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1
Yilgor, Pinar. "Bioprocess Operation Parameters For Benzaldehyde Lyase Production." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605242/index.pdf.
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In this study, the effects of bioprocess operation parameters on benzaldehyde lyase production were systematically investigated. For this purpose, the research program was carried out in mainly four parts. In the first part of the study, Escherichia coli K12 (ATCC 10798), having the highest benzaldehyde lyase production capacity, was selected as the host microorganism. Next, using the selected microorganism, the production medium was designed in terms of its carbon and nitrogen sources. Among the investigated media, the highest cell concentration and benzaldehyde lyase activity were obtained as 1.8 kg m-3 and 745 U cm-3, respectively, in the medium containing 8.0 kg m-3 glucose, 5.0 kg m-3 (NH4)2HPO4 and the salt solution. Thereafter, by using the designed medium, the effects of bioreactor operation parameters, i.e., oxygen transfer and pH, were investigated in pilot scale bioreactor. Oxygen transfer effects on benzaldehyde lyase production were investigated at QO/VR=0.5 vvmN=250, 375, 500, 625, 750 min-1 and at QO/VR=0.7 vvm, N=750 min-1 conditions. The highest cell concentration and benzaldehyde lyase activity were obtained at 0.5 vvm, 500 min-1 condition as 2.3 kg m-3 and 860 U cm-3, respectively. Finally, the effect of pH was investigated for benzaldehyde lyase production process at Qo/VR=0.5 vvm, N=500 min-1 condition, at pHC=5.0, 6.4, 6.7, 7.0, 7.2 and 7.8 values. Among the investigated pH values, the highest cell concentration and enzyme activity were obtained at pHC=7.0 condition as 2.1 kg m-3
775 U cm-3. However, the values obtained at this condition, were lower than the values obtained at pHUC=7.2 uncontrolled pH operation. Hence, medium oxygen transfer condition and uncontrolled pH operation are found to be favorable for benzaldehyde lyase production.
2
Simsek, Ilke. "Benzaldehyde Lyase Catalyzed Synthesis Of Novel Acyloins." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610901/index.pdf.
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α
-Hydroxy phosphonates are versatile building blocks for the synthesis of many biologically active compounds that display antiviral, antibacterial, anticancer, pesticide activities beside their enzyme inhibitory activities such as they are the inhibitors of rennin or human immunodeficiency virus (HIV) protease and polymerase. Benzaldehyde lyase is able to catalyze not only C-C bond formation reactions but also C-C bond breaking reactions with high enantioselectivity that brings about the development of new synthetic methodologies for the synthesis of hydroxy ketones which are the key intermediates in the synthesis of many biologically active compounds due to the versatility of stereogenic center for developing structural diversity. There are several synthetic methodologies for the synthesis of hydroxy phoshonates however, in this work we have achieved the synthesis of hydroxy phoshonates through C-C bond forming reactions catalyzed by Benzaldehyde lyase that offers the use of green methodologies. Moreover, we have achieved the synthesis of hydroxy ketones which are versatile building blocks in the synthesis of many biologically active compounds via the immobilization of BAL enzyme on superparamagnetic solid support with high yield and high enantioselectivity.
3
Mackintosh, Robert William. "Benzyl alcohol dehydrogenase and benzaldehyde dehydrogenase of Acinetobacter calcoaceticus." Thesis, University of Glasgow, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281219.
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Simmonds, Julie. "Production of benzaldehyde by biotransformation using Pseudomonas putida ATCC 12633." Thesis, University of Kent, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244331.
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Boyle, Sarah Ann. "Oxidation of toluene." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387977.
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Smith, Derek John. "Femtosecond Laser Mass Spectrometry (FLMS)." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264149.
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7
Levent, Hande. "Feeding Strategy Development For Benzaldehyde Lyase Production By Recombinant Escherichia Coli Bl21." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609596/index.pdf.
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This study focuses on the molasses based complex medium design for benzaldehyde lyase production by recombinant E. coli BL21 and development of a feeding strategy based on the designed complex medium. For this purpose, firstly, the effects of molasses were investigated in laboratory scale bioreactors. As E. coli BL21 was not able to utilize sucrose, molasses was pretreated and hydrolyzed to fructose and glucose. Thereafter, effect of pretreated molasses concentration was investigated in the range of 16 to 56 kg m-3 by batch-bioreactor experimentsand the highest cell concentration and benzaldehyde lyase activity were obtained as CX=5.3 kg m-3 and A=1617 U cm-3, respectively, in the medium containing 7.5 kg m-3 glucose and 7.5 kg m-3 fructose. Then, different feeding strategies were developed to produce efficient cells with high concentration and BAL activity. In the first strategy, after 10 hours of batch-cultivation with molasses based medium having 7.5 kg m-3 glucose and 7.5 kg m-3 fructose concentration, based on the airflow rate, pretreated molasses was fed to the system. When air flow rate decreased considerably, fed was given to the system that results in increase in glucose and fructose concentration in the medium to 2.5 kg m-3. At the end of the process, the highest cell concentration obtained was CX=7.4 kg m-3. The maximum activity was reached at 20th hour as A=2360 U cm-3. On the other hand, as air flow variation only demonstrated the absence of glucose not fructose, a second strategy, based on the detection of the fructose and glucose concentrations during the process, was applied. In this strategy when glucose and fructose were depleted, fed was given to the system that results in increase in glucose and fructose concentration in the medium to 2.5 kg m-3
and the highest BAL activity was obtained as 2370 U cm-3 at t= 26 h where the cell concentration was 7.5 kg m-3. At the last strategy, when glucose and fructose were depleted, fed was given to the system that results in increase in CGlucose=1.5 kg m-3 and CFructose=1.5 kg m-3 in the production medium to decrease the accumulation of acetic acid. By this strategy highest cell concentration was obtained as 8.04 kg m-3 at t=24 h and the highest BAL activity was 2315 U cm-3. These strategies could be accepted having the same BAL activity with little distinctions. However, cell concentration of the last one was higher than others and also the lowest amount of carbon source was used. Thus, last one could be chosen as the most favorable strategy.
8
Taspinar, Hatice. "Exponential Feeding Strategy Development For Benzaldehyde Lyase Production By Recombinant Escherichia Coli." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612311/index.pdf.
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In this study, the aim was to investigate the effects of exponential feeding strategy on benzaldehyde lyase (BAL) production by recombinant Escherichia coli BL21. For this purpose, the effects of medium components were investigated to optimize the initial medium composition of the fed-batch fermentations. For the batch bioreactor operations, the highest cell concentration and BAL activity were achieved in a media containing 30 g L-1 pretreated molasses, and 5 g L-1 (NH4)2HPO4 as 5.07 g L-1, and 1611 U ml-1 at t=8 h, respectively. Thereafter, in order to increase the cell growth and BAL production while avoiding acetate accumulation, fed-batch bioreactor operations were conducted with exponential feeding at different specific growth rates namely, 0.1 h-1 (mu-0.1), 0.15 h-1 (mu-0.15), and 0.2 h-1 (mu-0.2), and a combined exponential and constant feeding (mu-0.2+) strategy. In the experiments, 9 hours of batch-wise operation with the optimized production medium was followed by a fed-batch operation phase using the pre-determined exponential feeding profiles and for mu-0.2+ operation after 10 hours of exponential feeding as mu-0.2, where the feed rate was kept constant at 21.6 g h-1. Additionally, the plasmid stability was investigated using the feeding method of mu-0.2+ operation with antibiotics in the feed solution, and it was observed that the plasmid was stable. Among the three exponential feeding conditions, the highest cell concentration and BAL activity were determined in
9
Jones, Rheinallt M. "The catabolism of aromatic esters by Acinetobacter sp. ADP1." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322563.
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Guena, Thierry. "Electrochemistry of aryl carbonyl compounds in flow cells." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243180.
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Azzolina, Jury Federico. "Préparation et caractérisation de zéolithes dopées par des métaux de transition : Mesure de propriétés diélectriques et magnétiques et leur application à la synthèse de composés chimiques sous irradiation microondes." Thesis, Rouen, INSA, 2013. http://www.theses.fr/2013ISAM0025.
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Cette étude est centrée sur la synthèse et la préparation de zéolithes modifiées par des métaux de transition avec leurs applications en catalyse sous irradiation microondes. Des travaux précédents ont montré l’intérêt de modifier des zéolithes avec des métaux de transition pour leur application sur des réactions d’oxydation et d’utiliser les microondes afin d’augmenter les vitesses de réaction. Dans cette thèse, nous avons étudié deux types de structure zéolithique (MEL et FAU) dopés par des métaux de transition (Co, Mn, Fe, Zn, Ni, Cr) à différentes concentrations. Une étude classique de caractérisation a permis d’augmenter la connaissance sur la préparation de zéolithes modifiées et de comprendre leur influence sur l’activité catalytique. La réaction d’oxydation partielle du styrène pour la production du benzaldéhyde a été choisie comme réaction modèle. La zéolithe Co-ZSM-11 a présenté la meilleure activité catalytique dans cette étude ainsi que par rapport à d’autres catalyseurs présentés dans la littérature.Les réactions d’oxydation du styrène ont été étudiées sous irradiation microondes et sous chauffage conventionnel. Aucune différence sur l’activité des zéolithes dopées n’a été observée pour les deux types de chauffage. Les faibles valeurs de permittivités et perméabilités des zéolithes dopées par des métaux de transition rendent difficile l’intensification du procédé d’obtention de benzaldéhyde à partir de l’oxydation du styrène sous microondes. Les paramètres de la réaction modèle ont été optimisés et une étude cinétique a été menée avec la zéolithe Co-ZSM-11. Enfin, le chauffage par hystérésis diélectrique a été utilisé dans la synthèse de zéolithes ZSM-11. Le temps de synthèse a été considérablement réduit (80%) par rapport au temps nécessaire sous chauffage conventionnelThis study focuses on the synthesis and preparation of modified zeolites with transition metals and theirs applications in catalysis under microwave irradiation. Previous works have shown interest in modifying zeolites with transition metals for their application to oxidation reactions and in using microwave irradiation in order to increase the reaction rates. In this thesis, we studied two types of zeolite structure (MEL and FAU) doped with transitionmetals (Co, Mn, Fe, Zn, Ni, Cr) at different concentrations. A classic characterization study has increased the knowledge on the preparation of modified zeolites and the understanding of their influence on thecatalytic activity. The styrene partial oxidation reaction for benzaldehyde production was chosen as amodel reaction. Co-ZSM-11 zeolite presented the best catalytic activity in this study and also compared to other catalysts found in the literature. The styrene oxidation reactions were studied under microwave irradiation and under conventional heating. No difference in the activity of doped zeolites was observed for both types of heating. The low values of permittivity and permeability of zeolites doped with transition metals make difficult the intensification of the benzaldehyde production process from styrene oxidation under microwave. The parameters of the model reaction have been optimized and a reaction kinetic study was carried out by using the Co-ZSM-11 zeolite. Finally, the hysteresis dielectric heating was used in the synthesis of ZSM-11. The synthesis time was significantly reduced (80%) under microwave irradiation compared to conventional heating
12
Grosjean, Christophe. "The Strecker reaction of benzaldehyde, amines and cyanide : some mechanistic and synthetic studies." Thesis, Durham University, 2004. http://etheses.dur.ac.uk/3043/.
