The work in this thesis has demonstrated the chiral recognition through the adaptation of chromatographically derived chiral recognition systems by electrospray ionization mass spectrometry (ESI-MS). Mass-labeled, pseudoenantiomeric chiral selectors (where each pseudoenantiomer had the opposite stereochemistry, but was slightly different in mass due to labeling of one enantiomer) were prepared as soluble analogues of Pirkle type chiral stationary phases. When mixed with a chiral analyte, solutions containing these pseudoenantiomeric selectors afforded selector-analyte complexes in the ESI-MS, and the relative peak intensities of the complexes could be related back to the enantiomeric composition of the analyte. In each case of this study, the complex intensity fraction for either of the selector-analyte complexes in the ESI-MS varies linearly with the enantiomeric composition of the analyte. This linear relationship provides a measure of the extent of enantioselectivity and allows quantitative analysis of the enantiomeric composition of analyte.

Memory of chirality (MOC) is an emerging strategy in asymmetric synthesis. It has been applied to enolate chemistry, reactions involving carbocation intermediates, and to radical systems. In this strategy the chirality of an enantiopure reactant is transferred to the dynamic chirality of a reactive intermediate to produce stereospecific product. 1,4-Benzodiazepin-2-ones have been described as a "privileged" structure in medicinal chemistry. In addition to their uses as anxiolytics (Valium ®) and anti-epileptic agents (Clonopin ®), they have shown activity as HIV Tat antagonist, ras farnesyltransferase inhibitors in cancer cells, and antiarrhythmic agents. Because of the utility of this scaffold in the area of medicinal chemistry, it has served as a template in libraries for tens of thousands of compounds. Despite the vast diversity of 1,4-benzodiazepin-2-ones, there are few routes to enantiomerically enriched 3,3-disubstituted benzodiazepines containing a "quaternary" stereogenic center. This research will discuss the stereochemical properties of 1,4-benzodiazepin-2-ones, and provide a novel approach to synthesize enantiomerically enriched "quaternary" benzodiazepines with stereogenic centers through MOC, without the use of external chiral sources. / Ph. D.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O Brasil à o maior produtor mundial de laranja e de suco de laranja, sendo este setor de grande importÃncia para economia brasileira, responsÃvel por gerar mais de 400 mil empregos e movimentar cifras de bilhÃes de reais por ano. Mas, este setor tambÃm à responsÃvel pela produÃÃo de grande quantidade de rejeitos industriais, que equivalem a 50% do peso da fruta, sendo estes resÃduos utilizados na maioria das vezes como raÃÃo animal. Portanto o uso eficiente destes rejeitos se faz necessÃrio em um mundo em que as reservas naturais vÃm se esgotando. Neste sentido a biocatÃlise mostra-se como uma ferramenta promissora no uso destes resÃduos, que possuem enzimas em sua constituiÃÃo, para obtenÃÃo de produtos de alto valor agregado, as substÃncias enantiopuras. A aplicaÃÃo de diferentes metodologias, prÃticas e de baixo custo, possibilitou a sÃntese de alcoÃis quirais com alto excesso enantiomÃrico (ee) e boas taxas de conversÃo. ReaÃÃes de hidrÃlise e reduÃÃo foram processadas em meio aquoso e, as reaÃÃes de esterificaÃÃo foram realizadas em solvente orgÃnico, utilizando as casca da laranja como fonte de biocatalisadores. O uso das cascas da laranja como fonte de biocatalisador apresentou resultados bastante promissores, demonstrando capacidade catalÃtica em vÃrias reaÃÃes (reduÃÃo/oxidaÃÃo, hidrÃlise/esterificaÃÃo) atravÃs de metodologias simples e de baixo custo. ConversÃes de 46,90-96,70% foram alcanÃadas nas reaÃÃes de biorreduÃÃo acompanhado de ee variando de 21,15-99,00%. Nas reaÃÃes de hidrÃlise verificaram-se taxas de conversÃes de 19,20-80,82% e ee variando de 9,60-45,52%. Jà nas reaÃÃes de esterificaÃÃo, ee acima de 99% foram observados e conversÃes maiores que 80% foram alcanÃadas. Portanto, este estudo abre precedentes para uma ampla faixa de aplicaÃÃo desta fonte de biocatalisador (cascas da laranja), que atualmente à considerado como um rejeito industrial, contribuindo sobremaneira para agregar valor a todo um setor produtivo e industrial no qual o Brasil à lÃder, a indÃstria de suco de laranja. / The Brazil is the producing greater of world of orange and orange juice, being this sector of great importance for Brazilian, responsible economy for generating 400 thousand jobs and more than and putting into motion ciphers of billions per year. But, this sector also is responsible for the production of great amount of industrial rejetcs, that are equivalent 50% of the weight of the fruit, being these used residues most of the time as animal ration. Therefore the use efficient of these rejetcs if makes necessary in a world where the natural reserves come if depleting. In this direction biocatalysis is presented as a promising tool in the use of these residues, that contains enzymes in its constitution, for attainment of products of high added value, the substances enantiopure. The application of different methodologies, practical and of low cost, made possible the chiral alcohols synthesis with high enantiomeric excess (ee) and good taxes of conversion. Hydrolysis reactions and reduction had been processed in aqueous way e, the reactions of esterification had been carried through in organic solvent, using the rind of the orange as source of biocatalysis for such reactions. The use of the peel of the orange as biocatalysis source