The infrared, Raman and ultraviolet spectra of pyridine-d0 and pyridine-d5 were recorded and assigned with a focus on the low-frequency vibrational modes in the S1(n,pi*) electronic excited state. An energy map for the low-frequency modes was constructed and the data for the v18 mode allowed a highly anharmonic one-dimensional potential energy function to be determined for the S1 excited state. In this S1(n,pi*) state, pyridine is quasi-planar and very floppy with a barrier to planarity of 3 cm^-1. The infrared, Raman and ultraviolet spectra of 2-fluoropyridine (2FPy) and 3-fluoropyridine (3FPy) have been collected and assigned. For 2FPy about 150 bands were observed for the transitions to the vibronic levels of the S(pi, pi*) state at 38,030.4 cm^-1. For 3FPy more than a hundred absorption bands associated with the S(n,pi*) state at 35,051.7 cm^-1 and about forty broad bands associated with the S(pi, pi*) state at 37,339 cm^-1 were observed. The experimental work was complemented by ab initio calculations and these also provided calculated structures for 2FPy, 3FPy, and pyridine. They showed that the fluorine atom on the ring participates in the pi bonding. The gas-phase Raman spectra of 1,3-butadiene and its 2,3-d2, 1,1,4,4-d4, and d6 isotopomers have been recorded with high sensitivity in the region below 350 cm-1, in order to investigate the internal rotation (torsional) vibration. The data for all the isotopomers were then fit using a one-dimensional potential energy function of the form V = (1/2)Sigma(Vn(1-cos (phi))). The energy difference between trans and gauche forms was determined to be about 1030 cm^-1 (2.94 kcal/mol), and the barrier between the two equivalent gauche forms to be about 180 cm^-1 (0.51 kcal/mol), which agrees well with high-level ab initio calculations. The results from an alternative set of assignments also fits the data quite well are also presented. Combination and hot band series involving the v13 torsional vibration of the trans rotamer were observed for each of the butadiene isotopomers. In addition, the high signal to noise of the Raman spectra made it possible to detect several dozen bands of the gauche rotor which makes up only about 2% of the molecules at ambient temperature.

Deux sujets indépendants ont été traités dans ce manuscrit.Dans une première partie a été étudiée la possibilité d'obtenir des synthons chiraux à partir de la pyridine. Pour cela nous avons dans un premier temps développé une méthode originale de quaternisation des sels de pyridium et d'imidazoliums grâce à une réaction de Mitsonubu. Par la suite, des 2-aminopyridines ont été substituées puis engagées dans une réaction de quaternisation-réduction conduisant à des composants saturés. Malheureusement, des composés n'ont pu conduire aux synthons linéaires envisagés.Dans une seconde partie, nous nous sommes intéressés au développement d'un nouveau type de peptidomimétique dans lequel le lien amide est remplacé par un cycle imidazolique, ceci dans la continuité de travaux menés dans notre équipe. Dans un premier temps, nous nous sommes focalisés sur la mise au point de conditions efficaces menant au mime considéré. Cette méthodologie nous a permis la synthèse de plusieurs dipeptides.

The development of novel selective 5-HT6 and 5-HT7 receptor antagonists is an ever-growing area of interest among medicinal chemists. The potential of developing a therapeutic agent useful as an antipsychotic or antidepressant, as well as the possibility to develop a drug for Alzheimer’s disease and obesity has led to an increase in synthesis of possible lead compounds. The synthesis of unfused biheteroaryl derivatives is described within. The derivatives have been evaluated for binding affinity at 5-HT2A, 5-HT6 and 5-HT7 receptors. The most potent 5-HT6 receptor antagonists include a benzene ring, a hydrophobic group and a protonated nitrogen atom. The most potent and selective compound synthesized is 1-[3-butyl-5-(thienyl)phenyl]-4-methylpiperazine. The binding site of the 5-HT7 receptor is similar to that of the 5-HT6 receptor and the most selective and potent 5-HT7 receptor antagonist also contains a potonated nitrogen atom and a hydrophobic group. The difference in selectivity between the 5-HT6 and 5-HT7 receptor antagonists is the aromatic ring. The most potent 5-HT7 receptor antagonist synthesized contains a pyridine ring instead of benzene, as in the 5-HT6 receptor antagonist. The most potent and selective 5-HT7 receptor antagonist is 1-[4-(3-furyl)-6-methylpyridin-2-yl]-4-methylpiperazine. The need to increase selectivity for both 5-HT6 and 5-HT7 receptors has led to the synthesis of flexible-chain linked derivatives and the results are described within.

