The problem with which this investigation is concerned is twofold. The initial part of the problem was to prepare a non-sterically demanding bidentate phosphine ligand, 1,2-bis-(Phosphino)ethane, (P-en), and to determine the kinetics of (P-en)Mo(CO)4 with phosphites via spectrophotometric methods in an attempt to determine if steric effects are directing the type of mechanism followed.

Abstract This thesis is divided into two parts. Part one presents a novel method for the synthesis of naphthalenes bearing aryl substituents. The novel route starts from three simple and readily available tetralones, α-tetralone, 6-methoxy-α-tetralone and 6,7-dimethoxy-α- tetralone. By means of standard Suzuki coupling methodology and aromatization methods, twelve aryl-substituted naphthalenes were synthesized from the tetralones over five steps in good yields. Some of the aryl-substituted naphthalenes synthesized have shown positive results when tested against malignant cancer cells. Part one also explains how unexpected cyclopropa[a]naphthalenes were obtained from 1-aryl-3,4-dihydro-2- naphthaldehydes by treatment with lithium aluminium hydride. The methodology developed in part one is further explored in part two of the thesis, which describes the synthesis of analogues of [1,1’]binaphthalenyl-2,2’-diol. A small library of twelve different biaryl diols was prepared from simple bromo(methoxy)naphthaldehydes that were synthesized in part one. The resultant biaryl diols were used in the design of twenty-two novel phosphite, phosphate, phosphoramidite and phosphoramidate ligands in which the phosphorus atoms are contained in either a nine-or an eight-membered heteroatom ring. However, these ligands are still to be tested in metal-catalyzed hydrogenation reactions.

Open-framework inorganic materials constitute an important area of study in materials chemistry, because of their potential applications in areas such as sorption and catalysis. After the discovery of nanoporous aluminium phosphates by Flanigen et al in 1982, there has been a tremendous growth in the area of porous solids. Most of them are based upon oxygen containing materials especially phosphates, and they exhibit fascinating architectures with unusual bonding and coordination environment. Besides metal phosphates and phosphites, inorganic-organic hybrids constitute an important family of open-framework structures. In this thesis, results of investigations of a variety of open-framework metal phosphates, metal phosphites, as well as a new family of phosphite-oxalates are presented. More importantly, studies directed towards the synthesis and understanding of the magnetic properties of various transition metal phosphates, phosphites, phosphite-oxalates and the upconversion behavior of uranium phosphites are discussed at length. In Chapter 1 of the thesis an overview of inorganic open-framework materials is presented. In Chapter 2 and 3, the synthesis, structure of open-framework zinc (Part A of both Chapters) and synthesis, structure and magnetic properties of open-framework iron (Part B of both Chapters) are presented. Some of these compounds show unusual structure and interesting properties. For example, two-dimensional iron phosphate exhibits ferrimagnetism whereas three-dimensional iron phosphate with SBU-6 and SBU-2 is antiferromagnetic. The three-dimensional iron phosphite exhibits small polarization at low field. In Chapter 4, we present a new family of organically templated hybrid materials synthesized by partially substituting the phosphite by the oxalate ion in manganese, iron and cobalt phosphites. These exhibit a wide range of structures in which the oxalates play an unusual dual role. Some of these compounds show interesting magnetic properties. For example, manganese phosphite-oxalate shows magnetic polarizations on application of high field at low temperatures and iron phosphite-oxalate exhibit ferromagnetism at very low temperature. While a large number of organically templated transition and main-group element phosphites have been synthesized, research on lanthanide and actinide phosphites has been rare. Most of the reported open-framework phosphate and phosphite compounds of uranium possess uranium in +6 oxidation state. The possibility of building open architectures of uranium phosphites has been explored in Chapter 5. The results have been rewarding and both layered and three-dimensional structures have been prepared. Two of them contain uranium in +4 state and exhibit upconversion behavior.