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The Strecker reaction involves the formation of aminonitriles by the reaction of an aldehyde with an amine in the presence of cyanide ions. In this work kinetic, equilibrium and synthetic measurements have been made using benzaldehyde, or 4-nitrobenzaldehyde, as the aldehyde and benzylamine or allylamine as the amine. A side reaction involves the formation of a cyanohydrin from benzaldehyde and cyanide ion. The equilibria involved m the reaction and their pH dependence have been examined. For comparison values for the equilibrium constants for the reaction of benzaldehyde with sulfite are also reported. The syntheses and structural characterisations of N-benzylidene benzylamine, N-benzylidene allylamine and N-(4-nitro)-benzylidene benzylamine are reported. A major part of the thesis is concerned with the kinetics and equilibria involved in the reaction of N-benzylidene benzylamine and N-benzylidene allylamine with cyanide in aqueous solutions. The results are compatible with the rate-determining step involving reaction of the corresponding iminium ions with cyanide ions. The pH profile is bell-shaped with a plateau between pH = 6.5 and 8.5 defined by the pK(_a) values of the iminium ions and hydrogen cyanide. pK(_a) values of 6.14 ± 0.1 and 6.05 ± 0.1 have been calculated for N- benzylidene benzyliminium and N-benzylidene allyliminium ions respectively. Rate constants for reaction of cyanide ion with these cations are 6.70x10(^3) and 1.03x10(^4) dm(^3)mol(^-1)s(^-1) respectively. The hydrolysis reactions of imines to yield benzaldehyde have also been quantitatively investigated. The relatively low reactivity found for those iminium ions may be attributed to charge delocalisation in the aromatic ring. An important aspect of the Strecker reaction is the possibility of forming enantiomerically pure products. The asymmetric catalysis by Salen metal complexes of the reaction of the imines with trimethylsilyl cyanide in organic solvents has been investigated. Various methods for the determination of the enantiomeric excess were tested and the most reliable was found to be use of camphorsulfonic acid. The reaction carried out in the presence of a Salen V(V) complex was optimised to yield aminonitriles in a 80% e.e. at -30 C and 69% e.e. at room temperature. Trifluoroacetic anhydride (TFFA) has been reported in the literature as a reagent for reaction with aminonitriles to allow the separation of enantiomers. Here the reaction of imines with TFAA in acetonitrile and in benzene has been investigated In each solvent there are strong reactions yielding hifluoroacetylated derivatives which are thought to exist in both ionic and covalentiy-bound forms.
13
Kaya, Hande. "Comparison Of Benzaldehyde Lyase Production Capacity In Recombinant Escherichia Coli And Recombinant Bacillus Species." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607272/index.pdf.
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In this study, the benzaldehyde lyase (BAL, EC 4.1.2.38) production in E. coli
BL21 (DE3) pLySs as intracellular and in Bacillus species as extracellular were
investigated, and comparison of the production capacity of the enzyme in the
developed recombinant microorganisms were compared. For this purpose, firstly,
PCR amplified bal gene was cloned into pRSETA vector which is under the control
of strong T7 promoter and expressed in E. coli BL21 (DE3) pLysS strain. With
developed recombinant E. coli BL21 (DE3) pLySs cells, the effect of bioprocess
parameters was systematically investigated. Among the investigated media, the
highest cell concentration and benzaldehyde lyase activity were obtained as 2.0
kg m-3 and 1060 U cm-3, respectively, in the medium containing 20.0 kg m-3
glucose, 11.8 kg m-3 (NH4)2HPO4 and the salt solution. Thereafter, oxygen
transfer effects on benzaldehyde lyase production were investigated at air inlet
v
rate of QO/VR = 0.5 vvm, and agitation rates of N=500 and 750 min-1 and at
QO/VR = 0.7 vvm, N=750 min-1 in pilot scale bioreactor and the highest cell
concentration and volumetric BAL activity were found as 1.7 kg m-3 and 990 U
cm-3, respectively, at 0.5 vvm, 750 min-1 condition. Next, the signal DNA
sequence of serine alkaline protease (SAP) from B. licheniformis DSM 1969
chromosomal DNA (pre-subC) was fused in front of the bal by using PCR-based
gene splicing by overlap extension (SOE) method. The fusion product of hybrid
gene first cloned into pUC19 plasmid, thereafter sub-cloned into pBR374 shuttle
vector and recombinant plasmid was transferred into various Bacillus species.
However, no extracellular production of benzaldehyde lyase was observed in
none of the developed recombinant Bacillus species, probably because of
ineffective secretion system, inefficient folding of heterologous protein,
degradation of enzyme due to proteolytic activity or high inactivation rate of the
enzyme.
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Nyoni, Dubekile. "Mechanistic studies of unusual Miruta-Baylis-Hillman reactions." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1006692.
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This study has focussed on the application of synthetic, kinetic and exploratory theoretical methods in elucidating the reaction mechanisms of four Morita-Baylis-Hillman (MBH) type reactions, viz, i) the reactions of the disulfide 2,2'-dithiodibenzaldehyde with various activated alkenes in the presence of DBU and Ph₃P, ii) the reactions of chromone-3-carbaldehydes with MVK, iii) the reactions of chromone-2-carbaldehydes with acrylonitrile and iv) with methyl acrylate. Attention has also been given to the origin of the observed regioselectivity in Michaelis-Arbuzov reactions of 3-(halomethyl)coumarins. Cleavage of the sulfur-sulfur bond of aryl and heteroaryl disulfides by the nitrogen nucleophile DBU has been demonstrated, and a dramatic increase in the rate of tandem MBH and disulfide cleavage reactions of 2,2'-dithiodibenzaldehyde with the activated alkenes, MVK, EVK, acrylonitrile, methyl acrylate and tert-butyl acrylate has been achieved through the use of the dual organo-catalyst system, DBU-Ph₃P – an improvement accompanied by an increase in the yields of the isolated products. Detailed NMR-based kinetic studies have been conducted on the DBU-catalysed reactions of 2,2'-dithiodibenzaldehyde with MVK and methyl acrylate, and a theoretical kinetic model has been developed and complementary computational studies using Gaussian 03, at the DFT-B3LYP/6-31G(d) level of theory have provided valuable insights into the mechanism of these complex transformations. Reactions of chromone-3-carbaldehydes with MVK to afford chromone dimers and tricyclic products have been repeated, and a novel, intermediate MBH adduct has been isolated. The mechanisms of the competing pathways have been elucidated by DFT calculations and the development of a detailed theoretical kinetic model has ensued. Unusual transformations in MBH-type reactions of chromone-2-carbaldehydes with acrylonitrile and methyl acrylate have been explored and the structures of the unexpected products have been established using 1- and 2-D NMR, HRMS and X-ray crystallographic techniques. Attention has also been given to the synthesis of 3-(halomethyl)coumarins via the MBH reaction, and their subsequent Michaelis-Arbuzov reactions with triethyl phosphite. An exploratory study of the kinetics of the phosphonation reaction has been undertaken and the regio-selectivity of nucleophilic attack at the 4- and 1'-positions in the 3-chloro- and 3-(iodomethyl)coumarins has been investigated by calculating Mulliken charges, LUMO surfaces and Fukui condensed local softness functions.
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Okrasa, Krzysztof. "Utilisation de l'oxydation enzymatique en synthèse organique." Paris 11, 2004. http://www.theses.fr/2004PA112001.
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Nous avons étudié le potentiel en synthèse organique de la peroxydase de Coprinus cinereus (Cip). La peroxydase catalyse l'oxydation par l'air des thiols en disulfures, en milieu aqueux ou sur support minéral en absence de solvant. Cette réaction s'est révélée cependant non-énantiosélective. Nous avons étudié la possibilité de produire in situ de façon contrôlée le peroxyde d'hydrogène, substrat de la Cip, pour empêcher sa désactivation et pour que les réactions catalysées soient énantiosélectives. Divers systèmes photochimiques et chimiques ont été testés, certains avec un résultat modeste. Nous avons mis au point deux systèmes bienzymatiques : D-glucose oxydase /Cip et D-aminoacide oxydase/Cip, où le peroxyde d'hydrogène est produit progressivement par l'oxydase et utilisé par la Cip. Dans le système utilisant la D-aminoacide oxydase, le flux de peroxyde d'hydrogène dépend de son utilisation par la peroxydase. Nous avons réalisé l'oxydation de divers aryl-méthyl sulfures par ces systèmes. Les sulfoxydes de configuration absolue S ont été obtenus avec de bons rendements et un haut excès énantiomérique (jusqu'à 97 % ee). Ces systèmes bienzymatiques ont également permis l'epoxydation modérément énantiosélective du para-chlorostyrène (ee=45%). L'oxydation des autres oléfines testées a donné cependant des produits racémiques avec des rendements médiocres. Nous avons utilisé le système glucose oxydase/Cip dans les sels liquides comme milieu réactionnel. L'oxydation des sulfures y a été moins rapide que dans l'eau mais les sulfoxydes ont été obtenus avec un haut excès énantiomérique et la configuration S (comme dans l'eau). Les enzymes sont stables dans ce milieu, peuvent être récupérées, recyclées et réutilisées plusieurs fois. Le système D-aminoacide oxidase/Cip a été appliqué à la production in vitro de benzaldéhyde à partir de phénylalanine dans des conditions strictement définies. Nous proposons un mécanisme probable pour cette biotransformationThe potential usefulness of Coprinus cinereus peroxidase (Cip) in organic synthesis has been studied. This peroxidase cans catalyse the oxidation of thiols into disulfides, either in aqueous medium or on a mineral support without solvent. This reaction however was found to be non-enantioselective. We have investigated the possibility to produce in situ hydrogen peroxide, the normal substrate of peroxidase, in order to avoid its de activation and to promote enantioselective oxidation. Various chemical and photochemical systems were tested, some of them with a relative success. Two bienzymatic systems were elaborated : D-glucose oxidase /Cip and D-aminoacid oxidase/Cip, in which hydrogen peroxide continuously produced by the oxidase is immediately used by the peroxidase. With D-amino acid oxidase, the flux of hydrogen peroxide is further submitted to its utilisation by Cip. Various aryl-methyl sulfides have been oxidised by these systems. Chiral sulfoxides, having an S absolute configuration, were obtained with good yields and high enantiomeric excess (up to 97%). These bienzymatic systems could also oxidise p-chlorostyrene into the corresponding epoxide with a moderate ee (45%). Other alkenes led to racemic epoxides with a low yield. The glucose oxidase/Cip system was shown to be active in ionic liquids as a reaction medium. The oxidation was slower than in water but sulfoxides were obtained with the same enantiomeric excess and the same S configuration as in water. The enzymes were stable in this medium, and could be recycled and reused several times. The D-aminoacid oxidase/Cip system was used for an in vitro production of benzaldehyde from phenylalanine in fully controlled conditions. We propose a likely mechanism for this transformation
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Buyuksungur, Arda. "Cloning And Expression Of Benzaldehyde Lyase Gene From Pseudomonas Fluorescens Biovar I In Pichia Pastoris." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607532/index.pdf.
