Dissertations / Theses: 'Cyanohydrine'

1

Carta, Paola. "Synthesis and applications of chiral cyanohydrins." Thesis, King's College London (University of London), 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414006.

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Wingstrand, Erica. "New Methods for Chiral Cyanohydrin Synthesis." Doctoral thesis, KTH, Kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10205.

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This thesis deals with method development in asymmetric catalysis and specifically syntheses of enantioenriched O-functionalized cyanohydrins. The first part describes the development of a method for the synthesis of O‑alkoxycarbonylated and O-acylated cyanohydrins. Ethyl cyanoformate and acyl cyanides were added to aldehydes in a reaction catalyzed by a chiral dimeric Ti-salen complex together with a tertiary amine. High yields and enantioselectivities were in most cases obtained. Mechanistic studies were performed and a reaction mechanism was proposed. The second part describes a method in which the undesired minor enantiomer in a Lewis acid–Lewis base-catalyzed acylcyanation is continuously recycled into prochiral starting material. Close to enantiopure O‑acylated cyanohydrins were obtained in high yields. The third part deals with asymmetric acylcyanations of ketones. Acetyl cyanide was found to add to α‑ketoesters in a reaction catalyzed by a chiral Lewis base. Yields up to 77% and 82% ee were obtained. The final part describes an enzymatic method for high-throughput analysis of O‑acylated cyanohydrins. The enantiomeric excess and conversion were determined for products obtained from a number of aromatic and aliphatic aldehydes.
QC 20100818

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Hogg, David Joseph Philip. "Mechanistic studies on asymmetric cyanohydrin synthesis." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262128.

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4

Lundgren, Stina. "Efficient Synthesis and Analysis of Chiral Cyanohydrins." Doctoral thesis, Stockholm : Kungliga Tekniska högskolan (KTH), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4315.

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5

Young, Carl. "Asymmetric cyanohydrin synthesis using heterobimetallic salen complexes." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500998.

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Asymmetric cyanohydrin synthesis is a broad and developing area of organic chemistry to which many groups have contributed over the years. Notably, North et al have developed highly active salen based catalysts 1 and 2 for the asymmetric addition of cyanide to aldehydes. More recent mechanistic investigations have revealed that combining complexes 1 and 2 gave interesting results indicating the possible formation of and catalysis by a new heterobimetallic complex formed in-situ. This thesis follows on from the initial study and offers good evidence for the formation of a mixed metal bimetallic catalyst possessing characteristics of each parent complex. Firstly, the catalysed addition of trimethylsilyl cyanide, potassium cyanide and ethyl cyanoformate to benzaldehyde was studied (Scheme 1) using various chiral and achiral analogues of complexes 1 and 2 to study the effects on cyanohydrin product enantiometric excess and absolute configuration.

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Heid, Berenice. "Enantioselective Preparation of ω-Functionalized O-Acylated Cyanohydrins." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-40896.

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A minor enantiomer recycling one-pot process usingω-functionalized prochiral aldehydes as starting materials and two reinforcing catalysts has been reported. The desired aldehyde for these process studies was 5-bromo-1-pentanal. In a two-phase solvent system, enzyme-catalyzed hydrolysis of the minor enantiomer regenerates continuously the prochiral starting material and Lewis acid catalysed addition of acetyl cyanide provides the O-acetylated cyanohydrins. The minor enantiomer recycling process has been studied and improved for 5-bromo-1-pentanal to receive high enantiomeric excess and yield of the expected O-acetylated cyanohydrin.

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Clutterbuck, Lisa. "The catalytic, asymmetric synthesis of cyanohydrins and amino nitriles." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505844.

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Gregory, Robert John Hryntchyshyn. "Biocatalytic preparation and chemistry of some novel cyanohydrin systems." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365896.

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Ahmed, Takiya Janice. "The role of bone morphogenetic proteins in otic specification /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2008. http://hdl.handle.net/1794/8447.

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Thesis (Ph. D.)--University of Oregon, 2008.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 195-204). Also available online in ProQuest, free to University of Oregon users.

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Briechle, Sebastian Dirk [Verfasser], and Andreas [Akademischer Betreuer] Liese. "Stereoselective synthesis of cyanohydrins: process development / Sebastian Dirk Briechle. Betreuer: Andreas Liese." Hamburg-Harburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2013. http://d-nb.info/1048574067/34.