presented resulted sufficiently promising, demonstrating catalytic capacity in some reactions (reduction/oxidation, hydrolysis/esterification) through simple methodologies and of low cost. Conversions of 46,90-96,70% had been reached in the reactions of bioreduction shown of ee varying of 21,15-99,00%. In the hydrolysis reactions taxes of 19,20-80,82% conversions and ee had been verified varying of 9,60-45,52%. Already in the esterification reactions, ee above of 99% had been observed and bigger conversions that 80% had been reached. From there, this study it opens precedents for an ample band of application of this source of biocatalysis (pells of the orange), that currently it is considered as one reject industrial, contributing excessively to add value all a productive and industrial sector in which Brazil is leader, the orange juice industry

<p>Three chiral selectors (diketogulonic acid, benzoxycarbonylglycylproline and ketopinic acid) have been introduced for enantioseparation of pharmacologically active amines in non-aqueous capillary electrophoresis. The use of organic solvents, instead of aqueous buffers in the background electrolyte facilitated ion-pair formation between the analytes and the chiral selectors. The enantioresolution was strongly affected by the choice of selector and organic solvent but also depended on the other electrolytes. The most important parameter for the enantioresolution, apart from the choice of chiral selector, was the direction and magnitude of the electro-osmosis. Thus, covalently coated capillaries were used to suppress and to reverse this flow. Furthermore, the alkali metal hydroxide added to the background electrolyte had a great influence on the electro-osmosis. Exchanging LiOH for NaOH, was found to decrease the electro-osmotic flow. Interestingly, the flow was altered from cathodic to anodic, with KOH, RbOH or CsOH added to the ethanolic BGE. The occurrence of a reversed electro-osmosis had a great positive effect on the enantioresolution. An appropriate choice of solvent and electrolytes promoted also fast chiral separations, e.g., the enantiomers of isoprenaline were resolved within one minute. </p><p>The capillary electrophoresis systems developed within this work were applied for enantiomeric purity determinations of different pharmaceutical forms of drug products. A detection limit of 0.033 % was achieved for <i>1S,2R</i>-ephedrine, the enantiomeric impurity in Efedrin®, when diketogulonic acid was used as the selector. </p><p>By using the pre-concentration technique, transient isotachophoresis, the peak efficiency was enhanced for the enantiomers of timolol. This facilitated the introduction of a higher concentration of the sample into the capillary electrophoretic system containing ketopinic acid as the selector, and lowered the detection limit from 2.5 % to 0.2 % for the enantiomeric impurity <i>R</i>-timolol compared with injection without transient isotachophoresis.</p><p>The volatility of the non-aqueous media in capillary electrophoresis facilitated the hyphenation to mass spectrometry. The partial filling technique ensured that the selector did not contaminate the mass spectrometer, and the separated enantiomers of e.g., pronethalol were detected in the selector-free zone. </p>

Three chiral selectors (diketogulonic acid, benzoxycarbonylglycylproline and ketopinic acid) have been introduced for enantioseparation of pharmacologically active amines in non-aqueous capillary electrophoresis. The use of organic solvents, instead of aqueous buffers in the background electrolyte facilitated ion-pair formation between the analytes and the chiral selectors. The enantioresolution was strongly affected by the choice of selector and organic solvent but also depended on the other electrolytes. The most important parameter for the enantioresolution, apart from the choice of chiral selector, was the direction and magnitude of the electro-osmosis. Thus, covalently coated capillaries were used to suppress and to reverse this flow. Furthermore, the alkali metal hydroxide added to the background electrolyte had a great influence on the electro-osmosis. Exchanging LiOH for NaOH, was found to decrease the electro-osmotic flow. Interestingly, the flow was altered from cathodic to anodic, with KOH, RbOH or CsOH added to the ethanolic BGE. The occurrence of a reversed electro-osmosis had a great positive effect on the enantioresolution. An appropriate choice of solvent and electrolytes promoted also fast chiral separations, e.g., the enantiomers of isoprenaline were resolved within one minute. The capillary electrophoresis systems developed within this work were applied for enantiomeric purity determinations of different pharmaceutical forms of drug products. A detection limit of 0.033 % was achieved for 1S,2R-ephedrine, the enantiomeric impurity in Efedrin®, when diketogulonic acid was used as the selector. By using the pre-concentration technique, transient isotachophoresis, the peak efficiency was enhanced for the enantiomers of timolol. This facilitated the introduction of a higher concentration of the sample into the capillary electrophoretic system containing ketopinic acid as the selector, and lowered the detection limit from 2.5 % to 0.2 % for the enantiomeric impurity R-timolol compared with injection without transient isotachophoresis. The volatility of the non-aqueous media in capillary electrophoresis facilitated the hyphenation to mass spectrometry. The partial filling technique ensured that the selector did not contaminate the mass spectrometer, and the separated enantiomers of e.g., pronethalol were detected in the selector-free zone.

