (DPPI), a lysosomal cysteine protease, which is involved in the processing of intracellular proteases, such as granzymes. We have found that DPPI tolerates negatively charged amino acid residues in the P2 position with inhibition rates of 7,600 M-1s-1. Dipeptidyl vinyl sulfones with positively charged amino acid residues at the P1 position, however, do not inhibit DPPI at all. A second project focused on the epoxidation of the double bond of the vinyl sulfone moiety of the dipeptidyl vinyl sulfones. Instead of epoxidizing the double bond, we found that an isomerization had occurred. The newly formed compounds were determined to be allyl sulfones. We tested this new class of inhibitors with clan CA proteases and obtained inhibition rates of 560 M-1s-1 for Cbz-Leu-Phe-AS-Ph with calpain I. Two new classes of compounds for the clan CD protease S. mansoni legumain were designed, synthesized, and evaluated. Aza-peptidyl epoxides were found to be potent and selective inhibitors of S. mansoni legumain with IC50’s as low as 45 nM. Aza-peptide Michael acceptors were derived from the aza-peptide epoxide design and synthesized in an analogous fashion. The aza-peptide Michael acceptors inhibited S. mansoni legumain with even lower IC50’s, as low as 10 nM. However, the aza-peptide Michael acceptors react with thioalkylating agents contained in the buffer, such as DTT. The rates of degradation were determined spectroscopically, and half-lives of 3 to 20 minutes were measured. This observation gave us insights into the enzymatic mechanism and allowed us to determine the point of attack for the legumain active site cysteine thiol.

Acrylamide based hydrogels were synthesized through copolymerization reaction of allyl methacrylate with acrylamide. Copolymerization reactions were carried out with solution polymerization in tetrahydrofuran by using &alpha / -&alpha / -azoisobutyronitrile as an initiator at 60 0 C. Three copolymer compositions were studied having 5, 15, 25 molar percentage of allyl methacrylate as feed concentrations. The synthesized copolymers were characterized by FTIR, NMR, DSC, TGA and GPC. 1H-NMR spectra were used to confirm the chemical structures of the copolymers and to determine the comonomer compositions of the copolymers. DSC and TGA analysis were conducted to determine the thermal properties of the copolymers and TGA results showed that copolymers have two step degradation behavior. Molecular weights of the copolymers were determined by GPC. Swelling capacities of the obtained hydrogels were investigated and swelling capacity of the gels reached to 77% as maximum value.

Abstract The reactivity and bonding of allyl groups (C3H5) on a Ag(111) surface have been investigated under ultrahigh vacuum conditions by temperature-programmed reaction/desorption (TPR/D) and reflection-adsorption infrared spectroscopy (RAIRS). The atomically clean surface was achieved by Ar+ sputtering and verified by AES. The surface crystallinity was assured by LEED. Surface -bound allyl groups were generated by dissociative adsorption of allyl halides. Our study shows that the C-X (X= I or Cl) bond can be ruptured below 200K to render adsorbed allyl species. Upon further heating, three gas-phase products were detected at ~280 K, 295 K and 320 K in the TPR/D spectra, which are attributed to 1,5-hexadiene, allene, and propene, respectively. These results suggest that allyl undergoes