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Briechle, Sebastian Dirk Verfasser], and Andreas [Akademischer Betreuer] [Liese. "Stereoselective synthesis of cyanohydrins: process development / Sebastian Dirk Briechle. Betreuer: Andreas Liese." Hamburg-Harburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2013. http://nbn-resolving.de/urn:nbn:de:gbv:830-tubdok-12054.

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Knapp, Spring Melody, and Spring Melody Knapp. "Investigation of Secondary Coordination Sphere Effects for Cyanohydrin Hydration with Transition Metal Catalysts." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12362.

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The synthesis of high value acrylic monomers is currently done industrially via cyanohydrin hydration using concentrated acids, resulting in large quantities of useless byproducts. This current process is energy intensive and lacks atom economy; therefore, alternative cyanohydrin hydration strategies are under investigation. Ideally, cyanohydrin hydration would be done using organometallic nitrile hydration catalysts. Cyanohydrin hydration with these catalysts is challenging, because it needs to be done at low temperatures and under acidic conditions to reduce cyanohydrin degradation and catalyst poisoning with cyanide. This dissertation describes the reactivity of [Ru(#951;
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Downs, Emma. "An Investigation of Transition Metal Catalysts for Cyanohydrin Hydration: The Interface of Homogeneous and Heterogeneous Catalysis." Thesis, University of Oregon, 2014. http://hdl.handle.net/1794/18348.

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Acrylic monomers are important materials that represent a large portion of the economy. The current industrial synthesis hydrates cyanohydrins with sulfuric acid, a process which results in large amounts of waste and significant energy costs. A transition metal catalyzed, acid free hydration of cyanohydrins would be beneficial from both economic and environmental standpoints. However, this reaction is challenging, as many catalysts are poisoned by the cyanide released when cyanohydrins degrade. Therefore the development of a catalyst that is resistant to cyanide poisoning is the ideal method to circumvent these difficulties. This dissertation describes several cyanohydrin hydration catalysts, with an emphasis on nanoparticle catalysts. These are at the interface between the homogeneous and heterogeneous catalysts that have been explored previously for this reaction. Chapter I surveys previous studies on nanoparticle catalysts for nitrile hydration and their implications for the hydration of cyanohydrins. Chapter II reports on the homogeneous platinum catalysts [PtHCl(P(NMe2)3)2] and [PtH2(P(NMe2)3)2], exploring secondary coordination sphere effects to enhance nitrile hydration. Chapter III describes another example of this type of complex, [PtH2(P(OMe)3)2], that forms catalytically active nanoparticles under reaction conditions. Explorations of the reactivity of this catalyst with nitriles and cyanohydrins are also described in this chapter. Chapter IV investigates a silver nanoparticle catalyst with a water soluble phosphine (1,3,5-triaza-7-phosphaadamantane) ligand for its activity towards the hydration of nitriles and cyanohydrins. The results of the degradation of the nanoparticles in the presence of cyanide are also described. Chapter V reports on the preparation and examination of a solid supported nickel catalyst for cyanohydrin hydration. Finally, Chapter VI describes how these investigations have made progress towards the development of a cyanide resistant nitrile hydration catalyst. This dissertation includes previously published and unpublished co-authored material.
2015-09-29

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Ahmed, Takiya Janice 1980. "Investigations of transition metal catalysts for the hydration of cyanohydrins and ligand effects in aqueous molybdocene chemistry." Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/8447.