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Benzaldehyde lyase (BAL, EC 4.1.2.38) from Pseudomonas fluorescens Biovar I, a thiamine pyrophosphate (ThDP) dependent enzyme, catalyzes the enzymatic kinetic resolution of racemates by C-C bond cleavage and concomitant C-C bond formation. In this study, benzaldehyde lyase gene from Pseudomonas fluorescens Biovar I was cloned into Pichia pastoris, with the aim of the extracellular production of the enzyme. For this purpose, firstly, PCR amplified bal gene was cloned into an integration vector pPICZalphaA. Thereafter the recombinant plasmid pPICZalphaA::bal was transformed into P.pastoris. Extracellular benzaldehyde lyase enzyme was expressed under the control of the strong AOX promoter and the secretion of the enzyme in the fermentation medium was achieved by means of S. cerevisiae alpha factor signal sequence. The recombinant cells were grown for 48-72 hours in solid medium then the cells inoculated in glycerol containing medium. After being separated by centrifugation cells were transferred into methanol containing production medium. In methanol containing medium cells were grown for 72 h. Starting from t=24 h methanol was added to medium as an inducer of AOX promoter and the carbon source in order to produce BAL in every 24 hour. SDS-PAGE analyses illustrated that extracellular benzaldehyde lyase enzyme produced by the recombinant P.pastoris strain had the size of 59 kDa, which is the size of benzaldehyde lyase monomer. FPLC analysis showed that concentration of the tetrameric form of benzaldehyde lyase enzyme, active form, was much less than the monomeric form of the enzyme indicating that the enzyme produced by recombinant P.pastoris mostly could not fold into multimeric form in the fermentation medium.
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Angardi, Vahideh. "Influence Of Oxygen Transfer On Benzaldehyde Lyase Production By Recombinant Escherichia Coli Bl21(de3) Plyss." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608779/index.pdf.
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In this study, the effects of oxygen transfer conditions on the synthesis of the enzyme benzaldehyde lyase as intracellular in recombinant E. coli BL21 (DE3) pLysS was investigated sistematically and a comprehensive model was developed to determine benzaldehyde lyase activity. For this purpose, the research program was carried out in mainly two parts. In the first part of study, the effects of oxygen transfer together with the mass transfer coefficient (KLa), enhancement factor E (=KLa/KLao), volumetric oxygen transfer rate, volumetric and specific oxygen uptake rates, mass transfer and biochemical reaction resistancesmoreover, the variation in product and by-product distribution, specific substrate uptake rates, yield and maintenance coefficient were investigated in the pilot scale batch bioreactor at QO/VR = 0.5 vvm and agitation rates of N= 250, 500, 625, and 750 min-1, and dissolved oxygen levels DO= 20%, 40% conditions, while medium components were CGlucose= 8.0 kg m-3, C(NH4)2HPO4= 5.0 kg m-3 and salt solution at controlled pHc=7.2. The highest cell concentration and benzaldehyde lyase activity were obtained at DO=40% condition as 3.0 kg m-3 and A=1095 Ucm-3, respectively. v Then a mathematical model was proposed to estimate benzaldehyde lyase activity as function of time, agitation rate, cell concentration, dissolved oxygen concentration, and by-product concentration with reasonable accuracy.
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Hosrik, Birsu Semra. "Benzaldehyde Lyase From Pseudomonas Fluorescens Biovar I Mediated Biotransformation For The Synthesis Of Chiral Alpha Hydroxy Ketones." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611456/index.pdf.
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Optically active α
-hydroxy ketones are important subunits of many biologically active compounds and indispensable synthons for asymmetric synthesis. Benzaldehyde Lyase from Pseudomonas fluorescens Biovar I is a novel ThDP-dependent enzyme that catalyzes the synthesis of benzoin type chiral &
#945
-hydroxy ketones starting from both benzaldehyde and racemic benzoin derivatives. Benzaldehyde Lyase is the first example of enzymes in the literature which leads to a chemical resolution of enantiomers of benzoin derivatives through a C-C bond cleavage reaction. Chiral 2-hydroxypropiophenone derivatives are formed by benzaldehyde lyase (BAL), catalyzing C-C bond formation after a selective C-C bond cleavage of a benzoin derivative accepted as a substrate. The enzyme uses only the (R)-benzoin derivatives as substrate for the formation of (R)-HPP derivatives and it is highly stereoselective. Thus, in the presence of the acetaldehyde as the acceptor aldehyde, the C-C bond cleavage of the benzoin molecule followed by the carboligation of the acetaldehyde to yield chiral 2-hydroxy propiophenone derivatives. Given the racemic benzoin to the enzyme as the substrate in the presence of acetaldehyde, both the racemic resolution of the substrate, revealing the unreacted (S)-Benzoin and the formation of the corresponding R-HPP occur.
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Natalia, Dessy [Verfasser]. "Benzaldehyde lyase catalysed carboligation of 2-furaldehyde into (R)-2,2’-furoin in non-conventional media / Dessy Natalia." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2012. http://d-nb.info/1026080231/34.
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Bouya, Houceine. "Dégradation par voie électrochimique de nitro-benzaldehyde et cyperméthrine et étude cinétique d’oxydation atmosphérique du bupirimate et nitrobenzaldehyde." Thesis, Reims, 2015. http://www.theses.fr/2015REIMS018/document.
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Cette thèse porte sur l’étude des composés organiques semi-volatils, notamment les pesticides et les composés nitro-aromatiques dans les deux compartiments l’eau et l’atmosphère. La première partie de ce travail concerne l'optimisation des différents paramètres expérimentaux (concentration initiale des composés, concentration de l’électrolyte support, température et la densité de courant imposé) de la dégradation de la cypermethrine et du 2-Nitrobenzaldehyde (2-NBA) par oxydation direct moyennant les électrodes de l'oxyde d'étain (SnO2) et le diamant dopé au bore (DDB). Cette dégradation a été suivie par les analyses de la demande chimique en oxygène (DCO) et la chromatographie en phase gazeuse. Les résultats obtenus montrent que le taux de minéralisation dépasse 80 % pour le cypermethrine en utilisant le DDB. La deuxième partie est consacrée à l'étude de la réactivité du bupirimate vis-à-vis de l’ozone et les radicaux OH• en phase hétérogène. Les résultats obtenus montrent que les valeurs de la constante cinétique pour la réaction du bupirimate avec les radicaux OH• et l’ozone sont respectivement de l’ordre de 1,06 x 10-12 et 5,4 x 10-20 (cm3 molecule-1 s-1). La durée de vie du bupirimate est de plusieurs mois par rapport à l'ozone et de quelques jours par rapport aux radicaux OH•. Les spectres UV et la réactivité homogène vis-à-vis des radicaux OH• du 2-Nitrobenzaldehyde (2-NBA) a été déterminé en phase gazeuse. Les études cinétiques ont été réalisées dans une chambre atmosphérique couplée à un spectromètre IR. Les résultats obtenus montrent que le 2-NBA est sensibles à la photolyse dans l’atmosphère et que sa réactivité vis-à-vis des radicaux OH• est non négligeable. En effet, la durée de vie atmosphérique de ce composé est relativement courte. Elle varie de quelques minutes à quelques heures. Le 2-NBA est donc non persistant dans l’atmosphèreThis thesis focused on the study of semi-volatile organic compounds (SVOC), including pesticides and nitro-aromatics compounds in the two compartments, water and atmosphere. The first part of this work concerns the optimization of the different experimental parameters in order to mineralize two compounds (cypermethrin and of 2-Nitrobenzaldehyd), those parameters are initial concentration of compounds, concentration of the electrolyte support, temperature and the density of the current imposed. This mineralization has been done by a direct oxidation through the electrodes of the tin oxide (SnO2) and Boron Doped Diamond (BDD). The degradation process has been followed by the DCO analyzes and the gas chromatography. It has been shown that the rate of mineralization exceeds 80 % for the cypermethrine compound using BDD electrode. The second part is devoted to study the reactivity of bupirimate in heterogeneous phase using ozone and OH radicals as oxidant. The obtained results show that the rate constant values of the analyte are (1,06 ± 0,87) x 10-12 and (5,4 ± 0,3) x 10-20 (cm3 molecule-1 s-1) relative to heterogeneous OH-oxidation and O3, respectively. Such values implicate tropospheric life-times that vary from a few days to several months, meaning that these compounds are relatively persistent and may be transported to regions far from their point of application. The UV-absorption spectra and homogeneous OH-reactivity of 2-Nitrobenzaldehyde compound in the gas phase are investigated. The kinetic studies have been carried out in an atmospheric chamber coupled to an IR spectrometer. The results obtained indicate that the compound studied is susceptible to photolysis in the atmosphere and he exhibit strong reactivity towards OH-radicals. Generally speaking, the atmospheric life-time of this compound is relatively short, in the order of a few minutes to hours and he is non-persistent. Rate constants present a slight variation with the temperature
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Gambe, Jess. "Non-hydrolytic synthesis and structure of ZrO2 nanoparticles." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0011/document.
