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In Situ Evaluation of Lipase Performances Through Dynamic Asymmetric Cyanohydrin Resolution
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
(English)Manuscript (preprint) (Other academic)
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-24147OAI: oai:DiVA.org:kth-24147DiVA: diva2:344215
Note
QC 20100818Available from: 2010-08-18 Created: 2010-08-18 Last updated: 2011-05-26Bibliographically approved
In thesis
1. Dynamic Covalent Resolution: Applications in System Screening and Asymmetric Synthesis
Open this publication in new window or tab >>Dynamic Covalent Resolution: Applications in System Screening and Asymmetric Synthesis
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Combined thermodynamic/kinetic events amount to a kinetically controlled Dynamic Combinatorial Resolution (DCR) process, where the lability of themolecules/aggregates are used to generate dynamics, and the species experiencing the lowest activation energy is selected via kinetic process. Bothinter- and intramolecular processes can be performed using this concept,resulting in complete resolution and associated amplification of the selected species. When intermolecular processes are resolved using this method, an additional advantage is that only a catalytic amount of selector is required tocontrol the system.In this thesis, the Henry and Strecker reactions were developed as efficient C–C bond-forming routes to single and multi-level dynamic covalent systems.These methods efficiently provided a vast variety of substrates from smallnumbers of starting compounds. These dynamic systems, generated underthermodynamic control at mild conditions, were coupled in one-pot processes with kinetically controlled lipase-mediated transacylation. The enzym emediated resolution of the dynamic nitroaldol system led to enantiomericallypure β-nitroacetates in high yield. Furthermore, combination of multi-leveldynamic Strecker systems and lipase-mediated acylation resulted in theresolution of specific α-aminonitriles from the pool.In addition, the asymmetric synthesis of discrete β-nitroalkanol derivatives wassimply achieved, resulting in high yields and high enantiomeric purities through the direct one-pot procedure. Moreover, racemase type activity oflipase enzyme through N-substituted α-aminonitrile structure has been discovered. By use of control experiments together with molecular modeling,the mechanism of the racemization process has been established. Asymmetric synthesis of N-methyl α-aminonitriles was also performed through the dualfunction of lipase, resulting in high yield and good enantio selectivity.

Place, publisher, year, edition, pages
Stockholm: KTH, 2009. 72 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2009:52
Keyword
dynamic covalent/kinetic/combinatorial resolution, Self-screening, Transesterification, Amidation, Enzyme catalysis, Nitroaldol reaction, Secondary alcohols, Strecker reaction, Aminonitriles, Racemase, Enzyme catalytic promiscuity
National Category
Chemical Sciences Organic Chemistry Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-11200 (URN)978-91-7415-442-9 (ISBN)
Public defence
2009-10-15, F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20100818

Available from: 2009-10-05 Created: 2009-10-02 Last updated: 2012-09-03Bibliographically approved
2. Dynamic Systems: Evaluation, Screening and Synthetic Application
Open this publication in new window or tab >>Dynamic Systems: Evaluation, Screening and Synthetic Application
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The research work reported in the thesis deals with the development of dynamic covalent systems and their applications in evaluation and screening of protein-ligands and enzyme inhibitors, as well as in synthetic methodologies. The thesis is divided into four parts as described below.

In part one, synthetic methodologies to access 3-functionalized phthalides and 3-thioisoindolinones using the concept of cascade reactions are demonstrated. Efficient syntheses of the target products are designed and performed in one-pot process under mild reaction conditions.

 In part two, phosphine-catalyzed disulfide metathesis for the generation of dynamic carbohydrate system in aqueous solution is demonstrated. In the presence of biological target (Concanavalin A), the optimal dynamic ligand is successfully identified in situ by the 1H STD-NMR spectroscopy.

In part three, lipase-catalyzed resolutions of dynamic reversible systems using reversible cyanohydrin and hemithioacetal reactions in one-pot processes are demonstrated. The dynamic systems are generated under thermodynamic control in organic solution and subsequently resolved by lipase-mediated resolution under kinetic control. The resolution processes resulted in the lipase-selected substrates with high structural and stereochemical specificities.

In the last part, dynamic fragment-based strategy is presented using β-galactosidase as a model target enzyme. Based on our previous study, the best dynamic inhibitor of β-galactosidase was identified using 1H STD-NMR technique from dynamic hemithioacetal systems. The structure of the dynamic inhibitor is tailored by fragment linking and optimization processes. The designed inhibitor structures are then synthesized and tested for inhibition activities against β-galactosidase. 

 

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. 69 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2011:33
Keyword
constitutional dynamic chemistry; dynamic combinatorial chemistry/ resolution; dynamic fragment-based approach; dynamic kinetic resolution; dynamic reversible systems; 1H STD-NMR; multicomponent reaction; tandem reaction
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-34100 (URN)978-91-7415-986-8 (ISBN)
Public defence
2011-06-07, F3, KTH, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Funder
EU, European Research Council, MRTN-CT-2006-035614
Note
QC 20110526Available from: 2011-05-26 Created: 2011-05-25 Last updated: 2011-05-26Bibliographically approved

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