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xx, 204 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.
Efforts toward developing improved methods of synthesizing acrylamides are ongoing. Several homogeneous organometallic and coordination complexes have proven useful in catalytic acrylonitrile hydration; however, none of these complexes have been tested in the hydration of cyanohydrins used to synthesize substituted acrylamides. This dissertation describes the reactivity of molybdocene and Pt phosphinito nitrile hydration catalysts toward cyanohydrin substrates and the effect of Cp ring substituents on aqueous molybdocene chemistry. Chapter I identifies the motivation for developing a transition metal-catalyzed process for cyanohydrin hydration and the strategy used to improve on the reactivity of molybdocene catalysts. Chapter II reports the effect of cyclopentadienyl ring substituents on the electronic and geometric structure, solution behavior, and hydrolytic activity of molybdocenes. To examine the effect of Cp ring substituents, ansa -molybdocenes containing the fragment {C 2 Me 4 (C 5 H 4 ) 2 }Mo 2+ were compared to non-bridged molybdocenes containing (C 5 H 5 ) 2 Mo 2+ and (C 5 H 4 Me) 2 Mo 2+ . Addition of a tetramethylethylene-bridge decreases the electron density on the Mo center and exerts a small effect on the structure of the metallocene. However, the catalytic activity of the molybdocene catalysts is unchanged or slowed because of counteractive effects on the bound nucleophile and electrophile. Although adding substituents to the Cp rings did not change the catalytic activity of the molybdocene, the substituents led to significant changes in the equilibrium behavior. The equilibria have practical consequences that warrant investigation. Chapters III and IV chronicle the effect of Cp ring substituents on the monomer-dimer equilibria and the acidity of the molybdocene complexes, respectively. Interestingly, the monomer-dimer equilibrium established by ansa -{C 2 Me 4 (C 5 H 4 ) 2 }Mo(OH)(OH 2 ) + exhibits a strong solvent dependence. New equilibrium schemes are reported for the ansa and non- ansa complexes. Chapter V describes the reactivity of the molybdocene and Pt phosphinito catalysts toward cyanohydrins. Both catalysts gave unsatisfactory results; however, the Ã Ã Ã Ã Ã Â±-hydroxy substituent of cyanohydrins facilitates nitrile hydration. The low reactivity exhibited by these systems was due to liberation of hydrogen cyanide from the cyanohydrin leading to acute poisoning of either catalyst. As discussed in Chapter VI, this study will expedite the innovation of new catalysts that are better suited to overcome the challenges associated with cyanohydrin hydration. This dissertation includes previously published and unpublished co-authored material.
Adviser: David R. Tyler

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15

Castelló, Micó Alicia [Verfasser], and Paul [Akademischer Betreuer] Knochel. "Organometallic reagents of Lithium, Magnesium, Zinc and Zirconium for the functionalization of aromatics, S-heterocycles and silylated cyanohydrins / Alicia Castelló Micó ; Betreuer: Paul Knochel." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1143518772/34.

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16

Laurell, Nash Anna. "Development and Studies of the Processes Involved in Minor Enantiomer Recycling." Doctoral thesis, KTH, Organisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156635.

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This thesis describes the development and rationalization of processes involved in a new methodology developed in our group, minor enantiomer recycling. The first part of the thesis addresses mechanistic studies of one of the reactions involved in minor enantiomer recycling, dual Lewis acid-Lewis base catalyzed acetylcyanation of aldehydes. The methodology uses a combination of a chiral titanium-salen complex with a tertiary amine as a catalytic system in the enantioselective synthesis of O-acylated cyanohydrins from aldehydes and ketonitriles. Mechanistic investigations revealed that the rate-determining step in the reaction changes, depending on the nature of the aldehyde that was used. It was also concluded that cyanohydrin is coordinated to the Lewis acid in the acylation step. The second part of the thesis deals with minor enantiomer recycling, a highly selective one-pot recycling system. In a first step the product is formed as a minor and a major enantiomer by asymmetric catalysis. Recycling of the minor enantiomer, by selective kinetic resolution, regenerates the starting material. Continuous addition of a second reagent, also involved in a coupled exergonic process, leads to an increase of both yield and enantiomeric excess. Recycling procedures for the synthesis of O-acylated and O-formylated cyanohydrins have been developed with high yield and high enantiomeric excess of the products. The study includes development of the systems, comparison to other methodologies in asymmetric catalysis, and attempts to understand the processes involved.

QC 20141202

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17

Stokoe, Robert B. "Conformational and mechanistic studies on asymmetric cyanohydrin synthesis : an analysis of the dipeptide catalysts cyclo-[(S)-His-(S)-Phe], cyclo-[(S)-His-(S)-Leu] and related compounds." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320398.

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18

Saglam, Guluzar. "Synthesis Of Novel Chiral Thiourea Derivatives And Their Applications, Synthesis Of Some Hdac Inhibitors, Addition Of Acyl Phosphonates To Ethylcyanoformate." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609265/index.pdf.

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The thiourea derivatives have become a main focus of research in asymmetric synthesis as an organocatalyst in recent years. In the first part, the thiourea catalysts are synthesized starting from easily available L-tartaric acid and application of the catalysts to some addition reactions showed no significant asymmetric induction. A number of HDAC inhibitors have been developed as anti-cancer agent at the present time.In the second part, some aryl butenoic acid derivatives are synthesized as HDAC inhibitors starting from substituted benzaldehyde and pyruvic acid. The HDAC activity studies showed comparable results with known molecules. In the last part, some acyl phosphonates are synthesized and addition of ethylcyanoformate to acyl phosphonates furnished the products in good yields.

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19

Reis, Barbaros. "Addition Of Acyl Phosphonates To Ethylcyanoformate." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609090/index.pdf.

