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Applications of zirconium chemistry to organic synthesisTuckett, Mark William January 1999 (has links)
No description available.
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Reação de β-dimetilaminovinil cetonas com hidroxilamina: regioquímica de formação de 4,5-diidroisoxazóis e de isoxazóis / Regiochemistry study of the isoxazole formation from the reaction of β-dimethylaminovinyl ketones and hydroxylamineRosa, Fernanda Andreia 28 July 2005 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The regiochemistry study of the formation of a series of aryl-, heteraryl- and haloalkyl-substituted isoxazoles from the reaction of β-dimethylaminovinyl ketones and
hydroxylamine is reported. The precursors β-imethylaminovinyl ketones were obtained from the condensation reaction of N,N-dimethylformamide dimethyl acetal and the substituted ketones [R-C(O)-CH3, where R = Ph, MeO-4-C6H4, Me-4-C6H4, F-4-C6H4, Cl- 4-C6H4, Br-4-C6H4, O2N-4-C6H4, Fur-2-yl, Tien-2-yl, Pyrrol-2-yl, Pyrid-2-yl, and CCl3]. The study shown that for R = trichloromethyl substituent was obtained regiospecifically 5-halomethyl-4,5-dihydroisoxazoles. For precursors with R = O2N-4-C6H4, Fur-2-yl were obtained 3-aryl-4,5-dihydroisoxazole, for R = MeO-4-C6H4, F-4-C6H4, Br-4-C6H4, Pyrrol-2-yl were obtained 5-aryl[heteroaryl]isoxazoles, and for remainder substituents (R = Ph, Me-4-C6H4, Cl-4-C6H4, Tien-2-yl, Pyrid-2-yl) were obtained a mixture of the 4,5-dihydroisoxazoles-1,3 and isoxazoles-1,5. The effect of the substituent on the regiochemistry of isoxazoles obtained was discussed with bases on a MO calculations data. / Este trabalho descreve o estudo da regioquímica de formação de uma série de isoxazóis aril-, heteroaril- e haloalquil substituídos, a partir da reação de β- dimetilaminovinil cetonas e hidroxilamina. O precursor β-dimetilaminovinil cetona foi obtido a partir da reação de condensação de N,N-dimetilformamida dimetil acetal e a cetona substituída [R-C(O)-CH3, onde R = Ph, MeO-4-C6H4, Me-4-C6H4, F-4-C6H4, Cl-4-C6H4, Br-4-C6H4, O2N-4-C6H4, Fur-2-il, Tien-2-il, Pirrol-2-il, Pirid-2-il, e CCl3]. O estudo mostrou que para R = triclorometil substituinte foi obtido regioespecificamente 5-halometil-4,5-diidroisoxazóis. Para precursores com R = O2N-4-C6H4, Fur-2-il foram obtidos 3-aril-4,5-diidroisoxazóis, para R = MeO-4-C6H4, F-4-C6H4, Br-4-C6H4, Pirrol-2-il foram obtidos 5-aril[heteroaril]isoxazóis, e para os demais substituintes (R = Ph, MeO-4- C6H4, Cl-4-C6H4, Tien-2-il, Pirid-2-il) foram obtidos uma mistura de 4,5-diidroisoxazóis-1,3 e isoxazóis-1,5. O efeito do substituinte na regioquímica dos isoxazóis obtidos foi
discutido com base nos dados de cálculos de orbitais moleculares (AM1).
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Heterociclização entre 4-alcóxi-1,1,1-triflúor-3-alquen-2-onas e hidrazonas: metodologias seletivas para a obtenção de heterociclos trifluormetilados / Heterocyclization of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones with hydrazones: selective methods for the synthesis of trifluoromethylated heterocyclesAmaral, Simone Schneider 01 July 2009 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Several methods for the regioselective synthesis of trifluoromethylated heterocycles from 4-alcoxy-1,1,1-trifluoro-3-alken-2-ones and hydrazones are described. In the first part of this work, a series of (E)-2-[N -benzyl(1-phenylethyl)idenehydrazino]-4-trifluoromethyl-pyrimidines were obtained in a convergent manner from the cyclocondensation reaction between Nguanidinobenzylimines and 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones in excellent yields (68-99%). Most reactions were highly diastereoselective and the benzyliminic bound presented preferably the E configuration which was determined by single-crystal X-ray analysis of two diastereoisomeric pure benzylidenepyrimidines derivatives. Afterwards, the synthetic versatility of these pyrimidines was demonstrated through the synthesis of 2-(N -enzylhydrazino)-4-trifluoromethyl-pyrimidines and 3-aryl-7-trifluoromethyl[1,2,4]triazolo[4,3- a]pyrimidines. The synthesis of benzylhydrazinopyrimidines were achieved from
the selective reduction of the benzyliminic moiety of the benzylidenepyrimidines employing NaBH3CN as reduction agent in an acidic media (pH 3-5). Yields were in the 33-74% range. The 1,2,4-triazolo[4,3-a]pyrimidines were isolated after oxidative heterocyclisation promoted by a copper II catalyst. Those reactions proceeded under mild conditions (DMF, 1.5h, 50-90 °C), were highly chemoselective and yields from 33 and 70%. In the second part of this work, the synthesis of 1-phenyl-3-trifluoromethyl-1H-pyrazoles from 4-alkoxyvinyl trifluoromethyl ketones and phenylhydrazine hydrazones are reported. Those heterocyclisations were highly
selective, presented good yields (40-93%) and furnished a series of new enaminones as reaction intermediates. Those reactions that furnished a mixture isomeric pyrazoles, the major isomer was easily isolated through column
chromatography. / Esta tese descreve diversas metodologias para a síntese regiosseletiva de heterociclos trifluormetilados a partir de 4-alcóxi-1,1,1-triflúor-3-alquen-2-onas e hidrazonas.