Made available in DSpace on 2015-03-26T13:30:35Z (GMT). No. of bitstreams: 1 texto completo.pdf: 217734 bytes, checksum: 6fd7a4c6b5089dddf92260f4cc930663 (MD5) Previous issue date: 2011-03-16 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to evaluate the toxicity of the essential oil of mustard (EOM) for adults of five populations of Sitophilus zeamais (Coleoptera: Curculionidae) and the influence of the essential oil on the locomotory behavior of the populations. EOM was used with 90% of allyl isothiocyanate volatile component (ITCA), diluted in soybean oil at 1:9 v/v to obtain a 9% solution of ITCA. EOM was applied on filter paper placed in Petri dishes (5.0 cm diameter). The dishes were covered with organza and placed inside glass jars of 0.8 L, and 50 adult insects were transferred to the jars, which were kept closed for 48 hours. EOM was used at concentrations ranging from 1.2 to 2.8 μL L-1. The S. zeamais populations used were from Abre Campo, Machado, Paracatu, Piracicaba and Tunápolis. The toxicity of EOM was evaluated by determining the lethal concentrations (CL) to 50 (LC50) and 95% (LC95) of adult insects, which were then used to estimate the toxicity ratio. The following locomotory behavioral parameters were studied: walked distance, walking velocity, resting time, and number of stops, as well as the number of takeoffs and flying height of the insects. Additionally, the instantaneous rates of increase (ri), the respiration rate (CO2 production) and body mass were evaluated for all populations. The most susceptible population to EOM was Piracicaba for wich the lowest LC50 was obtained (1.49μL L-1). This concentration was used for all the other assays treated with EOM, except the instantaneous rate of population growth, which hand no EOM treatment. The Paracatu population showed the highest LC50 (2.97 μL L-1) and LC95 (6.82 μL L-1) while Machado showed the lowest LC95 (2.16 μL L-1). The toxicity ratio based on the LC50 ranged from 1.08 to 1.99 times, and from 0.76 and 2.42 times based on the LC95. The slopes of the concentration mortality curves varied among the populations from 4.56 ± 0.72 (Paracatu) to 13.14 ± 0.75 (Tunápolis). The distance walked did not significantly differ between insects treatead with EOM and control or among populations. However, regarless of the population, the resting time of the insects was reduced by treatment with EOM. The other walking parameters (walking velocity and number of stops), flight parameters (flying height and number of takeoffs), respiratory rate, and body mass, the only varied among the populations, but no difference existed for insects exposed or not exposed to EOM. In conclusion, the EOM was toxic to the five populations of S. zeamais and did not promote major changes in the locomotory behavior of the insects. Different locomotory behavioral patterns, respiratory rate, and body mass were observed in the S. zeamais populations, but with uniform response to mustard oil; these differences should be inherent to the genetic make up of the populations. / O objetivo deste trabalho foi avaliar a toxicidade do óleo essencial de mostarda (OEM) para adultos de cinco populações de Sitophilus zeamais (Coleoptera: Curculionidae) e verificar a influência do óleo essencial sobre o comportamento locomotor dos insetos. Foi utilizado OEM com 90% do componente volátil Isotiocianato alilo (ITCA), diluído em óleo de soja, na proporção de 1:9 v/v, para obter solução oleosa de 9% de ITCA. O OEM foi aplicado em papel-filtro colocado em placas de Petri (5,0 cm diâmetro), que foram cobertas com organza e colocadas no interior de frascos de vidro de 0,8 L, aos quais foram acrescentados posteriormente 50 insetos adultos. Os frascos foram mantidos fechados por 48h. Utilizou-se o OEM em concentrações variando de 1,2 a 2,8 μL L-1. As populações de S. zeamais utilizadas foram Abre Campo, Machado, Paracatu, Piracicaba e Tunápolis. Avaliou-se a toxicidade do OEM por meio da estimativa das concentrações letais (CL) para 50 (CL50) e 95% (CL95) dos insetos adultos. As CL50 e CL95 foram usadas para calcular as respectivas razões de toxicidade. Foram avaliadas também as características comportamentais de caminhamento: distância percorrida, velocidade de caminhamento, tempo de repouso e número de paradas, bem como as características de voo como número de decolagens e altura de voo dos insetos. Adicionalmente, foram avaliadas as taxas instantâneas de crescimento populacional (ri), as taxas respiratórias (produção de CO2) e massa corpórea para todas as populações. A população padrão de susceptibilidade foi a da cidade de Piracicaba, pois apresentou menor CL50 (1,49 μL L- 1). Esta concentração foi utilizada para todos os bioensaios tratados com o OEM, exceto para a taxa instantânea de crescimento populacional, em que não se utilizou o tramento com OEM. A população de Paracatu foi a que apresentou maior CL50 (2,97 μL L-1) e CL95 (6,82 μL L-1), enquanto Machado foi a população que apresentou menor CL95 (2,16 μL L-1). A razão de toxicidade com base na CL50 variou entre 1,08 e 1,99 vezes, e entre 0,76 e 2,42 vezes baseada na CL95. As inclinações das curvas de concentração-mortalidade variaram entre as populações, sendo menor (4,56 ± 0,72) para a população de Paracatu e maior (13,14 ± 0,75) para a de Tunápolis. Não houve diferença significativa na distância percorrida entre os tratamentos com OEM e controle, nem entre as populações. No entanto, o tempo de repouso dos insetos foi reduzido pelo tratamento com OEM em todas as populações. Para os outros padrões comportamentais de caminhamento (velocidade de caminhamento e número de paradas), de voo (altura de voo e número de decolagens), taxa respiratória e de massa corpórea, houve diferença apenas entre as populações, não diferindo quando na presença ou ausência do OEM. Com isso, conclui-se que o OEM foi tóxico para as cinco populações de S. zeamais e que este óleo não promoveu grandes alterações no comportamento locomotor dos insetos. Diferentes padrões comportamentais, respiratórios e de massa corpórea foram observados nas populações de S. zeamais, porém com uniformidade de resposta ao óleo de mostarda, sendo que estas diferenças devem ser inerentes à constituição genética das populações.