19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2515" Roman Vladimirovich Rozhkov. 12/19/2004. Report is also available in paper and microfiche from NTIS.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 10, 2010). Includes bibliographical references. Also issued in print.

xx, 214 p. : ill. (some col.) / Intramolecular cascading Michael additions have the ability to transform simple, symmetric substrates into densely functionalized compounds containing new ring structures and chiral centers. The Rauhut-Currier (RC) reaction, also known as the vinylogous Morita-Baylis-Hillman reaction, utilizes this type of reactivity by cyclizing tethered, activated alkenes using phosphine or thiolate catalysis. This dissertation describes the expansion of the scope of the RC reaction, the introduction and importance of co-catalysts to cascading Michael additions, the development of the first amine-catalyzed RC reaction, and the transformation of cyclization products into fused, polycyclic aromatic compounds. Chapter I reviews the development and applications of the Rauhut-Currier reaction. Chapter II describes the regioselective synthesis of di-substituted indenes and introduces phenol as a rate- and selectivity-enhancing co-catalyst. Although tertiary amine nucleophiles were found to be inferior to phosphines as cyclization catalysts, chapter III discusses the ability of unhindered primary and secondary amines to undergo a diastereoselective, cascading aza-Michael-Michael addition to yield a wide variety of amino-indanes in the presence of an acid catalyst. Recognizing the importance of protic environments and small nucleophiles, the development of the first amine-catalyzed intramolecular RC is introduced in chapter IV. Chapter V describes the conversion of methyl ketone-substituted indenes to fluorene derivatives via an intramolecular aldol reaction. Chapter VI describes the serendipitous discovery and synthesis of indenopyrylium salts. Chapter VII details the novel production of indenopyridines from di-substituted indenes. Lastly, chapter VIII provides a summary and suggests future directions for this research. This dissertation includes previously published and unpublished co-authored material. / Committee in charge: Shih-Yuan Liu, Chairperson; Kenneth Doxsee, Advisor; David Tyler, Member; Michael Haley, Member; A. Dana Johnston, Outside Member