Orientador: Pedro Roberto Furlani / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T17:24:40Z (GMT). No. of bitstreams: 1 Zambrosi_FernandoCesarBachiega_D.pdf: 1814584 bytes, checksum: 7fb7915ab0ca3954ebb3e13c634f3fdf (MD5) Previous issue date: 2010 / Resumo: A restrição ao desenvolvimento das mais variadas culturas agrícolas, devido à deficiência por fósforo (P), é uma condição comum na agricultura brasileira, incluindo a atividade citrícola. Estudos detalhados da nutrição fosfatada podem contribuir para auxiliar no manejo dessas plantas em solos com baixa disponibilidade do nutriente. Desta maneira, foram desenvolvidos quatro experimentos em condições de casa-de-vegetação, utilizando-se como ferramentas: a avaliação da atividade da fosfatase ácida, o fracionamento de P nas folhas, o emprego do radioisótopo 32P para estimativas de absorção e remobilização, medidas de crescimento e eficácia de uso de P, além da avaliação de forma da forma reduzida de P (fosfito, Phi) como fonte do nutriente. Para estes estudos, porta-enxertos cítricos (PE) (limão 'Cravo', citrumelo 'Swingle', tangerinas 'Cleópatra' e 'Sunki', citrange 'Carrizo' e 'Smooth Flat Seville') e combinações copa/porta-enxerto (laranja 'Pêra' sobre tangerina 'Cleópatra' ou limão 'Cravo') foram combinados com variado suprimento e/ou fonte de P. Houve diferenças de crescimento e estado nutricional por P entre os PE, mas todos eles responderam positivamente ao suprimento do nutriente. O limão 'Cravo' foi o PE mais eficiente para a absorção e utilização de P. A atividade da fosfatase ácida nas folhas (AFAF) e nas raízes (AFAR) dos PE foi negativamente correlacionada com os teores de P nesses órgãos. AFAF confirmou a deficiência por P nestas plantas, enquanto que AFAR contribui provavelmente para diferenças na eficiência de absorção de P. As faixas de teores máximos das frações de P nas folhas correspondem à: 1,25-1,32; 0,29-0,50; 0,68-0,83 e 2,5-3,2 g kg-1, para Pi, P-éster, P-ácido nucléico e P-total, respectivamente. A distribuição mais homogênea do fertilizante fosfatado no solo deficiente apresentou potencial para maximizar a absorção do nutriente e respostas de crescimento da laranjeira 'Pêra' enxertada sobre tangerina 'Cleópatra' ou limão 'Cravo'. A planta 'Pêra'/'Cravo' apresentou maior crescimento vegetativo, incluindo o sistema radicular, além de ter sido mais eficiente para absorção e acúmulo de P do que a combinação 'Pêra'/'Cleópatra'. Por outro lado, esta última combinação apresentou maiores taxas de remobilização do nutriente, sendo mais dependente das reservas internas de P para atender a demanda dos novos fluxos de crescimento. Esta constatação esteve de acordo com a maior AFAF das plantas 'Pêra'/'Cleópatra'. As plantas deficientes por P apresentaram maiores taxas e eficiência de absorção do nutriente após o ressuprimento. Houve alta participação do P remobilizado (média de 92%) nos novos fluxos de crescimento, mesmo com o suprimento adequado do nutriente na solução nutritiva. Embora os teores foliares de P-total dos PE citrange 'Carrizo' e 'Smooth Flat Seville' tenham sido incrementados com o uso de fosfito, isto não resultou em ganhos de biomassa vegetal. Desta maneira, o Phi demonstrou não ser uma fonte de P para plantas cítricas, comprometendo o crescimento, nutrição, eficiência e utilização de nutrientes e a assimilação de CO2 / Abstract: The low phosphorus (P) availability is often a growth-limiting to a number of crops growing in Brazil, including citrus plants. Therefore, we expected that studies about P citrus nutrition could be useful to improve the management of these plants at low-P soils. Therefore, four experiments were carried out under greenhouse conditions. As strategy, acid phosphatase activity, P fractions in the leaves, the rate of P uptake and remobilization using 32P isotopic technique, growth parameters and P use efficiency as well as phosphite (a reduced form of P, Phi) as source of P were evaluated. For these studies, citrus rookstocks varieties (CRV, 'Cleopatra' mandarin, 'Rangpur' lime, 'Sunki' mandarin, 'Swingle' citrumelo, 'Carrizo' citrange and 'Smooth Flat Seville') and scion/rootstocks combinations ('Pêra' sweet Orange on 'Cleopatra' mandarin or 'Rangpur' lime) were seleted and combined with P supply and/or source. There were differences on plant growth and P nutrition of citrus rootstocks. But all of them responded positively to phosphorus supply. The 'Rangpur' lime rootstock showed the highest phosphorus uptake and utilization efficiency. Acid phosphate activity in the leaves was negatively related with P concentration and it comproved severe P deficiency of CRV. Differences in APA in the roots might contribute to variation on phosphorus uptake efficiency among CRV. The maximum values of P fractions in the leaves of CRV corresponded to: 1,25-1,32; 0,29-0,50; 0,68-0,83 and 2,5-3,2 g kg-1, for Pi, Péster, P-acid nucleic and P-total, respectively. More homogenous P fertilizer placement in the soil favored nutrient uptake and growth responses of 'Pêra' on 'Cleopatra' and 'Rangpur'. 