A primeira parte desta Tese incluiu a funcionalização em solução de polietileno linear de média densidade (LMDPE) com alil glicidil éter (AGE), na presença de peróxido de benzoíla (BPO) como iniciador de reações radicalares. A caracterização foi feita por espectroscopia no infravermelho com transformada de Fourier (FTIR) e o grau de funcionalização (GF) foi estimado por meio de duas curvas de calibração. Foi observado efeito do tipo de solvente sobre o GF. A segunda parte consistiu na funcionalização superficial por radiação ultravioleta (UV). Como monômeros foram usados AGE, anidrido maléico (MAH) e anidrido tetraidroftálico (THFAH). Como iniciadores, BPO e benzofenona (BP). A caracterização das superfícies foi realizada por medidas de ângulo de contato. THFAH apresentou a melhor performance. A terceira tratou da funcionalização por processamento reativo do LMDPE com AGE, na presença de BPO. A caracterização se deu por FTIR e o GF foi estimado conforme descrito acima. A funcionalização foi confirmada (indiretamente) por calorimetria diferencial exploratória, que evidenciou a diminuição do grau de cristalinidade com a funcionalização. Não foi possível confirmar a funcionalização por meio de análise elementar, termogravimetria e difração de raios X. A fragmentação das cadeias do LMDPE funcionalizado do ensaio 13 (e 13A) foi evidenciada por decréscimo no torque e nas propriedades mecânicas. Contudo, o índice de fluidez, surpreendentemente, diminuiu. Os valores relativamente superiores de resistência à tração e módulo de Young dos compósitos e blendas obtidos com LMDPE funcionalizado, contra os obtidos com LMDPE virgem, evidenciaram a interação favorável entre os grupos epóxidos inseridos nas cadeias do LMDPE e os grupos hidroxilas presentes no polissacarídeo. O aumento da adesão entre a matriz polimérica e as fibras de celulose foi confirmado por microscopia eletrônica de varredura e, qualitativamente, por quantidades relativamente maiores de resíduos remanescentes após extração em xileno sob refluxo. / The first part of this work included the functionalization in solution of linear medium density polyethylene (LMDPE) with allyl glycidyl ether (AGE), in the presence of benzoyl peroxide (BPO) as free radical reaction initiator. The characterization was made by Fourier transform infrared spectroscopy (FTIR) and the degree of functionalization was estimated by means of two calibration curves. The type of solvent influenced the DF. The second part comprised the surface functionalization by ultraviolet (UV) radiation. AGE, maleic anhydride (MAH) and tetrahydrophthalic anhydride (THFAH) were used as monomers and BPO and benzophenone (BP) as initiators. Contact angle measurements were used to characterize the surfaces. THFAH showed the best performance. The third part dealt with the functionalization by reactive processing of LMDPE with AGE, in the presence of BPO. FTIR was used to characterize the samples and the degree of functionalization was estimated as described above. The functionalization was (indirectly) confirmed by differential scanning calorimetry. The degree of crystallinity decreased with the functionalization. The functionalization couldn?t be confirmed by elemental analysis, thermogravimetry and X-ray diffraction. The chain scissions of the chemical modified LMDPE of trial 13 (and 13A) were evidenced by reduction of torque and mechanical properties. However, the melt flow index diminished. The favorable interaction between epoxide groups inserted on LMDPE chains and hydroxyl groups present in polysaccharide caused the increase in tensile strength and Young?s modulus values for composites and blends in relation to those obtained with virgin LMDPE. The increase in adhesion between the polymeric matrix and cellulose fibers was also confirmed by scanning electron microscopy and, qualitatively, by relatively large amounts of remaining residues after extraction in refluxing xylene.