La loi du 6 juin 2006 sur la gestion des déchets radioactifs de haute activité et à vie longue prévoit la recherche de solutions permettant la séparation et la transmutation des radioéléments à vie longue, pour réduire les quantités et la nocivité des déchets radioactifs ultimes. Ces déchets issus du retraitement du combustible nucléaire usé sont actuellement vitrifiés à La Hague. Ainsi, le projet « séparation poussée » vise à compléter le procédé industriel PUREX par le développement de procédés permettant d’extraire les actinides mineurs des raffinats PUREX où se trouvent également des produits de fission constitués principalement de lanthanides, neutrophages. Pour réaliser la séparation poussée, les actinides mineurs des raffinats PUREX doivent être séparés par des molécules spécifiques. Les BTP ou bis-triazinyl-pyridines ont été largement étudiées au CEA pour la séparation actinides(III)/lanthanides(III). Elles complexent sélectivement les actinides, mais l'origine de cette sélectivité n'est pas complètement expliquée : notamment l’influence des groupements (attachés à leur structure) sur la complexation ou la sélectivité reste à démontrer. En outre, elles sont sensibles à l'hydrolyse et à la radiolyse. La première partie du travail présente la synthèse de BTP ou de BTBP, différemment substituées pour améliorer leur résistance face à l'hydrolyse ou à la radiolyse, et une nouvelle famille de ligands polyaromatiques azotés : les BPBT, présentant un enchaînement original de cycles pyridine et triazine, différent de toutes les structures décrites jusqu'à présent dans la littérature. La seconde partie de ce travail est consacrée à l’étude physico-chimique de nouvelles molécules obtenues, en déterminant leurs constantes de protonation et de complexation, pour connaître l’influence des différents groupements sur la complexation et la sélectivité. Enfin, le troisième volet concerne l’étude des propriétés de ces ligands en extraction liquide-liquide, utilisés soit comme extractants lipophiles, soit comme complexants hydrophiles. / In France, the nuclear waste issued from the industrial reprocessing of spent nuclear fuels (by the PUREX process) are currently vitrified at the La Hague plant, waiting for a final disposal in a deep geological repository. The law voted in June 2006 on the management of highly active nuclear waste plans to look for solutions enabling the separation and transmutation of long-lived radionuclides so as to reduce the quantity and noxiousness of the final nuclear waste. To address this issue, the CEA investigates and elaborates advanced separation processes based on specially designed complexing or extracting molecules to selectively extract minor actinides from PUREX raffinates containing fission products like lanthanides, which are neutron scavengers. BTP or bis-triazinyl-pyridines have been extensively studied at the CEA (and in Europe) for actinides(III)/lanthanides(III) separation. They complex actinides(III) selectively. However, they are sensitive to degradation by hydrolysis and radiolysis. Besides, their separation mechanisms are not well understood, especially the influence of their substituting groups on their complexing and extracting properties. The first part of work reports the syntheses of various BTP and BTBP molecules, differently substituted, as well as a new family of polyaromatic nitrogen-contained ligands: BPBT, presenting a pyridine/triazine sequence that has never been reported in the literature. The second part is devoted to the physico-chemistry studies of the synthesized molecules, such as the determination of their protonation and complexation constants to describe the influence of different substituting groups. Finally, the last part outlines solvent extraction studies by using these ligands either like extractants or like compexants.

São estudados por espectroscopia Raman e infravermelho os complexos de prata (I) com ligantes orgânicos monodentados do tipo [Ag(L)2]NO3 (L= piridina, piridina-d5,2,4-dimetilpiridina e 2,6-dimetilpiridina) e [Ag(py)2]ClO4. Com o objetivo de investigar os deslocamentos de algumas frequências dos ligantes quando os complexos são formados, obtivemos os espectros no estado sólido e, em alguns complexos, em solução do ligante. É revista a atribuição das freqüências dos ligantes e, com base a esta, é apresentada uma tentativa de atribuição para os complexos acima citados. Os deslocamentos observados nos espectros dos complexos de prata (I) com piridina têm a mesma ordem de grandeza dos obtidos nos correspondentes complexos de metais de transição, porém diferentes dos obtidos por outros autores nos compostos de boro com piridina. Observa-se que os deslocamentos são devidos não só à complexação mas, principalmente, à mudança de estado. A análise dos espectros indicam bem que as bandas deslocadas da piridina e da 2,4-dimetilpiridina, nos complexos, podem ser atribuídas às vibrações de deformação do anel do plano e fora do plano, respiração do anel e deformação C-H no plano. / The complexes of silver (I) with monodentates organic ligands of the type [Ag(L)2]NO3 (L= pyridine, pyridine-d5, 2,4-dimetylpyridine and 2,6-dimetylpyridine) and [Ag(py)2]Clo4 are studied by Ramanand infrared spectroscopy. In order to investigate the displacement of some frequencies of the ligands when the complexes are formed, the spectra were obtained in the solid state and, in some complexes, in solution of the ligand. Previous assignments of the ligand frequencies are reviewed and, based on this, a tentative assignments for the above complexes is presented. The observed displacement in the spectra of the complex of silver (I) with pyridine have the same order of magnitude as those obtained in the correspondent transition metals complexes but different from those obtained by other authors in boron compounds with pyridine. It is observed that displacements are not due only to complexation but mainly due to the change of physical state. The analysis of the spectra shows that the changes in the pyridine and 2,4-dimetylpyridine bands in the complexes can be assigned to the in plane and out-of-plane ring deformation, to the ring breathing vibration and to the C-H in plane deformation.