'Pêra'/'Rangpur' plants growth more (including root system) and were more efficient in P uptake and meeting P requirements than 'Pêra'/'Cleopatra'. This latter scion/rootstock combination showed higher P remobilization and dependence of stored P pools to meet plant's demand. This result is in agreement with the higher APA in the mature leaves of 'Pêra'/'Cleopatra' than in 'Pêra'/'Rangpur'. The rate and phosphorus uptake efficiency were stimulated by P deficiency, while relative remobilization was reduced after P ressuply. Regardless of P avaibility in the nutrient solution, there was elevated contribution of remobilized P (average 92%) in the new shoot growth. Although the total P foliar concentration of 'Carrizo' citrange and 'Smooth Flat Seville' was increased by phosphite, this did not translate into plant growth. Phosphite use was harmful to plant growth, nutrient utilization efficiency and net gás Exchange. So, the use of phosphite did not meet the P requirements by citrus / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Made available in DSpace on 2017-07-25T19:29:42Z (GMT). No. of bitstreams: 1 Hellen Aparecida Arantes.pdf: 691625 bytes, checksum: a3ecb17b706b52a2674dc29e0a5e82cc (MD5) Previous issue date: 2008-12-15 / The development and grain yield of the crop of wheat are influenced by several factors, among which is the interference caused by pathogens present in crops. Currently, the main tool for controlling these pathogens in crops is the use of constant application of fungicides. However, this practice is causing pathogens resistant to these groups of fungicides used, as well as encouraging the expression of the mutagenic character of these populations. In an attempt to provide more tools to control the diseases of wheat to the farmer, this study aimed to: a) assess the effect of timing of implementation and sources of phosphite and acibenzolar-S-methyl alone and combined with the fungicide pyraclostrobin + epoxiconazole in control the powdery mildew (Blumeria graminis f. sp. tritici) and the leaf rust (Puccinia triticina), b) assess the effect of different rates, sources of phosphite and acibenzolar-S-methyl isolated and associated to the fungicide pyraclostrobin + epoxiconazole in control of the spots brown (Bipolaris sorokiniana) and yellow (Drechslera tritici-repentis); c) and in vitro effect of different concentrations of phosphite and pyraclostrobin + epoxiconazole on the mycelial growth and germination of conidia of Bipolaris sorokiniana. About the control of powdery mildew and rust can be concluded that the phosphites have no effect on these pathogens and do not change their productivity. It is also clear that there is no difference between the different sources of phosphites to control the powdery mildew and leaf rust, which occurs on powdery mildew and leaf rust's only when the phosphite associated with the fungicide is applied. About the control of yellow and brown stains concluded that the dose of 1048 g i.a. ha-1 potassium phosphite reduces the severity of leaf spots and can be used as a tool in the management of leaf spots. In in vitro tests concluded that the phosphites have direct action on Bipolaris sorokiniana. / O desenvolvimento e o rendimento de grãos da cultura do trigo são influenciados por diversos fatores, entre os quais se encontram a interferência causada por patógenos presentes nas lavouras. Atualmente, a principal ferramenta de controle destes patógenos nas lavouras é o uso de constantes aplicações de fungicidas. Contudo, essa prática vem ocasionando resistência destes patógenos aos grupos de fungicidas utilizados, bem como favorecendo a expressão do caráter mutagênico destas populações. Na tentativa de disponibilizar mais uma ferramenta de controle às doenças do trigo ao agricultor, este trabalho objetivou: a) avaliar o efeito de épocas de aplicação e de fontes de fosfito e acibenzolar-S-metil