La présence avérée de produits pharmaceutiques et de soin personnels (PPSP) dans le milieu aquatique est principalement due à leur élimination incomplète dans les stations d’épuration (STEP). Ces molécules sont susceptibles de générer des effets néfastes sur les organismes vivants du milieu naturel. Une évaluation préalable des risques qui peuvent être engendrés par les PPSP est nécessaire pour qu’ils puissent être gérés correctement et sûrement par les principaux acteurs du cycle de l’eau tels que les pouvoirs publics et les grandes entreprises de l’environnement, dont fait partie Veolia. La démarche d’évaluation des risques nécessite d’avoir accès à des données sur les processus de biodégradation des PPSP dans l’environnement. Actuellement, les données disponibles sont qualitatives ou semi-quantitatives en raison de l’absence d’outils de mesure quantitatifs adéquats. L’objectif de ce travail de thèse a ainsi consisté à développer des outils pour quantifier spécifiquement les processus de biodégradation des PPSP in situ à des concentrations environnementales. Deux outils complémentaires ont été sélectionnés pour être évalués : le fractionnement énantiomérique, dans le but de quantifier la biodégradation des PPSP chiraux, et le fractionnement isotopique, limité à celui du chlore, dans le but de mesurer la biodégradation des PPSP chlorés. Pour évaluer ces outils, des analyses d’occurrence sur le terrain et des études cinétiques et mécanistiques en laboratoire ont été réalisées sur cinq molécules modèles : deux produits pharmaceutiques chiraux (un bêtabloquant, le métoprolol et un antidépresseur, la venlafaxine) et trois PPSP chlorés (deux biocides, le triclocarban et le triclosan, et un anti-inflammatoire non stéroïdien, le diclofénac). Nos travaux ont démontré que l’utilisation du fractionnement isotopique du chlore seul est peu adaptée à l’étude quantitative de la biodégradation des PPSP chlorés. Une approche isotopique multiéléments serait plus propice pour quantifier les processus de biodégradation. Par ailleurs, les expériences réalisées ont permis d’approfondir l’état des connaissances sur les voies et mécanismes de biodégradation des PPSP étudiés. La déchloration du triclosan dans les sédiments en aval des STEP a été mise en évidence pour la première fois. Concernant le triclocarban, cette réaction était déjà connue mais les mécanismes réactionnels de déchloration sous-jacents ont été élucidés en milieux aérobie et anaérobie. Les résultats obtenus sur l’outil énantiomérique sont très encourageants. Ils démontrent, à l’aide du métoprolol, l’existence d’une relation linéaire entre biodégradation et variations énantiomériques à la fois en conditions contrôlées et dans les STEP. Le fractionnement énantiomérique constitue donc un bon outil quantitatif de la biodégradation du métoprolol. Des études supplémentaires sont néanmoins nécessaires pour étendre ces résultats à d’autres molécules. D’autre part, l’analyse des concentrations et de la stéréochimie des produits de transformation du métoprolol a confirmé que ce composé se biodégrade stéréosélectivement en métoprolol acide et un mécanisme réactionnel a été proposé pour expliquer ces observations. Les cinétiques associées aux réactions de dégradation des PPSP étudiés doivent être mesurées in situ pour évaluer la capacité du milieu naturel à éliminer ces composés, d’où l’importance de rendre opérationnels les indicateurs quantitatifs étudiés au cours de la thèse. Croisées avec des données d’écotoxicité, les informations quantitatives sur la biodégradation peuvent aider les pouvoirs publics à cibler les PPSP qui nécessitent d’être régulés en priorité. Elles peuvent également aider les opérateurs privés à orienter leurs stratégies de réduction d’émission à la source et l’optimisation des procédés de traitement des eaux afin que ces derniers éliminent en priorité les micropolluants les plus à risque. / The widespread occurrence of pharmaceutical and personal care products (PPCP) in surface waters, due to their incomplete removal in wastewater treatment plants (WWTP), is of concern since these compounds may be harmful to living organisms. Environmental risks associated with the presence of PPCP in aquatic environment have to be evaluated in order to help the main actors involved in the water cycle such as public authorities and environmental companies, including Veolia, to manage them properly. Quantitative and qualitative assessment of in situ biodegradation of PPCP is a major need in the context of risk assessment. Quantitative information remains scarcely available due the lack of appropriate methods. The objective of this work was then to develop tools able to quantify specifically in situ biodegradation of PPCP at trace levels. Two different tools have been selected to be evaluated, namely enantiomeric fractionation dedicated to chiral compounds and isotopic fractionation limited to chlorine-isotope analysis dedicated to chlorinated PPCP. To evaluate these tools, environmental