This work was initially launched to study the synthesis of low-valent group 13 compounds bearing the bis(imino)pyridine ligand framework. Since its inception, this project has grown beyond the boundaries of group 13 to include low valent tin, silver, and rhenium. Alongside the reports of novel coordination compounds, we utilized computational chemistry to uncover unprecedented interactions which challenge conventional concepts of bonding. Synthesis, characterization, and complimentary computational studies are presented herein. Chapter 1 presents a historical overview of the bis(imino)pyridine ligand as well as our synthetic methodology and characterization of new ligand variants we have contributed to the literature. Chapter 2 presents the synthesis of a series of In(I) and In(III) bis(imino)pyridine complexes with varied sterics. Ligand-metal interaction and effect of ligand steric bulk on complex stability, as well as computational studies highlighting weak covalent interactions will be discussed. Chapter 3 presents the synthesis of Ga(III) bis(imino)pyridine complexes. Reactivity with “GaI” synthon as well as varied-stoichiometry one-pot synthesis attempts to generate low valent Ga-bis(imino)pyridine complexes will be discussed. Chapter 4 presents the synthesis of a series of Tl(I) bis(imino)pyridine complexes with varied sterics analogous to the approach taken with indium(I). Unprecedented weak ligand-metal as well as Tl-arene interactions will be discussed. Chapter 5 presents the synthesis of a series of Sn(II) bis(imino)pyridine complexes with varied sterics and halide substituents. Preferential cation-anion pair formation and attempted reactivity will be discussed. Chapter 6 presents the synthesis of a series of Ag(I) bis(imino)pyridine complexes with varied sterics. Resulting ligand-metal interactions as well as reactivity towards Lewis basic donor ligands will be discussed. Chapter 7 presents the synthesis of first crystallographically authenticated examples of rhenium(I) pincer complexes utilizing the bis(imino)pyridine ligand. Chapter 8 presents a general conclusion to the work.

Dans une première partie, la protection des phénols et des pyridinols a été étudiée. Une nouvelle méthode de tetrahydropyranylation a été développée via la réaction de Mitsunobu. Les pyridinols et des phénols ont ainsi été protégés sous forme d'acétal. Cette méthode est sélective d'un phénol vis-à-vis d'un alcool ou d'une amine. La métallation régiosélective des pyridinols 3- et 4- OTHP a été ensuite réalisée. La fonctionnalisation de ces composés, via des réactions successives de métallation et une hydrolyse acide, a permis la synthèse de pyridinols difonctionnalisés "one-pot". Dans le but d'étudier le pouvoir ortho-directeur du groupe O-THP lors de la réaction de métallation, des essais de déprotonations compétitives ont été réalisés avec un pyridinol protégé par un OMe ou une carbamate. Dans une seconde partie, nous avons étudié une synthèse courte et efficace de la (-)-lentiginosine et de ses épimères à partir de la 2-bromopyridine avec de bons rendements. Nous avons synthétisé la (-)-lentiginosine et deux de ses épimères avec de bons rendements. Au cours de cette synthèse, nous avons développé une nouvelle méthodologie de quaternarisation de pyridine via la réaction de Mitsunobu. / We report that the tetrahydropyranylation of pyridinols and phenols, exhibiting especially very low nucleophilicities, can be achieved by means of Mitsunobu reaction with 2-hydroxy-tetrahydropyran. We studied the regioselective deprotonation of 3- an 4-(tetrahdropyran-2-yloxy)pyridines with n-butyllithium. Trapping the lithiated species with various electrophiles afforded functionalized pyridines in good yields. A one-pot procedure also allowed the double fuctionalization at C4 and C2 in the case of 3-O-THP-pyridine. The ortho-metallating ability of this group was examined in comparison with other well-known oxygen-based ortho-directing groups. A four-step synthesis of (-)-lentiginosine and its epimers is described starting from 2-bromopyridine. The key step consisted of a quaternarization of a fully unprotected pyridinium-polyol unit using Mitsunobu methodology. We have demonstrated that the Mitsunobu reaction is viable as a new methodology for the N-alkylation of pyridine and for the formation of bridgehead azabicyclic compounds from pyridine derivatives