isolados e combinados com o fungicida epoxiconazole + piraclostrobina no controle do oídio (Blumeria graminis f. sp. tritici) e da ferrugem da folha (Puccinia triticina); b) avaliar o efeito de diferentes doses, fontes de fosfito e acibenzolar-S-metil isolados e associados ao fungicida epoxiconazole + piraclostrobina no controle das manchas marrom (Bipolaris sorokiniana) e mancha amarela (Drechslera tritici-repentis); c) e efeito in vitro de diferentes concentrações de fosfito e epoxiconazole + piraclostrobina sobre o crescimento micelial e a germinação de conídios de Bipolaris sorokiniana. Sobre o controle de oídio e ferrugem pode-se constatar que os fosfitos não possuem efeito sobre estes patógenos e não alteram a produtividade. Concluiu-se ainda que não existe diferença entre as diferentes fontes de fosfitos no controle de oídio e ferrugem da folha, que ocorre efeito sobre o oídio e a ferrugem da folha apenas quando o fosfito é aplicado associado ao fungicida. Sobre o controle das manchas amarela e marrom conclui-se que a dose de 1048 g i.a. ha-1 de fosfito potássico reduz a severidade das manchas foliares, podendo ser utilizado como uma ferramenta no manejo das manchas foliares. Nos testes in vitro conclui-se que os fosfitos possuem ação direta sobre Bipolaris sorokiniana.

Design and Development of Carbon-Carbon and Carbon-Heteroatom Bond Forming Reactions” is divided into two sections. Section-A, contains two chapters, describes the catalytic ability of iodine for cross coupling reactions. Section-B, divided into three chapters, presents the azidation of organic scaffolds under oxidative conditions. Section A Chapter 1 presents a C-H functionalization of tetrahydroisoquinolines using iodine as a catalyst under aerobic conditions.1 This methodology employs Cross Dehydrogenative Coupling (CDC) strategy as a key step, which is highly atom economical as it doesn’t require pre-functionalized starting materials.2 Owing to the importance of tetrahydroisoquinoline moiety which is present in the umpteen natural products, considerable attention has been put up to functionalize tetrahydroisoquinoline scaffold.3 Iodine a non-metal which is non-toxic was found to catalyze the C-H functionalization of tetrahydroisoquinolines with a variety of nucleophiles such as coumarin, alkyl phosphite, phenols, indoles, acetone and dialkyl malonoates were coupled to it. Significant mechanistic study has been carried out to find the possible intermediate and support the mechanistic proposal. A few representative examples are highlighted in Scheme 1.1 Synopsis Scheme 1: A CDC coupling of tetrahydroisoquinoline with variety of nucleophiles Chapter 2 describes the Cross Hetero Dehydrogenative Coupling (CHDC) reactions of amines, alcohols and sulfoximines with various phosphites.4 Phosphoramidates and phosphate esters are structural scaffolds that are present in a variety of biologically active molecules.5 The conventional methods for synthesizing phosphoramidates/phosphate esters largely involve treating alcohol/amine with appropriate phosphorus halides which generates stoichiometric amount of halogen waste.6 Due to the usage of stoichiometric reagents and difficulties associated with the reported methods, there is a need for developing a protocol which is catalytic and mild. Therefore, we developed a method which employs catalytic amount of iodine and aq. H2O2 as a sole oxidant under milder conditions. Using this methodology, variety of phosphoramidates, phosphorous triesters and sulfoximine derived Synopsis Scheme 2: Phosphorylation of amines, alcohols and sulfoximines phosphoramidates have been synthesized with great efficiency and environmentally benign conditions. A few representative examples are highlighted in Scheme 2.4 Section B Chapter 1 of Section B demonstrates a mild way of synthesizing quaternary azides from α-substituted active methylene compounds which will serve as surrogates for several unnatural amino acid derivatives.7 Azidation has emerged as one of the efficient methods to introduce nitrogen atom in to the organic molecules.8 Azides are versatile functional groups which can be converted to amine, amide, and nitro compounds by simple modification. Moreover, azides are potential handle for “click” chemistry and provide late stage modifications in drug candidates, biomolecules and polymers, etc.9 Azidation of 1,3-dicarbonyl compounds is challenging, as both azides and 1,3-dicarbonyl compounds are nucleophilic in