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Ce travail traite de la synthèse et de la caractérisation structurale de nanoparticules d'oxyde de zirconium (ZrO2) ainsi que de leurs relations taille/structure. Nous avons élaboré des nanoparticules de taille inférieure à 5 nm avec une distribution de taille étroite en utilisant une voie sol-gel non hydrolytique solvothermale. La diffraction des rayons X classique a été utilisée pour évaluer la taille des cristallites via des affinements de Rietveld et la diffusion totale des rayons X pour extraire les fonctions de distribution des paires (PDF) des échantillons et effectuer leur analyse structurale.Nous avons réussi à synthétiser des nanoparticules cristallines de ZrO2 d'une taille d'environ 3 nm et quasi mono-disperses. Nous avons montré qu'une addition d'hydroxyde de sodium dans le mélange réactionnel était pertinente pour obtenir des nanoparticules bien cristallisées et monophasées présentant une structure moyenne soit monoclinique soit tétragonale en fonction du solvant utilisé, respectivement dans le benzaldéhyde ou dans l'alcool benzylique. Enfin, la dilution de l'alcool benzylique par l'anisole, un solvant inerte, conduit au contrôle fin de la taille moyenne des nanoparticules de 3,2 nm à 2 nm selon l'étude MET.Ces trois échantillons principaux préparés dans le benzaldéhyde alcalinisé, l'alcool benzylique ou l'anisole ont été soumis à une analyse structurale complète. Selon leur analyse PDF, ces trois échantillons offrent un aperçu de la compréhension des propriétés structurales de ces petites particules.La PDF expérimental de l'échantillon préparé avec du benzaldéhyde coïncide avec la PDF affinée d'un modèle structural monoclinique. Cependant, la PDF expérimentale de l'échantillon préparé avec de l'alcool benzylique n'est conforme à aucun des polymorphes connus de ZrO2 ayant une structure dérivée de la fluorine, mais présente plutôt une structure tétragonale moyenne avec des distorsions monocliniques à l'ordre local. Enfin, la PDF expérimentale de l'échantillon préparé avec de l'anisole présente de fortes distorsions structurales dans le domaine de l'ordre à moyenne distance, mais aussi une structure de type monoclinique à l'ordre local.Ensuite, l'échantillon préparé avec l'anisole a été soumis à un vieillissement assisté thermiquement (3 à 24 jours) et on a ajouté des quantités variables d'eau ex-situ (teneur en volume de 0,3 à 5%). Nous avons observé que les nanoparticules évoluaient d'une phase contenant un désordre élevé (3 jours) à une structure mieux cristallisée (24 jours) correspondant à une structure tétragonale moyenne tout en maintenant une distorsion monoclinique à l'ordre local. De manière similaire, l'addition d'eau ex-situ sur le mélange réactionnel favorise une cristallisation plus rapide et favorise l'apparition de pics typiques de la structure monoclinique. Cependant, la formation de phase monoclinique a été inhibée par la présence d'hydroxyde de sodium, mais limitée à environ 2% en volume d'eau, et une valeur plus élevée que cette quantité conduit à la formation de grandes particules de structure monocliniqueThis work deals with the synthesis and the structural characterization of zirconium oxide nanoparticles (ZrO2) as well as their size/structure relationships. We elaborated nanoparticles with a size inferior to 5 nm and a narrow size distribution using a non-hydrolytic solvothermal sol-gel route. Classical X-ray diffraction was used to evaluate the crystallite size via Rietveld refinement and X-ray total scattering to extract the pair distribution functions (PDF) of the samples for structural analysis.We succeeded in synthesizing crystalline nanoparticles of ZrO2 with a size of about 3 nm and quasi mono-dispersed. We showed that an adjusted addition of sodium hydroxide into the reaction mixture was pertinent to obtain a well crystallized and single-phase nanoparticles exhibiting an average monoclinic or tetragonal structure in benzaldehyde or in benzyl alcohol, respectively. Finally, the dilution of benzyl alcohol by anisole, an inert solvent, lead to the fine tuning of average crystallite size of the nanoparticles from 3.2 nm to 2 nm according to the TEM investigation.Those three major samples prepared in alkalinized benzaldehyde, benzyl alcohol, or anisole were subjected to complete structural analysis. According to their PDF analysis, these three samples offer an insight to the understanding of structural properties of such small particles.The experimental PDF of the benzaldehyde-prepared sample coincide with the refined PDF of a monoclinic structural model. However, the experimental PDF of the benzyl alcohol-prepared sample does not conform to any of the known polymorphs of ZrO2 having a fluorite-derived structure but rather it has an average tetragonal structure and a monoclinic distortion at the short-range order. Lastly, the experimental PDF of the anisole-prepared sample has large structural distortion at the medium-range order but has monoclinic structural features at the short-range order. We then subjected the anisole-prepared sample by thermally assisted ageing (3 to 24 days) and addition of varied amounts ex-situ water (0.3 to 5% volume content). We observed that the nanoparticles evolve from a phase containing high disorder (3 days) to a state of higher structural order (24 days) that fits with the average tetragonal structure while maintaining a monoclinic distortion at the short-range order. Similarly, the addition of ex-situ water onto the reaction mixture promoted a faster crystallization and promotes the onset of peaks that aligns with the monoclinic structure. However, the formation of monoclinic phases was inhibited by the presence of sodium hydroxide but limited to about 2% volume water content and higher than this amount lead to the formation of large particles with monoclinic structure
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Ayhan, Peruze. "Novel Bioconversion Reactions For The Syntheses Of A-hydroxy Ketones." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12610354/index.pdf.
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The objective of the study presented here was to develop either enzymatic or whole cell mediated green procedures for the syntheses of a-hydroxy ketones.
Production of optically active synthons is crucial for the preparation of fine chemicals. Enzymes and whole-cell biocatalysts have proven to be excellent vehicles with their chiral nature for the biotransformations. Under the light of
this discussion, firstly benzaldehyde lyase [BAL, (EC 4.1.2.38)] was used in novel C-C bond formation reactions to obtain interesting and biologically important precursors2-Hydroxy-1-arylethan-1-ones and functionalized aliphatic acyloin derivatives. All the compounds were obtained with high yields and in the case of aliphatic acyloin derivatives with high enantiomeric excesses (ee&rsquo
s). Another strategy was to use whole cell biocatalysis. A.flavus 200120 was found to be a promising biocatalyst with the ability to catalyze a broad range of reactions
reduction, hydrolysis and deracemization, while another fungus
A. oryzae 5048 was utilized in bioreduction reactions of benzil and its derivatives. Each reaction was investigated, optimized and thus enhanced via medium design. Products were obtained with high yields and ee&rsquo
s. To sum up, in this study novel efficient green procedures were developed to synthesize various ahydroxy ketones with high yield and stereoselectivity. These newly established methods present promising alternatives to classical chemical methodologies.
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Kaiser, Moacir. "Avaliação pré-clínica em roedores do perfil farmacocinético do benzaldeído semicarbazona livre e complexado em ß-ciclodextrina." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/16458.
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Objetivos: Avaliar a farmacocinética e a distribuição tecidual do benzaldeído semicarbazona livre (BS) e incluso em ß-Ciclodextrinas (BS/ß-CD) após administração de diversas doses por diferentes vias de administração. Metodologia: As concentrações plasmáticas de BS foram quantificadas através de método analítico por CLAE-UV desenvolvido e validado, após administração das doses de 10 mg/kg i.v. bolus e 50 e 100 mg/kg p.o. da droga livre e 10 mg/kg i.v. bolus e 50 mg/kg p.o. da droga complexada a ratos Wistar (n = 8 animais/grupo). Os perfis plasmáticos foram avaliados individualmente pelas abordagens não-compartimental e compartimental para determinação dos parâmetros farmacocinéticos. A avaliação compartimental foi realizada utilizando software Scientist 2.0.1 (Micromath®). A ligação do BS a proteínas plasmáticas foi determinada por ultrafiltração na faixa de 1,0 a 60,0 µg/mL. O perfil de penetração tecidual da droga livre e complexada foi investigado em diferentes órgãos utilizando o método de homogeneizado de tecido até 5 h após administração de dose 10 mg/kg i.v. A penetração cerebral também foi avaliada para a droga livre e inclusa em ß-CD após a dose de 50 mg/kg até 4 h após administração (n = 3 animais/tempo coleta). Resultados e Discussão: A fração livre do BS em plasma de ratos foi de 34 ± 5%. O modelo de um compartimento descreveu adequadamente todos os perfis plasmáticos estudados. Após doses intravenosa (10 mg/kg) e oral (50 mg/kg), parâmetros farmacocinéticos como Vd (1,6 ± 0,5 e 2,2 ± 0,8 L/kg, respectivamente) e Cltot (1,4 ± 0,5 and 1,8 ± 0,5 L/h×kg, respectivamente) foram maiores para o BS complexado em relação à droga livre, embora os t1/2 (0,8 ± 0,1 h-1) mantiveram-se similares (p < 0,05). A biodisponibilidade oral do BS/ß-CD (~37%) foi aproximadamente o dobro daquela observada para a droga livre (~20%). O fator de penetração cerebral após doses intravenosa (2,8) e oral (2,5), assim como tempo de residência médio, foram maiores para a droga complexada, independente da via de administração avaliada. Conclusões: A farmacocinética do BS livre e complexado mostra uma rápida distribuição tecidual e uma rápida eliminação. A maior penetração cerebral do complexo em relação à droga livre mostra que a ß-CD é uma estrutura capaz de vetorizar, reter e modificar a liberação do BS nesse órgão, explicando os achados farmacodinâmicos prévios.Purpose: This study aimed to investigate the pharmacokinetics and tissue distribution of benzaldehyde semicarbazone (BS) free and complexed with ß- cyclodextrin (BS/ß-CD) after administration to rodents at different doses by diverse routes. Methodology: BS plasma concentrations were determinated in Wistar rats after administration of 10 mg/kg i.v bolus and 50 and 100 mg/kg p.o. for the free drug and 10 mg/kg i.v. bolus and 50 mg/kg for the BS/ß-CD (n = 8/group), using a HPLCUV method specifically developed and validated. Individual plasma profiles obtained were evaluated by non-compartmental and compartmental approaches, using the software Scientist 2.0.1 (MicroMath®), analysis to determine the pharmacokinetic parameters. BS protein binding was determined by ultrafiltration at a concentration range of 1.0 a 60.0 µg/mL. BS tissue penetration after free or ß-CD-complexed drug administration was investigated in different tissues homogenates up to 5 h after i.v. bolus dosing of 10 mg/kg dose. Brain penetration of the free and complexed drug was also evaluated up to 4 h after administration of 50 mg/kg p.o. dose (3 animals/time point). Results and Discussion: BS free fraction in plasma was 34 ± 5%. The one-compartmental model described adequately the plasma profiles of all groups investigated. After i.v. (10 mg/kg) and p.o. (50 mg/kg) doses, pharmacokinetic parameters such as Vd (1.6 ± 0.5 e 2.2 ± 0.8 L/kg, respectively) and CLtot (1.4 ± 0.5 and 1.8 ± 0.5 L/h×kg, respectively) were higher for the BS/ß-CD than for the free drug, although the t1/2 (0.8 ± 0.1 h-1) remained the same (p < 0.05). The oral bioavailability of the BS/ß-CD (~ 37%) was approximately 2-fold of that observed for the free BS (~ 20%). The brain penetration factor after i.v. (2.8) and p.o. (2.5) doses, as well as the mean residence time, were higher after BS/ß-CD dosing than after free drug dosing, regardless of the route administrated. Conclusions: BS pharmacokinetics (free and complexed) showed a fast tissue distribution and elimination. The higher brain penetration of the drug after the administration of the complex reveals that the ß-CD may be a potential system to carrier, retain and change the delivery of BS in this organ, explaining the previous pharmacodynamic results.
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Lake, Fredrik. "C2- and C3-symmetric ligands via ring-opening of aziridines." Doctoral thesis, KTH, Chemistry, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3424.
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This thesis deals with the design and synthesis of chiralenantiopure nitrogencontaining ligands and the use of theseligands in asymmetric catalysis. A modular synthetic approachto enantiopure nitrogen-containing ligands was developed. Thesynthetic method is based on the ring-opening of activatedchiral aziridines by nitrogen nucleophiles. The aziridines areconveniently prepared from amino alcohols. The structure oftheaziridine and of the nucleophile can be extensively varied andlibraries of ligands are easily prepared. The use of primaryamines affords C2-symmetric bis(sulfonamides), whereas the use ofammonia affords C3-symmetric tris(sulfonamides) that can beelaborated into the corresponding tetra-amines.
The C2- and C3-symmetric ligands were used in the asymmetrictitaniummediated addition of diethylzinc to benzaldehyderesulting in modest enantioselection, 76% ee. A thoroughinvestigation of the reaction conditions revealed that theamount of Ti(OiPr)4has a decisive effect on the reaction rate and thestereochemical outcome of the reaction. The reaction timedecreased from about 90 hours to 15 minutes and theenantioselectivity changed from 26% of the (R)- enantiomer to72% of the (S)-enantiomer when the Ti(OiPr)4:benzaldehyde ratio was increased from 0.125:1 to1.48:1. Moreover, the titanium-mediated addition of diethylzincto benzaldehyde was studied in the presence of chiraladditives. The bis(sulfonamides) were also used in thecyclopropanation of cinnamyl alcohol. However, only lowenantioselection was observed, 27% ee.
The C3-symmetric tetra-amines were reacted to formazaphosphatranes. These weak acids were only partiallydeprotonated by the strong base KOtBu to form the correspondingproazaphosphatranes. The unexpectedly strong basicity of theproazaphosphatranes was believed to be due to steric effects assuggested by DFT calculations. The tetra-amines and thesulfonamides were used for the preparation of metal complexesof Lewis acidic metals such as titanium(IV) andzirconium(IV).