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Functionalized cyanophosphates are important starting materials for the synthesis of beta-lactam ring moiety of beta-lactam antibiotics. The cyanophosphates are synthesized starting from easily available acylphosphonate and ethylcyanoformate. Acylphosphonates are synthesized starting from acylchloride and trimethylphosphite. Addition of acylphoshonate to ethylcyanoformate furnishes the cyanophosphate with the quaternary center.

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20

Boukattaya, Fatma. "Addition d'organomagnésiens sur des nitriles fonctionnalisés : application à la synthèse de molécules d’intérêt biologique." Thesis, Le Mans, 2016. http://www.theses.fr/2016LEMA1007.

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L’addition nucléophile des réactifs de Grignard sur les nitriles conduit généralement aux cétones après hydrolyse acide. La double addition, menant à des carbinamines tertiaires après traitement, est beaucoup plus difficile et ne s’effectue habituellement qu’avec les organomagnésiens allyliques. Dans ce contexte, nous avons découvert que les organomagnésiens peuvent effectuer une double addition sur la fonction nitrile des acylcyanhydrines, pour fournir des hydroxyamides. Cette réaction est originale par le fait qu’une large gamme d’organomagnésiens peut être utilisée, dans des conditions particulièrement douces. Cette réaction a été appliquée à la synthèse de différents acides α-aminés α,α-disubstitués, par oxydation de la fonction alcool et hydrolyse du motif amide. La divinylglycine a notamment pu être préparée avec un bon rendement. L’addition successive de deux organomagnésiens différents a aussi pu être réalisée, après optimisation des conditions de réaction, pour accéder à des hydroxyamides disymétriques, précurseurs d’acides aminés quaternaires chiraux. Enfin, l’addition des réactifs de Grignard sur les 3-cyano iminocoumarines N-éthoxycarbonylées a été étudiée. Malgré la présence de nombreux sites électrophiles, la réaction est très chimiosélective, et des chromènes originaux substitués en position 4 ont été obtenus. Les propriétés antifongiques et antibactériennes de ces derniers ont été évaluées
The nucleophilic addition of Grignard reagents on nitriles generally leads to ketones after acidic hydrolysis. The double addition, providing tertiary carbinamines after work-up, is more difficult and usually occurs only with allylic Grignard reagents. In this context, we discovered that Grignard reagents can perform a double addition on the nitrile function of acyl cyanohydrins, to provide hydroxyamides. This reaction is original by the fact that a wide range of Grignard reagents can be used, in particularly mild conditions. This reaction has been applied to the synthesis of different α,α-disubstituted α-aminoacids, by oxidation of the alcohol functionality and hydrolysis of the amide moiety. Especially, divinylglycine has been prepared in good yield. The successive addition of two different Grignard reagents was also carried out, after optimization of reaction conditions, to access unsymmetrical hydroxyamides, which are precursors of chiral quaternary aminoacids. Finally, the addition of the Grignard reagents on N-ethoxycarbonyl 3-cyano-iminocoumarines was studied. Despite the presence of several electrophilic centers, the reaction is highly chemoselective, and novel chromenes displaying substituent on position 4 were obtained. The antifungal and antibacterial properties of these compounds have been evaluated

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21

CHABERT, PHILIPPE. "Applications synthetiques d'ylures d'arsonium fonctionnalises a la chimie des eicosanoides." Université Louis Pasteur (Strasbourg) (1971-2008), 1989. http://www.theses.fr/1989STR13060.

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22

Perry, Guenevere Diane. "Enhancing the Expression of Enzymes Used to Degrade Hydrocarbons and Cyanohydrins in Rhodococcus sp. DAP 96253 by Using Inducers such as Cobalt, Urea, and Propylene Gas; Also Enhances the Ability of the Bacteria to Delay the Ripening of Several Fruit Species." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/biology_diss/102.