occurrence studies and in vitro mechanistic and kinetic studies were together performed using five probe compounds : two chiral PPCP (a beta-blocker, the metoprolol and an antidepressant, the venlafaxine) and three chlorinated PPCP (two biocides, the triclocarban and the triclosan, and a nonsteroidal anti-inflammatory drug, the diclofenac). These experiments demonstrated that chlorine isotope fractionation can hardly provide quantitative information on in situ biodegradation of chlorinated PPCP. Multi-dimensional isotopic fractionation might be better adapted to quantify biodegradation. Furthermore, through the experiments, new insights on biodegradation pathways and mechanisms of the studied compounds have also been gained. Dechlorination of triclosan within sediment has been evidenced for the first time. Concerning triclocarban, dechlorination of this compound in environment had already been reported in previous studies but aerobic and anaerobic dechlorination mechanisms have been elucidated in the present study. Results obtained on enantiomeric fractionation demonstrated that this tool is very promising. Experiments using metoprolol as probe compound showed existence of a linear relationship between enantiomeric enrichment and the extent of biodegradation both under controlled conditions and within WWTP. Enantiomeric enrichment might then constitute a good indicator of in situ biodegradation of metoprolol. Supplementary studies are needed to extrapolate these results to other micropollutants. In addition, stereoselective degradation of metoprolol in acid metoprolol within WWTP and under controlled conditions has been observed similarly to other studies and one degradation mechanism has been proposed to explain the reaction stereochemistry. In situ kinetics associated with degradation pathways of the studied PPSPs have to be measured to assess the ability of the environment to eliminate these compounds, hence the importance of making operational the quantitative indicators studied in this thesis. Crossed with ecotoxicity data, quantitative information on biodegradation can help public authorities to target PPCPs that need to be regulated first. They can also help private operators to direct their source reduction strategies and their water treatment process optimization so that they eliminate in priority the most risked micropollutants.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este trabalho encontra-se dividido em duas partes: a primeira relacionada à biotransformaÃÃes de compostos orgÃnicos com a espÃcie Vigna unguiculata, e a segunda, relativa à sÃntese enzimÃtica de Ãsteres de cloranfenicol. ReaÃÃes de biorreduÃÃo de cetonas e nitrocompostos com grÃos de Vigna unguiculata (feijÃo de corda). ApÃs realizado um screnning com reduÃÃo de acetofenona variando-se as condiÃÃes reacionais, encontrou-se aquelas que levaram ao melhores resultados de conversÃo e excesso enantiomÃrico. Essas condiÃÃes foram aplicadas para outros 34 susbtratos, entre eles: cetonas alifÃticas e aromÃticas com diferentes substituintes no anel como: nitro, metÃxi, alquila e halogÃnios em vÃrias posiÃÃes, nitrocompostos, &#946;-ceto-Ãsteres, uma cetona &#945;,&#946;-insaturada e benzonitrila. No geral, o resultados obtidos com as biorreduÃÃes podem ser considerados satisfatÃrios, assim como os valores de excesso enantiomÃrico. Na segunda parte, utilizou-se as lipases comerciais: CAL-B, PSL-C(I) e PSL-C Amano, em reaÃÃes de acilaÃÃo do fÃrmaco cloranfenicol, num estudo exaustivo em busca de condiÃÃes Ãtimas de reaÃÃo explorando principalmente a atividade regiosseletiva dessas enzimas. Foram obtidos oito derivados desse fÃrmaco, a depender do agente acilante utilizado, sendo sete destes, monoacilados e um, di-acilado. Como doador acila usou-se diversos Ãsteres vinÃlicos, saturados ou nÃo e com diversos tamanhos de cadeia. ParÃmetros reacionais como: variaÃÃo do solvente, da temperatura, concentraÃÃo do meio e agente acilante foram otimizados para obtenÃÃo desses derivados. Praticamente todos os produtos foram obtidos em elevados percentuais de conversÃo, exceto para aqueles que possuem insaturaÃÃo. Realizou-se ainda um procedimento em escala de bancada utilizando a enzima CAL-B, sendo obtidos resultados bem significativos em todos os casos. Ao final do estudo adotou-se um procedimento de reciclagem desta mesma enzima, onde ficou comprovada sua eficiÃncia no reuso. / This work is divided into two parts: the first related biotransformations of organic compounds with the species Vigna unguiculata, and the second on the enzymatic synthesis of esters of chloramphenicol. Reactions bioreduction of ketones and nitrocompounds with grains of Vigna unguiculata (feijÃo de corda). After performing a reduction of acetophenone with screnning varying the reaction conditions, we found those that led to better results for conversion and enantiomeric excess. These conditions were applied to 34 other susbtratos, including: aliphatic ketones and aromatic ring