Keywords:asymmetric catalysis, aziridine, benzaldehyde,diethylzinc, enantioselective, ligand, proazaphosphatrane,ring-opening, sulfonamide, symmetry, titanium, zirconium
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Olceroglu, Ayse Hande. "Chiral Separations By Enzyme Enhanced Ultrafiltration: Fractionation Of Racemic Benzoin." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607460/index.pdf.
Full textAbstract:
In this study, a methodology for separation of chiral molecules, by using enhanced ultrafiltration system was developed. Benzoin was the model chiral molecule studied.
In the scope of developing this methodology, some parameters were investigated in the preliminary ultrafiltration experiments in order to set the operation conditions for enhanced ultrafiltration experiments. Due to the slight solubility of benzoin in pure water, 15% (v/v) Polyethylene glycol (PEG 400) and 30 % (v/v) Dimethyl sulfoxide (DMSO) were selected as cosolvents. Because of the high retention capacity of RC-10000 Da membranes for benzoin, a membrane saturation strategy was developed.
In polymer enhanced ultrafiltration (PEUF) experiments bovine serum albumin (BSA) was used as ligand. Effects of ligand concentration and pH on total benzoin retention and on enantiomeric excess (ee %) were investigated. Benzoin concentration was almost kept constant at ~10 ppm and ~50 ppm for 15% (v/v) PEG 400 and 30 % (v/v) DMSO cosolvents, respectively. It was observed that the increase either in pH or in BSA concentration yielded an increase in total benzoin retention. In 15% (v/v) PEG 400-water, with BSA concentration of 10000 ppm, at pH 10, total benzoin retention reached to 48.7%. For this cosolvent, at different pH values and at different BSA concentrations, all ee % values were about or less than 10%. When 50000 ppm BSA was dissolved in 30 % (v/v) DMSO-water, total benzoin retention increased to 41.3% at pH 10 and ee % reached 16.7 % at pH 11.
In enzyme enhanced ultrafiltration (EEUF) experiments, specific to benzoin, apo form of Benzaldehyde Lyase (BAL, E.C. 4.1.2.38) was used as ligand. These experiments were performed with constant ~ 10 ppm benzoin concentration in only 15% (v/v) PEG 400 &ndashwater solvent. Effect of BAL concentration on total benzoin retention and ee% was investigated. It was found that
for all the studied BAL concentrations in the range of 650- 1936 ppm total benzoin retention and ee % were kept almost constant at ~75% and ~60%, respectively.
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Leksawasdi, Noppol Biotechnology & Biomolecular Sciences (BABS) UNSW. "Kinetics and modelling of enzymatic process for R-phenylacetylcarbinol (PAC) production." Awarded by:University of New South Wales. Biotechnology and Biomolecular Sciences (BABS), 2004. http://handle.unsw.edu.au/1959.4/20846.
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R-phenylacetylcarbinol (PAC) is used as a precursor for production of ephedrine and pseudoephedrine, which are anti-asthmatics and nasal decongestants. PAC is produced from benzaldehyde and pyruvate mediated by pyruvate decarboxylase (PDC). A strain of Rhizopus javanicus was evaluated for its production of PDC. The morphology of R. javanicus was influenced by the degree of aeration/agitation. A relatively high specific PDC activity (328 U decarboxylase g-1 mycelium) was achieved when aeration/agitation were reduced significantly in the latter stages of cultivation. The stability of partially purified PDC and crude extract from R. javanicus were evaluated by examining the enzyme deactivation kinetic in various conditions. R. javanicus PDC was less stable than Candida utilis PDC currently used in our group. A kinetic model for the deactivation of partially purified PDC extracted from C. utilis by benzaldehyde (0?00 mM) in 2.5 M MOPS buffer has been developed. An initial lag period prior to deactivation was found to occur, with first order dependencies of PDC deactivation on exposure time and on benzaldehyde concentration. A mathematical model for the enzymatic biotransformation of PAC and its associated by-products has been developed using a schematic method devised by King and Altman (1956) for deriving the rate equations. The rate equations for substrates, product and by-products have been derived from the patterns for yeast PDC and combined with a deactivation model for PDC from C. utilis. Initial rate and biotransformation studies were applied to refine and validate a mathematical model for PAC production. The rate of PAC formation was directly proportional to the enzyme activity level up to 5.0 U carboligase ml-1. Michaelis-Menten kinetics were determined for the effect of pyruvate concentration on the reaction rate. The effect of benzaldehyde on the rate of PAC production followed the sigmoidal shape of the Monod-Wyman-Changeux (MWC) model. The biotransformation model, which also included a term for PDC inactivation by benzaldehyde, was used to determine the overall rate constants for the formation of PAC, acetaldehyde and acetoin. Implementation of digital pH control for PAC production in a well-stirred organic-aqueous two-phase biotransformation system with 20 mM MOPS and 2.5 M dipropylene glycol (DPG) in aqueous phase resulted in similar level of PAC production [1.01 M (151 g l-1) in an organic phase and 115 mM (17.2 g l-1) in an aqueous phase after 47 h] to the system with a more expensive 2.5 M MOPS buffer.
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Du, Guodong. "Group 4 Metalloporphyrin diolato Complexes and Catalytic Application of Metalloporphyrins and Related Transition Metal Complexes." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835301-irsXCw/webviewable/.
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Eriksson, Carina. "Isolation, Synthesis and Structure-Activity Relationships of Antifeedants against the Pine Weevil, Hylobius Abietis." Doctoral thesis, Stockholm Chemical Science and Engineering, KTH, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3919.
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Oliveira, Filho Jaires Gomes de. "Avaliação do papel repelente de voláteis isolados no odor de cães da raça Beagle contra o carrapato Rhipicephalus sanguineus (Acari: Ixodidae)." Universidade Federal de Goiás, 2014. http://repositorio.bc.ufg.br/tede/handle/tede/4117.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Ticks are arthropods of great importance in public health, due to the transmission of many pathogens. Rhipicephalus sanguineus parasites mainly dogs. It is known that Beagle dogs are less susceptible to R. sanguineus than English Cocker Spaniel, and still have resistance patterns linked to immunity. The lower susceptibility of Beagle dogs is due to chemical compounds they produce, which act in reducing the parasitic load of R. sanguineus on these animals. Given that this research aimed to verify the chemical repellency against R. sanguineus of compounds that have been identified in the odor of resistant dogs, and synthetic repellent compounds to other tick species. For testing chemical repellency two tests were used, the Petri dish and the Y-olfactometer. Five compounds identified in Beagle odors were selected and tested: 2 - hexanone, nonane, decane, undecane and benzaldehyde, the compound of botanical origin β-citronellol and the standard repellent DEET (N,N-diethyl-3-methylbenzamide). These compounds were tested alone and also two mixtures were evaluated: benzaldehyde and 2-hexanone (1:1), and benzaldehyde, 2-hexanone and undecane (1:1:1). All these compounds were prepared in a stock solution of 7.2 % ( ≈ 0.200 mg/cm²) and two lower concentrations were also tested: 0.100 and 0.050 mg/cm². DEET was repellent in the two highest concentrations and 68.33 to 86.67% of the ticks were found in untreated areas in different time points. At the concentration of 0.050 mg/cm² ticks were distributed similarly (without significant difference) in both areas. β-citronellol was the only compound tested that was repellent at all times and concentrations tested. The percentage of ticks in untreated areas ranged from 73.33 to 93.33 %. When compared β-citronellol with DEET the first compound was more effective at repelling the adults of R. sanguineus. For benzaldehyde, 30 minutes at a concentration of 0.200 mg/cm² a percentage of 63.33 % of ticks was observed in the untreated area. Percentage of 76.67 was observed after 5 min. at a concentration of 0.050 mg/cm². 2-hexanone was repellent at 30 min. at a concentration of 0.200 mg/cm² at 10 min. at a concentration of 0.100 mg/cm² and 30 minutes at a concentration of 0.050 mg/cm². For undecane a rate of 65.00% of ticks was observed in the untreated area in one moment of testing, the highest concentration during the first 5 min. of the evaluation. Nonane and decane not were not repellent at any of the concentrations and time intervals. The blend benzaldehyde + 2-hexanone was repellent in the three highest concentrations in almost all evaluated times, including in the olfactometer testing. During the whole test this mixture showed statistical similarity when compared with DEET. The addition of undecane to this blend did not potentiate its repellent power. The main result was the finding of natural repellents in resistant dogs to the tick R. sanguineus.
Carrapatos são artrópodes de grande importância dentro da saúde pública, devido à transmissão de inúmeros patógenos. Rhipicephalus sanguineus parasita principalmente cães. Sabe-se que cães da raça Beagle são menos susceptíveis ao R. sanguineus que cães Cocker Inglês, e ainda apresentam padrões de resistência ligados a imunidade. A menor susceptibilidade de cães Beagle está ligada a compostos químicos que estes produzem, os quais atuam na diminuição da carga parasitária de R. sanguineus sobre estes animais. Sabendo-se disso com esta pesquisa objetivou-se verificar a repelência química de compostos que foram identificados no odor de cães resistentes, além de compostos sintéticos repelentes para outros carrapatos, contra o R. sanguineus. Para os testes de repelência química foram utilizados dois ensaios de repelência, o da placa de Petri e do olfatômetro em Y. Foram testados cinco compostos com provável poder repelente e identificados nos odores de Beagle (2-hexanona, nonano, decano, undecano e benzaldeído), o composto de origem botânica β-citronelol e o repelente padrão DEET (N,N-dietil-3-metilbenzamida). Além destes compostos testados isoladamente, duas misturas foram avaliadas: benzaldeído e 2 -hexanona (1:1), e benzaldeído, 2-hexanona e undecano (1:1:1) Todos estes compostos foram formulados a partir de uma solução mãe de 7,2% (≈ 0,200 mg/cm²) da qual foi obtida posteriormente outras duas concentrações (0,100 e 0,050 mg/cm²). O DEET foi repelente nas duas maiores concentrações, sendo que 68,33 a 86,67% dos carrapatos foram encontrados nas áreas não tratadas, nos diferentes tempos de observação. Na concentração de 0,050 mg/cm² os carrapatos se distribuíram similarmente (sem diferença significativa) em ambas as áreas. β-citronelol foi o único composto testado que foi repelente em todos os tempos e concentrações testados. Os percentuais de carrapatos nas áreas não tratadas variaram de 73,33 a 93,33%. Quando comparado com o DEET o β-citronelol foi mais eficiente em repelir os adultos de R. sanguineus. Para o benzaldeido, aos 30 minutos, na concentração de 0,200 mg/cm² foi observado um percentual de 63,33% de carrapatos na área não tratada. Percentual de 76,67 foi observado aos cinco minutos, na concentração de 0,050 mg/cm². A 2-hexanona foi repelente aos 30 minutos, na concentração de 0,200 mg/cm², aos 10 minutos, na concentração de 0,100 mg/cm² e aos 30 minutos, na concentração de 0,050 mg/cm². Para o undecano foi observado um percentual de 65,00 de carrapatos na área não tratada em apenas um momento dos testes, na maior concentração, durante os primeiros cinco minutos de avaliação. Nonano e decano não causaram qualquer repelência para os carrapatos testados, em qualquer uma das concentrações ou intervalos de tempo avaliados. A mistura benzaldeido + 2-hexanona foi repelente nas três maiores concentrações, em quase todos os tempos avaliados, inclusive no teste de olfatometria. Durante todo o teste esta mistura mostrou semelhança estatística quando comparada com o DEET. A adição de undecano a esta mistura não potencializou o seu poder repelente. O principal resultado obtido foi a constatação da presença de repelentes naturais em cães resistentes ao carrapato R. sanguineus.