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ABSTRACT Recent studies have shown that R. rhodochrous DAP 96253 has the ability to delay the ripening of many climacteric fruit, by potentially degrading volatile compounds released by plant cells during the ripening process. Rhodococcus rhodochrous DAP 96253 cells were cultured on YEMEA medium supplemented with inducers, (16mM cobalt and 125mM urea), that over-expressed nitrile hydratase (NHase) and amidase (AMDase) enzymes. Cells were cultured on propylene/ ethylene as sole carbon source to induce alkene monooxygenase (AMO) like activity. Induced R. rhodochrous DAP 96253 cells displayed an 83% increase in final total dry weight compared to cells previously cultured on non-induced medium. Induced R. rhodochrous DAP 96253 cells displayed a 53-85% increase in NHase activity after exposure to propylene/ethylene, and cells displayed a 24-53% increase in NHase activity after exposure to fruit. Non-induced R. rhodochrous DAP 96253 cells displayed a 1-5% increase in NHase activity after propylene/ethylene, and cells displayed an 18-38% increase in NHase activity after exposure to fruit. Propylene/ethylene induced nitrilase activity in non-induced R. rhodochrous DAP 96253cells. Experimental results suggest that R. rhodochrous DAP 96253 may use NHase, amidase, nitrilase, and AMO like activity to delay ripening of climacteric fruit. Rhodococcus rhodochrous 96253 cells cultured on propylene/ethylene and cofactors (16mM cobalt and 125mM urea) displayed improved ability to delay ripening of fruit.

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23

Hamberg, Anders. "Enzyme selectivity as a tool in analytical chemistry." Licentiate thesis, Stockholm : [School of Biotechnology, Royal Institute of Technology (KTH)], 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4377.

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24

Simard, Daniel. "Développement d'une nouvelle méthodologie de synthèse de tétrazoles oxabicycliques." Thèse, 2005. http://hdl.handle.net/1866/16761.

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25

Kassim, Muhammad Arshad. "Hydroxynitrile lyase activity in non-commercialised plants." Thesis, 2016. http://hdl.handle.net/10539/19342.

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A dissertation submitted to the School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2015
Cyanogenesis is defined as the hydroxynitrile lyase catalysed release of a cyanide group in the form of hydrogen cyanide and the corresponding aldehyde or ketone. When a plant is attacked, the hydrogen cyanide released is a self-defence mechanism. A special characteristic of enzymatic reactions is that all enzymatic reactions are reversible - hydroxynitrile lyases can also be used for the synthesis of enantiomerically pure cyanohydrins which are of great importance in industry. In this study, the hydroxynitrile lyase activity of 102 plants from 41 families was investigated, first by screening for cyanogenic activity, followed by a hydroxynitrile lyase activity assay. Six plants were found to be cyanogenic and exhibited specific hydroxynitrile lyase activity: Adenia sp. (0.44 U/mg), Adenia firingalavensis (2.88 U/mg), Adenia fruticosa (1.99 U/mg), Adenia pechuelii (2.35 U/mg), Heywoodia lucens (1.76 U/mg) and Ximenia caffra (1.84 U/mg). This is the first report of hydroxynitrile lyase activity in these plants.

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26

Tasi, Meng-Jung, and 蔡孟蓉. "Synthesis of Camphor-based Chiral Schiff Base and Its Application in the Asymmetric Reduction of Prochiral Ketones and Formation of Cyanohydrins." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/76409990537838018337.

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碩士
中興大學
化學系所
94
This thesis reports the development of an effective and enantioselective, camphor-based aminoalcohol chiral ligand modifier for the asymmetric reactions of carbonyl compounds. The chirally modified reducing agent was formed by mixing the Schiff base, derived from (1R,2S,3R)-3-amino-boneol and salicylaldehyde, and LAH at room temperature, which was employed in the asymmetric reduction of ten different prochiral ketones at –40 ºC. Taguchi method was used to find the optimal experimental conditions and the ratio of LAH: Schiff base: prochoral ketones = 1: 1.1: 0.5 was found to achieve the best results. S-Alcohols were obtained as the major products in excellent yields (72 %~>99 %) with moderate enantiomeric excesses (20 %~78 %). However, the addition of ethanol as a secondary modifier did not improve the reaction yields and the facial selectivities. In another application, the Schiff base and Ti(i-OPr)4 were mixed as a chiral catalyst for the asymmetric trimethylsilylcyanation of aldehydes. The reaction afforded the chiral cyanohydrin in excellent yields (91 %~>99 %) and good enantioselectivities (60 %~81 %). Thus, we have developed a camphor-based chiral aminoalcohol whose corresponding Schiff base was used in the asymmetric reduction of prochiral ketones and the formation of cyanohydrins in excellent yields and good enantioselectivites.

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27

Waltz, Marie-Ève. "Additions nucléophiles sur des B[beta]-alkoxyaldéhydes a[alpha],a[alpha]-disubstitués formés par une réaction radicalaire de transfert de vinyle intramoléculaire." Thèse, 2008. http://hdl.handle.net/1866/7804.

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Dissertations / Theses on the topic 'Cyanohydrine'

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