with different substituents such as nitro, methoxy, and alkyl halide in various positions, nitro, &#946;-keto ester, a ketone &#945;, &#946;-unsaturated and benzonitrile. Overall, the results obtained with the biorreduÃÃes can be considered satisfactory, as well as the enantiomeric excess values. In the second part, we used the commercial lipases: CAL-B, PSL-C (I) and PSL-C Amano in acylation reactions of the drug chloramphenicol, an exhaustive study in search of optimum reaction conditions mainly exploring the activity regioselective these enzymes. Were obtained from eight derivatives of this drug, depending on the acylating agent used, seven of these, and a monoacilados, di-acylated. As acyl donor was used several vinyl esters, saturated or not and with various chain lengths. Reaction parameters such as: variations of the solvent, temperature, concentration of the acylating agent and medium were optimized to obtain these derivatives. Virtually all products were obtained in high percentages of conversion, except for those with unsaturation. It is also carried out in a bench scale procedure using the enzyme CAL-B, and significant results were obtained in all cases. At the end of the study we adopted a procedure for recycling of the same enzyme, which was proven its efficiency in reuse.

Made available in DSpace on 2014-07-29T15:12:46Z (GMT). No. of bitstreams: 1 Dissertacao Jeronimo R de O Neto.pdf: 732547 bytes, checksum: aec94205f1a668baad1af6da00c58d09 (MD5) Previous issue date: 2011-10-07 / Termites are eusocial insects of isoptera order that part in seven families. In this study we analyze the chirality of &#945;-pinene in the defensive secretion that C. cyphergaster (Isoptera, Termitidae, Nasutitermitinae) this compound showed that among the majority of termite volatile. Along with checking the chirality was made a study seeking to correlate the production of each enantiomer, R(+)-&#945;-pinene and S(-)-&#945;-pinene, soil and climate data in dry and wet seasons of year 2002 and 2003. In the statistical data were used some statistical techniques such as Detrended Correspondence Analysis, to predict the model, Analysis of Variance for multiple comparison of means, and Redundancy Analysis to show a correlation matrix by another and that have a preview of the separation of groups. The DCA analysis showed that the model is linear. The analysis of variance for both the original data and for the transformed data showed that the averages do not differ statically at 95%, because they have p>0,05. The analysis of redundancy was not possible to explain the environment by the response matrix, in the 95% level of confidence. There was a production of enantiomeric &#945;-pinene by the C. cyphergaster populations, which can be an important factor to assist in chemotaxonomic studies of these specimens. There is increased production of the (S) enantiomer, but it was not possible to correlate this trend with soil and climatic factors in statistically significant odds. The variation of the enantiomérica composition can be related to factors other than soil and climate, such as ecological factors, genetic, or eusocial. / Os térmitas (cupins) são insetos eusociais da ordem Isoptera que se subdividem em sete famílias. Neste trabalho analisamos a quiralidade do &#945;- pineno presente na secreção defensiva do Constrictotermes cyphergaster (Isoptera, Termitidae, Nasutitermitinae), composto este que se mostrou majoritário entre os voláteis deste térmita. Juntamente com a verificação da quiralidade foi feito um estudo buscando correlacionar a produção de cada enantiômero, R(+)-&#945;-pineno e S(-)-&#945;-pineno, com dados edáfico-climáticos nas estações de seca e de chuva dos anos de 2002 e 2003. No tratamento estatístico dos dados foram usadas algumas técnicas estatísticas tais como análise de correspondência destendenciada, para prever o modelo; análise de variância, para comparação múltipla das médias; análise de redundância, para ter uma visualização da separação dos grupos e para correlacionar variáveis das matrizes resposta e ambiental. A análise destendenciada revelou que linear é o modelo mais apropriado. A análise de variância tanto para os dados originais quanto para os dados transformados mostraram que as médias não se diferenciam estatisticamente ao nível de 95 %, pois apresentam p>0,05. Pelas análises de redundância não foi possível a explicação da matriz resposta pelo ambiente, ao nível de 95 % de confiança. Houve uma produção enantiomérica de &#945;-pineno por parte das populações de C. cyphergaster, que pode ser um fator importante para auxiliar em estudos quimiotaxonômicos desta espécie. Há maior produção do enantiômero (S), porém não foi possível correlacionar esta tendência com fatores edáfico-climáticos dentro de probabilidades estatisticamente significativas. A variação da composição enantiomérica pode estar relacionada a outros fatores que não os edáfico-climáticos, tais como: fatores ecológicos, genéticos e eusociais.