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Hess, Euodia. "Boron-doped Diamond Sensors for the Determination of Organic Compounds in Aqueous Media." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_5310_1305022937.
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In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively.
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SOARES, Paula Roberta Otaviano. "Atividade Antiproliferativa de Benzaldeído Canfeno Tiossemicarbazonas em Células de Melanoma Humano (SK-MEL-37)." Universidade Federal de Goiás, 2008. http://repositorio.bc.ufg.br/tede/handle/tde/1274.
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Previous issue date: 2008-05-21The thiosemicarbazones are chemical compounds of considerable scientific interest due to their important biological properties, such as antitumoral, antibacterial, antiviral, and antiprotozoal, among others. The studied compounds have the natural monoterpene camphene in the R4 position and the benzaldehyde in R2, with the substitution in the ring for different (R) groups, making this work unique. In this way, thirteen different compounds were derived from the benzaldehyde camphene thiosemicarbazone: camphene isotyiocyanate, camphene thiosemicarbazide, benzaldehyde camphene thiosemicarbazone, p-metyl benzaldehyde camphene thiosemicarbazone, p-methoxy benzaldehyde camphene thiosemicarbazone, o-chloro benzaldehyde camphene thiosecarbazone, m-chloro benzaldehyde camphene thiosemicarbazone, p-chloro-benzaldehyde camphene thiosemicarbazone, o-nitrobenzaldehyde camphene thiosemicarbazone, m-nitro- benzaldehyde camphene thiosemicarbazone, p-nitrobenzaldehyde camphene thiosemicarbazone, p-dimetylamino benzaldehyde camphene thiosemicarbazone and p-hydroxy benzaldehyde camphene thiosemicarbazone. The experiments were conducted in vitro using human melanoma cells (SK-Mel-37), because the melanoma is the most serious type of skin cancer due to its high possibility to metastasize and its resistance to the induction of apoptosis by antineoplastic drugs. We first performed a visual screening to observe if there was detachment of more than 85% of the total number of cells, after treatment with the sole concentration of 100 μM. Thus, six compounds were selected: benzaldehyde camphene thiosemicarbazone, m-chloro benzaldehyde camphene thiosemicarbazone, m-nitro-benzaldehyde camphene thiosemicarbazone, p-dimetylamino benzaldehyde camphene thiosemicarbazone, p-hydroxy benzaldehyde camphene thiosemicarbazone e p-methoxy benzaldehyde camphene thiosemicarbazone. The morphological analysis of the treated cells, by inverted phase contrast microscope and Giemsa stain, showed intense cellular vacuolization and nuclear fragmentation. In the cellular viability test, through the MTT colorimetric assay, the compounds showed IC50 (inhibitory concentration for 50% of the cells) values between 12, 84 μM and 32, 18 μM, which are bellow of those described in the literature for compounds with antineoplastic action. The analysis of nuclear fragmentation by fluorescence microscopy was performed by the incorporation of propidium iodide, and it was observed, at different time points, a progressive increase of cellular damage and a pronounced nuclear fragmentation after the cellular detachment. The analysis of the DNA fragmentation by agarose gel electrophoresis revealed that the unequivocal cytotoxic action of the compounds occurred by apoptosis. Our results showed that six compounds derived from the benzaldehyde camphene thiosemicarbazones had cytotoxic activity in human melanoma cells (SK-Mel-37) in vitro, and constitute potential candidates for future analysis aiming its therapeutic application.
As tiossemicarbazonas são compostos de considerável interesse científico devido às suas importantes propriedades biológicas, tais como antitumoral, antimicrobiana, antiviral, antiprotozoária, dentre outras. Os compostos estudados apresentam o monoterpeno natural canfeno na posição R4 e o benzaldeído em R2, com substituição no anel por diferentes grupos (R), o que confere ao presente trabalho um caráter inédito. Dessa forma, foram apresentados para este estudo onze diferentes compostos derivados de benzaldeído canfeno tiossemicarbazona: benzaldeído canfeno tiossecarbazona, p-metil benzaldeído canfeno tiossemicarbazona, p-metóxi benzaldeído canfeno tiossemicarbazona, o-cloro benzaldeído canfeno tiossemicarbazona, m-cloro benzaldeído canfeno tiossemicarbazona, p-cloro benzaldeído canfeno tiossemicarbazona, onitro benzaldeído canfeno tiossemicarbazona, m-nitro benzaldeído canfeno tiossemicarbazona, p-nitro benzaldeído canfeno tiossemicarbazona, p-dimetilamino benzaldeído canfeno tiossemicarbazona e p-hidróxi benzaldeído canfeno tiossemicarbazona, além de isotiocianato canfeno e canfeno tiossemicarbazida. Os experimentos foram realizados in vitro utilizando-se células de melanoma humano (SKMel- 37), visto que o melanoma é o tipo mais grave de câncer de pele devido à sua alta possibilidade de metástase e resistência à indução de apoptose por drogas antineoplásicas. Inicialmente, realizamos um screening visual observando-se o desprendimento de mais de 85% do total das células, após tratamento com a concentração única de 100 μM. Dessa análise, foram selecionados seis compostos: benzaldeído canfeno tiossemicarbazona, mcloro- benzaldeído canfeno tiossemicarbazona, m-nitro-benzaldeído canfeno tiossemicarbazona, p-dimetilamino-benzaldeído canfeno tiossemicarbazona, p-hidróxibenzaldeído canfeno tiossemicarbazona e p-metóxi benzaldeído canfeno tiossemicarbazona. A análise morfológica das células tratadas e coradas com Giemsa e observadas através de microscópio óptico invertido em contraste de fase demonstrou intensa vacuolização celular e fragmentação nuclear. Na análise da viabilidade celular, através do ensaio colorimétrico do MTT, os compostos apresentaram valores de IC50 (Concentração Inibitória para 50% das células) entre 12,84 μM e 32,18 μM, valores que se encontram abaixo do descrito na literatura para compostos com ação antineoplásica. A análise da fragmentação nuclear através de microscopia de fluorescência foi realizada pela incorporação de iodeto de propídio. Observamos, em diferentes tempos, o aumento progressivo dos danos celulares e a fragmentação nuclear pronunciada após o desprendimento das células. A análise de fragmentação de DNA por eletroforese em gel de agarose revelou de maneira inequívoca que a ação citotóxica observada ocorre por apoptose. Os resultados obtidos demonstraram que seis compostos derivados do benzaldeído canfeno tiossemicarbazonas apresentaram atividade citotóxica em células de melanoma humano (SK-Mel-37) in vitro, e são candidatos promissores para as análises futuras visando à sua aplicação terapêutica.
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Chausse, Jean-Pierre. "Etude par une methode de melange, de l'organisation et des conformations moleculaires dans les mesophases hautement ordonnees." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2E383.
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Etude des influences respectives des coeurs aromatiques et des chaines aliphatiques sur la nature du polymorphisme des cristaux liquides thermotropes. La methode de melange binaire consiste a etudier les modificaitons de l'organisation et du comportement moleculaire lorsque le milieu est perturbe par adjonction de molecules a chaines courtes parmi les molecules a chaines longues. Le melange de deux derives des bases de schiff, le 40. 2 et le 40. 8, en phase smectique b est essentiellement utilise. Techniques d'analyse : microscopie, diffraction rx, dilatometrie, spectre rmn du deuterieur et spectre rpe
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Hernández, Sánchez Karel. "Nuevas Aplicaciones de la L-Serina Hidroximetiltransferasa y la Benzaldehído Liasa en Síntesis Orgánica." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/285864.
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Las enzimas son importantes aliados en la síntesis de complejas moléculas orgánicas. Estos biocatalizadores ofrecen una elevada quimio, regio y estereoselectividad. Debido a esto se minimiza la formación de subproductos por reacciones competitivas no deseadas y se obtienen, por lo general, productos con una elevada pureza estereoquímica. Una especial atención, por sus aplicaciones en Química Orgánica, han recibido las enzimas que median la formación de enlaces C-C. Estas liasas catalizan la síntesis de moléculas complejas muchas de las cuales poseen variadas actividades biológicas. En el trabajo titulado: Nuevas Aplicaciones de la L-Serina Hidroximetiltransferasa y la Benzaldehído Liasa en Síntesis Orgánica se estudia las potencialidades de estos biocatalizadores en la síntesis de alfa,alfa-diarquía-alfa-aminoácidos, C-arilmonosacáridos y moléculas cíclicas derivadas del 7,8,14,15-tetrahidro-6H-dibenzo[f,j][1,5]dioxacicloundeceno a través de reacciones de carboligación. Para ello este estudio se ha dividido en 3 apartados:
APARTADO 3.1. Se muestra el diseño de nuevas variantes de la L-serina hidroximetiltransferasa de Streptococcus thermophilus (SHMTSth) que catalizan la síntesis de beta-hidroxi- alfa,alfa -dialquil-alfa-aminoácidos. Utilizando la ingeniería de proteínas y un diseño semirracional se incrementó la selectividad de la SHMTSth nativa hacia otros sustratos diferentes de la Gly. Por medio de esta metodología se encontraron tres variantes de la enzima, Y55T, Y55C y Y55S que catalizaron la adición aldólica de D-Ala y D-Ser a diferentes aldehídos. La SHMTSth Y55T resultó ser el biocatalizador más activo y permitió sintetizar beta-hidroxi- alfa,alfa -dialquil-alfa-aminoácidos con una elevada estereoselectividad (> 95 %).
APARTADO 3.2. En este apartado se describe como se acoplan las potencialidades sintéticas de una enzima tiamin dependiente con dos aldolasas a través de dos etapas químicas sencillas en la síntesis de C-arilmonosacáridos. La primera reacción enzimática consistió en la adición benzoínica cruzada de varios aldehídos aromáticos a dimetoxiacetaldehído, catalizado por benzaldehído liasa de Pseudomonas fluorescens biovar I (BAL). Esta reacción alcanzó conversiones superiores al 95 % y se realizó en un sistema tampón:MTBE (1:1 v/v) donde el producto se separó en la fase orgánica y se utilizó directamente en la siguiente etapa de síntesis. Posteriormente se redujeron las (R)-1-aril-2-hidroxi-3,3-dimetoxipropan-1-onas, utilizando NaBH4, con una elevada diastereoselectividad hacia la formación del diol anti (= 90 %). A continuación se hidrolizó el grupo acetal en medio ácido (H2SO4 2 M) y los (2S,3S) 3-aril-2,3-dihidroxipropanal obtenidos fueron utilizados en reacciones de adición aldólicas con diferentes sustratos dadores: dihidroxiacetona (DHA), hidroxiacetona (HA) y glicolaldehído (GO), catalizadas por D-fructosa-6-fosfato aldolasa (FSA) y sus variantes A129S y A129T respectivamente. Esto permitió sintetizar derivados de L-sorbosa (DHA), 1-desoxi-L-sorbosa (HA) y L-xilosa (GO). También se realizó la reacción de adición aldólica de DHA a los dihidroxialdehídos en tampón borato catalizado por L-ramnulosa-1-fosfato aldolasa (RhuA). Por medio de esta reacción se obtuvieron análogos de L-fructosa y L-tagatosa.