Na primeira parte do trabalho, uma série de (E)-2-[N -benzil(1-feniletil) idenohidrazino]-4-trifluormetilpirimidinas inéditas foi obtida de maneira convergente a partir da ciclocondensação entre N-guanidinobenziliminas e 4-alcóxi-1,1,1-triflúor-3-alquen-2-onas em ótimos rendimentos (68-99%). A maior
parte das reações foram altamente diastereosseletivas e a configuração E da ligação benzilimínica foi considerada preferencial após análise por difração de raios X dos monocristais de duas benzilidenopirimidinas
diastereoisomericamente puras. Posteriormente, a versatilidade sintética desses heterociclos foi demonstrada através da obtenção das 2-(N - benzilhidrazino)-4-trifluormetilpirimidinas e das 3-aril-7- trifluormetil[1,2,4]triazolo[4,3-a]pirimidinas. As benzilhidrazinopirimidinas foram
obtidas a partir da redução seletiva do grupo benzilimínico das
benzilidenopirimidinas empregando NaBH3CN como agente redutor em meio ácido (pH 3-5) com rendimentos que variaram entre 33-74%. As 1,2,4-triazolo[4,3-a]pirimidinas, por sua vez, foram sintetizadas a partir do mesmo
precursor através de heterociclização oxidativa mediada por cloreto de cobre II. Essas reações empregaram condições reacionais relativamente brandas (DMF, 1,5h, 50-90 °C), foram altamente quimiosseletivas e apresentaram rendimentos
entre 33-70%. Na segunda parte deste estudo, a síntese de 1-fenil-3-trifluormetil-1Hpirazóis a partir das 4-alcoxivinil-trifluormetil cetonas e das hidrazonas derivadas da fenilhidrazina foi descrita. Essas heterociclizações foram
altamente seletivas, apresentaram bons rendimentos (40-93%) e ainda possibilitaram a obtenção de uma série de enaminonas inéditas como intermediários reacionais. Nas reações em que foram obtidas misturas de pirazóis isoméricos, os isômeros majoritários desejados foram isolados por
cromatografia em coluna.
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Multiple functionalization of C60 hexa-adducts by « click » chemistry / Fonctionnalisation multiple d’hexa-adduits du C60 par chimie « click »Schillinger, Franck 29 September 2016 (has links)
Dans un premier temps, la bis- et tris-fonctionnalisation du C60 a été effectuée par une approche macrocyclique. Différents bis- et tris-adduits du C60 ont été obtenus avec de bonnes régioselectivités. Dans un deuxième temps, la tris-fonctionnalisation du C60 a été effectuée par une approche « tête directrice ». Par cette approche, un accès rapide, simple, régio- et stéréo-sélectif à des tris-adduits e,e,e approprié à la formation d’hexa-adduits d’ordre d’addition octaédrique a été obtenu. La synthèse et la séparation de tris-adduits e,e,e optiquement purs ont également été réalisées. Les dérivés polyols obtenus par déprotection des groupes silylés ouvrent de nouvelles perspectives pour la post-fonctionnalisation de multi-adduits de C60. A partir de nos méthodologies de synthèse de bis- et tris-adduits de C60, des synthons d’hexa-adduits mixtes de C60 ont été préparés. La post-fonctionnalisation de ces synthons a été effectuée par réaction de cycloaddition1,3-dipolaire de type Huisgen mais aussi par réaction d’estérification, afin d’obtenir des hexa-adduitsde C60 multifonctionnels. La méthodologie de synthèse d’hexa-adduits de C60 multifonctionnels aété mise à profit pour l’élaboration d’édifices hyperfonctionnels comportant plusieurs hexa-adduits de C60 autour d’un hexa-adduit de C60 central. La post-fonctionnalisation des synthons hexa-adduits mixtes par chimie « click » donne accès à la préparation contrôlée de nouveaux nanomatériaux globulaires multifonctionnels. / In a first instance, the bis- and tris-functionalization of C60 was performed by a macrocyclic approach. Different bis- and tris-adducts of C60 were obtained with good regioselectivity. In a second instance, the tris-functionalization of C60 was performed by a “tether-directed” approach. By this approach, a fast, simple, regio- and stereoselective access to C60 e,e,e tris-adduct suitable for the formation of C60 hexa-adducts with an octahedral addition pattern was obtained. The synthesis and the separation of optically pure e,e,e tris-adducts was also realized. The polyol derivatives obtained by deprotection of the silyl groups open new perspectives for the post-functionalization of C60 multiadducts. Using our synthesis methodologies of bis- and tris-adducts of C60, mixed hexa-adducts building blocks were prepared. The post-functionalization of these building blocks was carried out by copper catalyzed azide-alkyne 1,3-dipolar cycloadditions but also by esterification reactions to obtain multifunctional C60 hexa-adducts. The methodology for the synthesis of multifunctional C60 hexa-adducts was used for the elaboration of fullerodendrimers containing several C60 hexa-adducts around a central C60 hexa-adduct. The post-functionalization of the mixed hexa-adducts building blocks by “click” chemistry gave access to the controlled preparation of new globular and multifunctional nanomaterials.
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