nature. In this section of the thesis, azidation of 1,3-dicarbonyl compounds has been carried out using tetrabutyl ammonium iodide (TBAI) as a catalyst, aq. TBHP as an oxidant and TMSN3 as a azide source. This method uses water as a solvent under mild reaction conditions to generate Synopsis quaternary azides in good to excellent yields. This operationally simple, practical, mild and green method provides an opportunity for synthesizing a variety of azidated β-keto esters, amides and ketones in good yields, Scheme 3.7 The application of this methodology has been demonstrated by synthesising a few triazole and pyrazolone derivatives. Scheme 3: Azidation of 1,3-dicarbonyl compounds Chapter 2 of Section B comprises the azidation and peroxidation of β-napthol derivatives using dearomatization strategy. Azidation and peroxidation are efficient ways to introduce nitrogen and oxygen into organic molecules, which serve as surrogates for amines and alcohol functional groups. In the present study, the azidative or peroxidative dearomatization of naphthol derivatives have been described. The azidation of β-napthol derivatives has been achieved by using CuBr (5 mol %) as a catalyst, TMSN3 as an azide source and aq. TBHP as an oxidant. Whereas, the peroxidation β-napthol derivatives has been accomplished using CuBr (5 mol %) in the presence of aq. TBHP at ambient reaction conditions.10 The products obtained are naphthalenone derivatives, which serve as valuable Synopsis synthetic intermediates and has potential handle for further functionalization.11 Several α-amino or α-peroxy naphthalenones are synthesized using this method in good yields. The usefulness of the methodology has been illustrated by synthesizing a few chiral azides and peroxides in good yields and with moderate enantioselectivity Scheme 4.10 Scheme 4: Dearomatizative azidation and peroxidation of 2-naphthols Chapter 3 reveals the azidation of indole at C-2 position by employing CuBr (10 mol %) as a catalyst and aq. TBHP as an oxidant in acetonitrile under reflux conditions (Scheme 5).12 The C-H functionalization of indole at C-2 position is one of pivotal methods, since it paves a way for synthesizing a variety of indolo-alkaloids.13 Azide is a versatile functionality which can be converted to several other nitrogen containing functional groups such as Synopsis Scheme 5: Azidation of indoles amine, amide, triazole, etc.9 A variety of functional groups were tolerated under the reaction conditions, and furnished the azidated product in good to excellent yields. Through radical inhibition study, we presume that the reaction may be proceeding through radical mechanism. In Scheme 5, a few representative examples are depicted.

No description available.

A set of five new C3-symmetric phosphites were synthesized and tested in palladium-catalyzed asymmetric Suzuki coupling. The observed reactivity and selectivity were dependent upon several factors. One of the phosphites was able to achieve some of the highest levels of enantioselectivity in asymmetric Suzuki couplings with specific substrates. Different hypotheses have been made for understanding the ligand effects and reaction selectivities, and those hypotheses were tested via various methods including DOSY NMR experiments, X-ray crystallography, and correlation of catalyst selectivity with Tolman cone angles. Although only modest enantioselectivities were observed in most reactions, the ability to synthesis these phosphites in only three steps on gram scales and to readily tune their properties by simple modification of the binaphthyl 2´-substituents makes them promising candidates for determining structure-selectivity relationships in asymmetric transition metal catalysis, in which phosphites have been previously shown to be successful. A series of novel chiral oxazoline-based carbodicarbene ligands was targeted for synthesis. Unfortunately, the chosen synthetic route could not be completed due to unwanted reactivity of the oxazoline ring. However, a new and efficient route for Pd-catalyzed direct amination of aryl halides with oxazoline amine was developed and optimized during these studies. Chiral binaphthyl based Pd(II) ADC complexes with different substituent groups have been synthesized and tested in asymmetric Suzuki coupling reactions. Although only low enantioselectivities were observed in Suzuki coupling, this represents a new class of chiral metal-ADC catalysts that could be tested in further catalytic.