APARTADO 3.3 En esta sección se describe la adición benzoínica intramolecular catalizada por BAL. Con la síntesis de varios dialdehídos aromáticos se encontraron los requerimientos estructurales del sustrato para que la enzima catalizara la reacción de carboligación intramolecular. De los posibles sustratos ensayados, el 2,2'-(propano-1,3-diilbis(oxi))dibenzaldehído permitió obtener el ciclo (R)-15-hidroxi-7,8-dihidro-6H-dibenzo[f,j][1,5]dioxacicloundecen-14(15H)-ona como único productos en la reacción enzimática con conversiones superiores al 75 %. A partir de aquí se sintetizaron otros dialdehídos con los que sintetizaron análogos de 7,8,14,15-tetrahidro-6H-dibenzo[f,j][1,5]dioxacicloundeceno. De este estudio se determinó que la BAL cataliza reacciones de adición benzoínica intramolecular de aldehídos aromáticos unidos por una cadena espaciadora, propano-1,3-oxi, en posición 2,2´. La enzima también toleró sustituciones en posición 3,3´y 5,5´ del anillo aromático así como dialdehídos derivados de la piridina.Alpha,alpha-Disubstituted alpha-amino acids are central to biotechnological and biomedical chemical processes as their own sake and as substructures of biologically active molecules for diverse biomedical applications. Structurally, these compounds contain a quaternary stereocenter, which is particularly challenging for stereoselective synthesis. The pyridoxal 5’-phosphate (PLP)-dependent L-serine hydroxymethyltransferase from Streptococcus thermophilus (SHMTSth; EC 2.1.2.1) catalyzes the aldol addition reaction of Gly to aldehydes. We have developed by structure-based engineering a versatile SHMTSth biocatalyst with a wide spectrum of donor and acceptor selectivity overcoming the limitation of the native enzyme for Gly. We have constructed a SHMTSth variant that effectively accomplishes the stereoselective formation of quaternary stereocenters via aldol addition of D-Ala and D-Ser to a wide acceptor scope including aromatic, aliphatic aldehydes as well as hydroxy and nitrogen containing aldehydes to obtain a broad structural variety of alpha-methyl or alpha-hydroxymethyl,alpha-substituted alpha-amino acids. The “de novo” synthesis of carbohydrates and their derivatives (e.g. deoxysugars) is challenging due to the lengthy and time consuming cumbersome protective group strategies. Here, a highly expedient asymmetric synthetic route based on benzoin and aldol biocatalytic reactions for the preparation of new aryl carbohydrate derivatives is presented. The benzoin condensation of aromatic aldehydes to dimethoxyacetaldehyde catalyzed by benzaldehyde lyase from Psedomonas fluorescens biovar I, stereoselective reduction of the carbonyl group and acetal hydrolysis was then followed by the aldol addition of dihydroxyacetone, hydroxyacetone or glycolaldehyde catalyzed D-fructose 6-phosphate aldolase and L-rhannulose-1-phosphate aldolase. New intramolecular benzoin reaction was described using benzaldehyde lyase from Psedomonas fluorescens biovar I as biocatalyst. Different aromatic dialdehydes were tested and the 2,2'-(propane-1,3-diylbis(oxy))dibenzaldehydo yield cycle (R)-15-hydroxy-7,8-dihydro-6H-dibenzo[f,j][1,5]dioxacicloundecen-14(15H)-one as a single products (75 % conversion). Other dialdehydes analogs of A were synthesized and were obtained cycles derivate of 7,8,14,15-tetrahydro-6H-dibenzo[f,j][1,5]dioxaciclo undecene.
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Bidois, Séry Laure. "Nouvelle méthode d'accès aux composés aromatiques fluorés. Alkylations et aldolisations d'énolates préparés à partir d'énoxysilanes." Rouen, 1995. http://www.theses.fr/1995ROUES029.
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Le 3-méthyl-2,2,6,6-tétrachlorocyclohexanone a été cyclisé en milieu basique pour conduire à deux époxydes régioisomères avec un rapport 88/12. L'époxyde majoritaire est séparé de son régioisomère par chromatographie éclair sur silice. L'ouverture de l'époxyde majoritaire par l'éthérate de trifluorure de bore conduit de façon régio- et stéréosélective a une cis fluorhydrine. Une succession de cyclisation puis ouverture par les trihalogénures de bore permet la préparation d'halohydrines méthyles en position 3. Par oxydation et déshydrohalogénation des alcools, on accède aux crésols ortho, ortho' dihalogénés correspondants. Des cresols mono-halogénés (chloré ou fluoré) sont préparés à partir des époxydes intermédiaires. La coupure de la liaison oxygène-silicium des énoxysilanes tri- et tétrasubstitués de la 2-méthylcyclopentanone par t-BuOK conduit aux énolates tri- et tétrasubstitués correspondants. La méthylation de ces énolates conduit majoritairement a la 2,2-diméthylcyclopentanone. Ces énolates engagés dans des réactions d'aldolisation conduisant à des réactions en position 5. La 2-benzylidène-5,5-diméthylcyclopentanone a été ainsi préparée par coupure de l'énoxysilane tétrasubstitué de la 2-méthylcyclopentanone par t-BuOK suivie d'une aldolisation avec le benzaldéhyde. Après déprotonation par t-BuOK et alkylation par MeI, le composé a été obtenu avec un rendement global de 49% par rapport à l'énoxysilane de départ qui peut être constitué d'un mélange de régioisomères
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Hannachi, Hassen. "Etudes cinetiques sous conditions atmospheriques simulees des reactions de composes carbonyles avec oh', o::(3), no'::(3) : consequences sur la chimie de basse troposphere." Paris 7, 1986. http://www.theses.fr/1986PA077213.
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Huser, Marc. "Carbonylations catalytiques du chlorobenzene et du dichloromethane." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13196.
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"Bioprocess Operation Parameters For Benzaldehyde Lyase Production." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605242/index.pdf.
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Chen, Chien-Wen, and 陳建文. "Hydroxyamide-catalyzed Enantioselective Addition of Diethylzinc to Benzaldehyde." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/64752528846616315693.
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碩士朝陽科技大學
應用化學系碩士班
97
Using a variety of chiral catalysts prepared from (+)-pinene, the asymmetric addition of diethylzinc to aromatic aldehydes was investigated. At various temperatures, different solvents and various amounts of chiral catalysts were attempted. The best reaction condition involved n-hexane as a solvent, at -15°C and 20 mol % of chiral catalyst. Asymmetric addition of diethylzinc to aromatic aldehydes producing optical active alcohols, resulting in the enantioselectivity from 0 % to 62 % ee. The yields were from 37 % to 93 %. Most importantly, mono- amide catalysts exhibited higher enantioselectivity, while the C2- symmetric amides exhibited lower selectivity. And we found that the reaction with the addition of titanium, seemingly have lower enantioselectivity in the range of 9-14 % ee.
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"Metal catalyzed air oxidation of toluene for the production of benzaldehyde, benzyl alcohol and benzoic acid-process improvement." Chinese University of Hong Kong, 1991. http://library.cuhk.edu.hk/record=b5886872.
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by Yam Chi Ming.Thesis (M.Phil.)--Chinese University of Hong Kong, 1991.
Bibliography: leaves 132-135.
TABLE OF CONTENTS
DESCRIPTIVE NOTE PAGE
ABSTRACT --- p.iii
ACKNOWLEDGEMENTS --- p.v
Chapter CHAPTER ONE： --- BACKGROUND SURVEY OF THE CHEMISTRY OF THE OXIDATION OF ORGANIC COMPOUNDS --- p.1
Chapter 1.0 --- Introduction --- p.1
Chapter 1.1 --- Catalytic Oxidation of Toluene --- p.4
Chapter 1.1.1 --- Metal-catalyzed Air Oxidation of Organic Compounds --- p.4
Chapter 1.1.2 --- Metal-catalyzed Air Oxidation of Alkyl-Aromatic Compounds --- p.11
Chapter 1.1.3 --- Cobalt-catalyzed Air Oxidation of Toluene --- p.12
Chapter 1.2 --- Industrial Metal-catalyzed Air Oxidation of Toluene --- p.13
Chapter 1.3 --- Scope of this Thesis --- p.16
Chapter CHAPTER TWO： --- EXPERIMENTAL --- p.20
Chapter 2.1 --- Reactor System Description --- p.20
Chapter 2.1.1 --- Liquid Sampling Unit --- p.23
Chapter 2.1.2 --- Gas and Reagent/Catalyst Inlet --- p.23
Chapter 2.1.3 --- Recycling Unit --- p.26
Chapter 2.1.4 --- Vapour Disposal --- p.28
Chapter 2.2 --- Practical Operation Consideration --- p.30
Chapter 2.3 --- Process (Experimental) Parameter Control --- p.33
Chapter 2.3.1 --- Gas Inlet and Input Pressure Control --- p.33
Chapter 2.3.2 --- Gas Outlet and System Pressure Control --- p.34
Chapter 2.3.3 --- System Temperature Control --- p.35
Chapter 2.4 --- Data Acquisition --- p.36
Chapter 2.5 --- Experimental Procedures --- p.38
Chapter 2.5.1 --- Initial Operation Testing --- p.38
Chapter 2.5.2 --- General Procedures --- p.38
Chapter 2.5.3 --- Experimental Conditions --- p.41
Chapter 2.5.3.1 --- Air Oxidation of Toluene --- p.41
Chapter 2.5.3.2 --- Cobalt-catalyzed Air Oxidation of Toluene --- p.43
Chapter 2.5.3.3 --- Silver-catalyzed Air Oxidation of Toluene --- p.47
Chapter 2.5.3.4 --- Cobalt-Silver Co- catalyzed Air Oxidation of Toluene --- p.47
Chapter 2.5.3.5 --- Hydrogen Peroxide Experiment --- p.47
Chapter 2.6 --- Reactor Product Analysis --- p.48
Chapter 2.6.1 --- Liquid Sample Analysis --- p.48
Chapter 2.6.2 --- Cobalt (II)Analysis --- p.49
Chapter 2.7 --- Product Identification and Confirmation by 1H Nuclear Magnetic Resonance --- p.56
Chapter CHAPTER THREE： --- RESULTS AND DISCUSSIONS --- p.58
Chapter 3.0 --- Introduction --- p.58
Chapter 3.1 --- Air Oxidation of Toluene --- p.60
Chapter 3.2 --- Cobalt-catalyzed Air Oxidation of Toluene --- p.75
Chapter 3.3 --- Silver-catalyzed Air Oxidation of Toluene --- p.96
Chapter 3.4 --- Cobalt-Silver Co-catalyzed Air Oxidation of Toluene --- p.106
Chapter 3.5 --- Industrial Applications --- p.116
Chapter CHAPTER FOUR： --- CONCLUSION --- p.126
BIBLIOGRAPHY --- p.132
Chapter APPENDIX I --- Computer Program for the Integrator --- p.136
Chapter APPENDIX II --- Raw Data for the Experimental Runs --- p.140
Chapter APPENDIX III --- Raw Data for Different Trials of Run #11 --- p.160
Chapter APPENDIX IV --- "Raw Data for the Calibration of Benzaldehyde, Benzyl Alcohol, Benzoic Acid, Benzyl Acetate, Benzyl Benzoate and Cobalt (II)" --- p.161
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Lin, Sheng-Yi, and 林聖壹. "Thermokinetics Estimation on α-methylstyrene and trans-β-methylstyene with Benzaldehyde." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/85652782413053927784.