The direct conversion of carbon–hydrogen bonds into valuable carbon-carbon and carbon-heteroatom bonds is a significant challenge to synthetic organic chemists. More than ever, chemists are employing Rh(III)-catalysts bearing cyclopentadienyl (Cp) ligands to transform otherwise inert C–H bonds. Furthermore, manipulating the sterics and electronics of the Cp ligand show significant impact on catalytic transformations. Our group has developed a library of CpˣRh(III)-precatalysts in hopes of enhancing known reactivity as well as discovering new C–H bond functionalizations. We have previously reported that N-enoxyphthalimides are a unique one-carbon component for the cyclopropanation of activated alkenes. In an effort to expand the scope to accessible alkenes, we have found a number of symmetrical unactivated alkenes undergo [2+1] annulation to afford intriguing spirocyclic cyclopropanes. Additionally, we have developed a Rh(III)-catalyzed diastereoselective [2+1] annulation onto allylic alcohols to furnish substituted cyclopropyl ketones. Notably, the traceless oxyphthalimide handle serves three functions: directing C–H activation, oxidation of Rh(III), and, collectively with the allylic alcohol, in directing cyclopropanation to control diastereoselectivity. Allylic alcohols are shown to be highly reactive olefin coupling partners leading to a directed diastereoselective cyclopropanation reaction, providing products not accessible by other routes. Next, an artifact of previous cyclopropanation reactions leads to the formation of a Rh-π-allyl complex. Attempts at 1,1-carboamination of alkenes are made using alkenes and nitrenoid precursors toward the 3-component synthesis of allylic amines. Stoichiometric studies help elucidate the mechanism and challenges. Lastly, efforts toward 1,2-carboamination of alkenes initiated by sp³ C–H bond activation are made with two different reactivity manifolds. Isolation of reaction intermediates are discussed as well as providing viable paths toward valuable products.

This study examined the feasibility of using (BETA)-cyclodextrins ((BETA)CDs), which are derived from starch, as agents to stabilize volatile and leachable biocides for the protection of wood and wood composites. The encapsulation of volatile natural antimicrobial compounds, such as allyl isothiocyanate (AITC) and essential oils (EOs), in βCDs was qualitatively confirmed by Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) method and the maximum inclusion yield was quantitatively estimated by ultraviolet-visible spectrophotometry (UV/VIS) while the partial fixation of leachable borates with βCD was confirmed by ATR-FTIR and nuclear magnetic resonance (NMR) techniques. The efficacy of the βCD complexes as wood preservatives of southern yellow pine and randomly Oriented Strand Board (OSB) was examined in soil block tests (AWPA E10-16 and E22-16 standard). The results indicate that (A) (BETA)CDs suppress the premature leaching of otherwise volatile natural compounds and suggest a novel approach to the application of volatile or water-immiscible natural preservatives for wood and wood composites protection; (B) (BETA)CD can be used as an agent for partial fixation of boric acid to form boric acid esters. However, the borate esters are susceptible to leach out after AWPA E11 test and not suitable for protection against Gloeophyllum trabeum and Postia placenta in outdoor conditions.

Isomerization is a synthetically useful technique to form the more stable internal alkene from terminal alkene feedstock. Unfortunately, these transformations form a variety of isomers without catalyst control. Z alkenes are thermodynamically challenging to form compared to their E counterparts but are useful in pharmaceutical, fragrance, and flavor industries, making them sought-after products. Therefore, catalysts targeting specific regio- and stereoisomers, particularly Z alkenes, will benefit many fields. This work analyzes several Mo(0) complexes as Z-2-alkene selective isomerization catalysts. Particular focus has been given to cis-Mo(CO)4(PCy3)(piperidine) due to easy purification and characterization. Substantial improvement to reported Z selectivities have been obtained with this complex, though disadvantages exist. To have a clearer understanding of the mechanism and source of Z selectivity, DFT analysis was completed, and a mechanism proposed. A rare rotation of hydride and carbonyl ligands was found, only reported in one prior Mo complex, that facilitates the isomerization. Key characteristics were discovered that will be applied to develop future iterations with the goal of reducing, or removing, the disadvantages of this system. / Chemistry