Submitted by Carolina Neves (carolinapon@uefs.br) on 2017-02-17T23:59:52Z No. of bitstreams: 1 Disserta??oJoseneideAlves.pdf: 3612959 bytes, checksum: a4ba8033510286e66a0d4453ad52d71d (MD5) / Made available in DSpace on 2017-02-17T23:59:53Z (GMT). No. of bitstreams: 1 Disserta??oJoseneideAlves.pdf: 3612959 bytes, checksum: a4ba8033510286e66a0d4453ad52d71d (MD5) Previous issue date: 2009-08-31 / The biorreduction has great importance in the production of optically pure substances and is widely used for asymmetric synthesis. Bioconversions occur with high specificity and efficiency because they are catalyzed by enzymes, forming one of the isomers from a pro-chiral substrate. This work had as main objective to evaluate the potential reduction of micro-organisms (yeasts, bacteria and fungi) isolated in the state of Bahia using as carbonyl substrate the acetophenone, analyzing its conversion into alcohol and identifying the enantiomeric excess produced. Strains of Saccharomyces cerevisiae isolated from sugar cane brandy distilleries of Bahia state, rhizobacteria isolated from Arachis pintoi (forage peanut) in southern Bahia and endophytic fungi isolated Hevea brasiliensis. The products were analyzed by gas chromatography coupled to mass spectrometry to verify the conversion of the substrate in alcohol and enantiomeric excess was determined by gas chromatography with chiral stationary phase. Of the 28 microorganisms evaluated 18 acted as biocatalysts. Products of reduction of acetophenone were obtained with yields between 6 and 79% and enantiomeric excess from 41 to 100%. Fungi CDC026, CDC086 and MDF077 converted acetophenone into (R)-alcohol, with ee of 54, 56, and 84%, while the other strains that showed positive results for acetophenone yielded the (S)-alcohol. Whereas 64% of test organisms were able to act as catalysts in the enantioseletive reduction of acetophenone, it was observed that the microbial diversity of the state of Bahia is a source of new catalysts for the production of enantiomeric pure compounds. / A Biorredu??o tem grande import?ncia na produ??o de subst?ncias opticamente puras, sendo amplamente utilizada para s?nteses assim?tricas. As bioconvers?es ocorrem com alta especificidade e efici?ncia por serem catalisadas por enzimas, formando um dos is?meros a partir de um substrato pr?-quiral. O presente trabalho teve como objetivo principal avaliar o potencial redutor dos microrganismos (leveduras, bact?rias e fungos) isolados no territ?rio baiano frente ao substrato carbon?lico acetofenona; verificando a convers?o do substrato (acetofenona) em ?lcool quiral e identificando o excesso enantiom?rico com que as rea??es biocatal?ticas ocorreram. Foram utilizadas culturas de Saccharomyces cerevisiae isoladas em cacha?arias do estado da Bahia, rizobact?rias isoladas no sul da Bahia e fungos endof?ticos. Foi testada a a??o desses microrganismos sobre o substrato acetofenona. Os produtos foram analisados por Cromatografia gasosa acoplada a espetrometria de massa, para verificar a convers?o do substrato em ?lcool; o excesso enantiom?rico foi obtido em cromat?grafo gasoso equipado com coluna quiral obtendo-se separa??o para os is?meros da acetofenona com um excesso enantiom?rico de at? 100%, para a cepa bacteriana I68. Os fungos CDC026 e CDC086 converteram a acetofenona em (R)-?lcool, as demais cepas que apresentaram resultados positivos para aceofenona produziram o (S)-?lcool em excesso. Conclui-se que em geral os microrganismos testados apresentaram boa capacidade de redu??o da acetofenona em experimentos de biotransforma??o, constituindo-se fontes de compostos enantiomericamente puros.