Full textAbstract:
碩士雲林科技大學
環境與安全工程系碩士班
96
Styrene monomer (SM) is widely used in petrochemical industries and it becomes a necessary material in daily life. SM may mixing with oxygen to oxidize as benzaldehyde in storage circumstance. Benzaldehyde was contacted with SM and its derivatives that involves α-methylstyrene (AMS) and trans-β-methylstyrene (TBMS) to confer reaction in exothermic runaway behaviors. Differential scanning calorimetry (DSC) and thermal activity monitor Ⅲ (TAM Ⅲ) were employed to determine the thermokinetics and safety index of AMS and TBMS mixed with benzaldhyde, respectively. The exothermic onset temperature (T0) occurred at high temperature and the total heat of reaction (Qtotal) was increasing in styrene comparing with benzaldehyde solutions. The above reaction did not result in potential thermal hazards in the polymerization process, except for degrading its product quality.
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Liu, Cheng-Hong, and 劉正宏. "Preparation and Spectroscopic Study of Benzaldehyde hydrazone and Bis-benzylidene hydrazine." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/56476945110230007267.
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碩士靜宜大學
應用化學研究所
91
The benzaldehyde hydrazones can be prepared by heating a ethyl alcohol solution containing aryl aldehyde and tenfold hydrazine for three hours. The bis-benzylidene hydrazine can be prepared by heating a ethyl alcohol solution containing isometric aryl aldehyde and hydrazine for an hour. The hydrazone of aryl aldehydes are very unstable except nitro-benzaldehyde hydrazone. A series of benzaldehyde hydrazones and bis-benzylidene hydrazines for the study on the substituent- induced chemical shifts (SCS) of Cα using the 13C NMR spectral analyses. The correlation between SCS and Hammett constants (σ) shows that the substituent effect via inductive effect for Cα ( slope=-4.01, r2=0.939). No correlation can be made for the bis-benzylidene hydrazine. A series of benzaldehyde hydrazones for the study on the chemical shifts of N using the 15N NMR spectral analyses, the correlation between chemical shifts and Hammett constants (σ) shows that the substituent effect via inductive effect for the amino N(slope=3.89, r2=0.814。) and the imino N (slope=13.36, r2=0.940)
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Chen, Yen-min, and 陳彥閔. "Study on the Addition Reaction of [3.2.1] Bicyclic Allylboronates with Benzaldehyde." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/53s7u7.
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碩士朝陽科技大學
應用化學系碩士班
96
Alkylation chemistry is one the useful tools in organic synthesis. For example, allylboronates, as nucleophile donors, react with the aldyhyde, to provide sec-alcohol with high stereoselectivity. In fact, allylboronates are chiral auxiliaries either. In this study, inexpensive and easy obtained natural camphor was chosen as an initiator for the reaction to form allylboronate. After reacting with various alkyl magnesium halides (RMgX), ring expansion and stereoselective product - [3.2.1] bicyclic octanediol was formed. The novel products, allylboronate compounds , were then generated by boronylation of the [3.2.1] bicyclic octanediol . Allylboronates provide allyl group for addition under the various Lewis acid catalysis with the benzaldehyde, the yield and the enantiomeric excess of products were also studied.
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Lin, Chia-Shi, and 林家旭. "Synthesis and Reactivities of Chromium Group Complexescontaining 2-(Diphenylphosphino)benzaldehyde Ligand." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/50513930136882717895.
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Yang, Jing-wen, and 楊靜雯. "Synthesis of W(CH3CN)(PhC≡CPh)3 with 2-(Diphenylphosphino)benzaldehyde Ligand." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/51181806193201749313.
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Tseng, Min-Chia, and 曾敏佳. "Enantioselective Addition of Diethylzinc to Benzaldehyde Using Pinene Derived Amino Alcohols as Catalysts." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/55252656164148166451.
Full textAbstract:
碩士朝陽科技大學
應用化學系碩士班
97
In thesis a study, we used natural (+)-α-pinene as a starting material to synthesize a series of novel N-substituted aminoalcohols. These aminoalcohols have been used as catalysts for the enantioselective addition reaction of diethylzinc to benzaldehyde. We have found that different aminoalcohols may catalyze the addition reaction to obtain various ratio of enantiomers, albeit that the enantioselectivity is not as high as what we expected.
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Wu, Ming-Ju, and 吳銘儒. "Study Effect of Reaction Condition on o-Phenylenediamine and Benzaldehyde by VESI/MS." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/39968891871777057177.
Full textAbstract:
碩士國立高雄大學
應用化學系碩士班
104
Benzimidazole compound synthesis reactions have been many studies, however, these studies have focused on offline in order to explore the selective product. In this study, the use of Venturi Electrospray Ionization Mass Spectrometry ( VESI-MS) for online real-time analysis, change trend generate major component observation o-phenylenediamine and benzaldehyde under different synthesis conditions benzimidazole, discussion reaction conditions included changing the solvent, the substituents o-phenylenediamine and benzaldehyde on acid catalysis conditions. Methanol as solvent, displayed within 60 minutes of the observation time is gradually reduced after the intermediate product quickly generate, along with the mono-substituted product is increased, di-substituted product will not change significantly. When changed to ethanol and water as a solvent, change trend of the various components will be different, but the intermediate change in water no too much. When the BA of number 4 carbon positions at different substituents replacement, -CN and -Cl electron-withdrawing substituents can inhibit the synthesis reaction, and the inhibitory effect -CN group is stronger than the -Cl group. Instead, electron-donating substituents -CH3 can accelerate the reaction. If o-PD of –H on the 4th carbon position replace with –CH3, it will slow down the rate of reaction. When o-PD and CH3-BA reaction, the carbon on the 4th replace on the 3rd -CH3 change on carbon, can also cause changes in the rate of formation of the intermediate product. Adding an acid to o-PD and CN-BA reaction solution can significantly increase the rate of reaction, trifluoroacetic acid (TFA) to accelerate the reaction rate is better than the effect of acetic acid, but TFA and CN-BA will be side effects. This study successfully demonstrated VESI-MS can be used as real-time changes in the components of online instant detection of benzimidazole synthesis, results show that solvent, substituent, acid will affect the reaction rate. A compound of changes observed in this study was based on intensity change in a particular ion mass spectrum, it does not represent the actual yield of the compound, and therefore can not directly affect the results of the comparison with the known synthetic conditions on the product selectivity to do
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Patel, Ranjita, and Soubhagyabati Sahoo. "Effect of Solvent on Azo-Hydrazonetautomerism of 2-Hydroxy-5-(4-Nitrophenylazo) Benzaldehyde." Thesis, 2015. http://ethesis.nitrkl.ac.in/7262/1/2015_Effect_Patel_and_Sahoo.pdf.
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Azo dye has been synthesized having Donor-p-Acceptor (D-p-A) system to study the effect of solvent on the azo-hydrazone tautomerism. The relative stabilities of azo and hydrazone tautomer are examined by means of UV-Vis spectroscopic technique and are correlated with the solvent properties in neat organic solvents and in different binary solvent mixture. Due to the presence of intramolecular H-bonding, azo form predominates in most of the nonpolar and polar protic solvents. Presence of low energy CT band in basic solvents like DMF is due to the predominance of anionic hydrazone form stabilized through the lengthening of the conjugated system. In the binary solvent mixtures, preferential solvation occurs due to specific solute-solvent interaction. The microenvironment surrounding the dye molecules played a major role in the stability of one tautomer relative to the other.A good understanding of the properties of specific azo dyes in different medium lead to the design of new azo dye molecules with targeted properties for applications in specific areas.
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Ashley, Melissa Ann. "Photoredox-Catalyzed Site-Selective Functionalization of Primary Amine Derivatives." Thesis, 2021. https://doi.org/10.7916/d8-nz4d-fj65.
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Given the prevalence of primary amines in biologically active molecules, an important area of research is devoted to creating methods to site-selectively functionalize their C(sp³)-H bonds. For simple aliphatic primary amines, many of these C-H bonds are chemically indistinguishable due to their similar electronics and sometimes, steric environments. Through strategic choice of activating group, site-selective functionalization at both α- and ẟ- positions is achieved. Exploiting inductive effect allows for a photoredox-catalyzed α-C(sp³)-H alkylation of trifluoromethanesulfonamides. In the case of trifluoroacetamides, functionalization is directed to a distal C(sp³)-H site via [1,5]-hydrogen atom transfer which results in a formal delta-aminomethylation and delta-cyanation. Lastly, by subjecting primary amines to an electron-rich benzaldehyde activating group, we leverage C-N bonds as a functional handle for deaminative radical cross-couplings.
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Lin, Ying-Cheng, and 林穎成. "P3HT/TiO2 nanocomposite based on benzaldehyde end-functionalized P3HT and amphiphilic P3HT block copolymer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/12384344491639221951.
Full textAbstract:
碩士國立臺灣大學
材料科學與工程學研究所
102
In this thesis, we reported the preparation, the microstructures and the optical properties of poly(3-hexylthiophene)/TiO2 nanocomposites based on aldehyde end-functionalized P3HT (P3HT-CHO) and amphiphilic P3HT block copolymer, poly(3-hexylthiophene-block-hydroxylated isoprene) (P3HT-b-PIOH). Pristine unmodified P3HT were also used for reference studies. Two methods were employed to prepare the Nanocomposites: (1) solution blending of polymers and commercial available TiO2 nanoparticles, Degussa P25 (~21 nm); (2) in-situ sol gel process of TiO2 precursors in polymer solution. The attractive interaction between aldehyde of P3HT-CHO and hydroxyl group of TiO2 allowed smaller aggregations of TiO2 (~ 50 - 200 nm) blending.The in-situ sol gel processes using chlorotitanium triisopropoxide (ClTIP) would further enhance the homogeneity in TiO2 dispersion despite of enlarged particle sizes (~ 50 -200 nm) as the aldehyde group of P3HT-CHO would react with ClTIP to form covalent bonds to anchor P3HT in the surface of TiO2. Thus preventing the aggregation of TiO2. Since the in-situ sol gel process avoid the use of dispersants and ligands of TiO2 nanoparticles, the photoluminescence quenching of P3HT-CHO/ClTIP composites could be further improved comparing to P3HT-CHO/P25. The use of amphiphilic P3HT-b-PIOH block copolymer remarkably afforded the resulting P3HT-b-PIOH/ClTIP composites having uniformed TiO2 nanoparticles (~ 30 nm) homogenously dispersed in the polymer matrix, which could be attributed the increasing number of covalent linkages between the hydroxyl groups of PIOH and ClTIP. The optical properties were derived from the UV-vis spectroscopy. Even the loading of TiO2 was up to 30 wt%, the maximum absorption peak was not blue-shifted and the π-π stacking of P3HT retain for P3HT-CHO/ClTIP and P3HT-b-PIOH/ClTIP composites
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Chang, Hui-Wen. "Synthesis, Electrochromic and Photochromic Properties of Novel Aromatic Polymers from Benzaldehyde and Triphenylamine Derivatives." 2008. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0020-2608200822285300.
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