A maioria dos agentes terapêuticos, freqüentemente prescritos, são formulados e comercializados sob a forma racêmica, embora para alguns deles, já tenha sido demonstrado que os efeitos farmacológicos e/ou tóxicos estejam relacionados apenas a um dos enantiômeros. Além disso, é conhecido o fato de que os enantiômeros podem apresentar perfis farmacocinéticos e farmacodinâmicos diferentes. Neste trabalho foram selecionados fármacos que fazem parte de dois grupos importantes no uso clínico. São fármacos freqüentemente prescritos, como os &#946;-bloqueadores (atenolol, metoprolol, pindolol, betaxolol e nadolol) e os antiinflamatórios não-esteróides (ibuprofeno e flurbiprofeno ). Existem na literatura científica várias citações que descrevem o uso da cromatografia líquida de alta eficiência com fases estacionárias quirais (CLAE-FEQ) em estudos farmacológicos, mas não na análise quantitativa dos enantiômeros em preparações farmacêuticas. É conhecido o fato de que o método CLAE-FEQs oferece vantagens sobre as técnicas clássicas de separação e análise de estereoisômeros, especialmente para os enantiômeros. As separações enantioméricas diretas do atenolol, metoprolol, nadolol e betaxolol foram obtidas utilizando-se FEQ Chiralcel OD&#174;. Os enantiômeros do pindolol foram separados com FEQ &#945;-Burke 2&#174; e os do ibuprofeno e do flurbiprofeno com FEQ do tipo WheIk-O 1&#174;. Neste trabalho são apresentados métodos rápidos e sensíveis para determinação estereoespecífica do atenolol (AT), do metoprolol (MT) e do flurbiprofeno (FLU) em formulações farmacêuticas. A determinação quantitativa dos enantiômeros do atenolol e do metoprolol nos comprimidos foi realizada através de método cromatográfico validado. As condições analíticas foram padronizadas através do sistema de cromatografia líquida de alta eficiência, usando coluna do tipo carbamato de celulose tris-3,5-dimetilfenil, Chiralcel OD&reg;, (250x4.6 mm, 10&#181;m) como FEQ. As amostras foram cromatografadas à temperatura ambiente, com um volume de injeção de 20&#181; L. A detecção foi efetuada em 276 nm. Para o atenolol a fase móvel foi constituída de hexano:etanol:dietilamina:ácido acético (60:40:0,2:0,2 v/v/v/v), com vazão de 1,0 rnL/min. As curvas padrões do R-AT e do S-AT apresentaram boa linearidade entre 50,0-130,0&#181;g/rnL, com coeficiente de correlação de 0,9991 e 0,9980 respectivamente. As amostras comerciais A, B, C e D referentes a R-AT analisadas, apresentaram coeficiente de variação e percentual de recuperação de 1,15% e 101,06%; 0,74% e 99,25%; 1,05% e 102,57%; 0,84% e 101,57% respectivamente, já o coeficiente de variação e percentual de recuperação do S- AT nas amostras A, B, C e D foram 1,33% e 98,87%; 0,99% e 100,76%; 1,17% e 101,69%; 1,26% e 100,39%, respectivamente. Para o metoprolol a fase móvel foi constituída de hexano:etanol:dietilamina:ácido acético (40:60:0,2:0,2 v/v/v/v), com vazão de 0,8 rnL/min. As curvas padrões do R-MT e do S-MT apresentaram boa linearidade entre 30,0-110,0&#181;g/rnL, com coeficiente de correlação de 0,9988 e 0,9990 respectivamente. A amostra comercial analisada, apresentou coeficiente de variação e percentual de recuperação de 0,86% e 98,62% para R-MT e de 1,40% e 99,39% para S-MT. Um método cromatográfico foi desenvolvido e validado para separação e quantificação enantiomérica do FLU na forma farmacêutica. As condições analíticas foram padronizadas através do sistema de cromatografia líquida de alta eficiência, usando coluna do tipo Whelk-O 1&#174; (250x4,6 mm, 5,0 &#181;m) como FEQ. As amostras foram cromatografadas à temperatura ambiente, com um volume de injeção de 20&#181; L. A detecção foi efetuada em 246 nm. A fase móvel foi constituída de hexano:etanol:ácido acético (95:05:0,2 v/v/v), com vazão de 0,9 rnL/min. A curva padrão do S-FLU apresentou boa linearidade entre 2,0-18,0 &#181;g/mL, com coeficiente de correlação de 0,9993. A amostra comercial analisada apresentou coeficiente de variação e percentual de recuperação de 0,16% e 100,1% para R_FLU e 0,14% e 100,4% para S-FLU, respectivamente. Os métodos propostos permitam a separação quantitativa dos enantiômeros de AT, MT e FLU contidos nas formas farmacêuticas analisadas, com precisão e exatidão e que podem ser aplicados no controle de qualidade enantiomérico destes fármacos. / The majority of the therapeutic agents, frequently prescribed, are formulated and commercialized as racemic mixture, even so for some of them, it has been demonstrated that the pharmacological and/or toxic effect are confined only to one of the enantiomer. Besides, it is well known that the enantiomers can present different pharmacokinetic and pharmacodynamic profiles. In the present work we selected drugs belonging to two classes of clínical importance. These pharmaceuticals are widely prescribed in clinical practice such as, the beta-blockers (atenolol, metoprolol, pindoloI, betaxolol and nadolol) and the non-steroid anti-inflammatorydrugs (ibuprofen and flurbiprofen). Several references could be found in scientific literature that describes the use of high performance liquid chromatography with chiral stationary phase (HPLC-CSP) in pharmacological studies, seldom in the quantitative determination of enantiomers in pharmaceutical formulations. It is well known that the HPLC-CSP methods offer distinct advantages over classical techniques of isomeric separation and analysis, especially for the enantiomeric separation. The direct enantiomeric separation of atenolol metoprolol nadolol and betaxolol were obtained using CSP Chiralcel OD&#174;.The enantiomers of pindolol were separate utilizing CSP &#945;-Burke 2&#174; and those of ibuprofen and the flurbiprofen with CSP Whelk-O 1&#174;. In this work are presented efficient and sensitive methods for stereospecific determination of atenolol (AT), metoprolol (MT) and flurbiprofen (FLU) in pharmaceutical formulations. The stereoselective determination of atenolol and metoprolol in pharmaceuticals was performed through validated chromatographic method. The validation of liquid chromatographic methods was done utilizing a cellulose tris- 3,5-dimethylphenyl carbamate, Chiralcel OD&#174;, (250x4.6 mm, 10&#181;m)as CSP. The samples were analyzed at room temperature with injection volume of 20&#181;L and UV detection was made at 276nm. In case of atenolol, the mobile phase was constituted of hexane:ethanol:diethylamine:acetic acid (60:40:0.2:0.2 v/v), with a flow rate of 1.0 mL/min. Separate standard curve for R-AT and S-AT showed good linearity over a concentration range from 50-130 &#181;g/mL, with coefficient of correlation of 0.9991 and 0.998, respectively. The coefficient of variation and average recovery for R-AT in the samples A, B, C, and D were 1.15% and 101.06%; 0.74% and 99.25%; 1.05% and 102.57%; 0.84% and 101.57% respectively. The coefficient of variation and average recovery for S-AT in samples A, B, C and D were 1.33% and 98.87%; 0.99% and 100.76%; 1.17% and 101.69%; 1.26% and 100.39%, respectively. In case of metoprolol, the mobile phase was constituted of hexane:ethanol:diethylamine:acetic acid (40:60:0.2:0.2 v/v), with a flow rate of 0.8 m L/min. Separate standard curve for R-MT and S-MT showed good linearity over a concentration range fIom 30-110 &#181;g/mL, with coefficient of correlation of 0.9988 and 0.9990, respectively. The coefficient of variation and average recovery for R-MT in sample analyzed was 0.86% and 98.62% and for S-MT was 1.40% and 99.39%, respectively. A high performance liquid chromatographic method is developed and validated for enantiomeric separation and quantitative determination of FLU in pharmaceutical preparation. A WheIk-O 1&#174; column (250x4.6 mm, 5&#181;m)was used as chiral stationary phase (CSP). The mobile phase was constituted of hexane:ethanol:acetic acid (95:05:0.2 v/v/v), at a flow rate of 0.9 rnL/min and UV detection at 246nm. All experiments were done at ambient temperature. The S-FLU standard curve showed linearity over a concentration range from 2-18&#181;g/mL, (R2 = 0.9993). The coefficient of variation and average recovery of R-FLU were 0.16% and 100.13% and for S-FLU were 0.14% and 100.4%; respectively. The proposed methods permits quantitative separation of AT, MT and FLU enantiomers in pharmaceutical formulations studied with precision and accuracy. The proposed validated methods can be used in the enantiomeric quality controI of referred pharmaceutical drugs.