The production of enantiopure compounds can be achieved by using dehydrogenases as biocatalysts catalyzing reduction reactions of prochiral compounds such as ketones, aldehydes and nitriles. These dehydrogenases are cofactor dependent enzyme where cofactor is Nicotinamide dinucleotite having some restrictions that limits usage of dehydrogenases in organic synthesis including instability of cofactor in water and high cost. Therefore suitable regeneration method is needed and developed which are enzymatic and electrochemical. We will use an electrochemical approach for the regeneration of reduced co-factors which has been shown in principal with mediators like pentamethylcyclopentadienyl rhodium bipyridine complexes or ferrocenes. This project is European Union project, whose name is Development of Electrochemical Reactors Using Dehydrogenases for Enantiopure Synthon Preparations.
All active compounds / mediator, cofactor and enzyme, will be immobilized on the electrode surface of the constructed reactor surface. Therefore only educts and
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products will exist in the reactor medium. A gas diffusion electrode will be employed as a counter electrode / which delivers clear protons to the system. Mediator will carry electrons to the cofactor for cofactor regeneration. Then enzyme will use the cofactor and convert substrates to the product in high stereoselectivity. Our part in this project is the synthesis of mediator and suitable linkers for enzyme, cofactor and mediator immobilization. In the first part of the study, Linkers which contain thiol group and disulfide linkage were synthesized because working electrode made of by gold nano particles and immobilization carried out by the help of these groups on gold nano surface. In the second part of the study, mediators were synthesized which are pentamethylcyclopentadienyl rhodium bipyridine complexes and ferrocene derivatives. Synthesized mediators were reacted with linkers by using Click Chemistry and by imine formation in order to convert mediator to the thiol functionalized form.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12610930/index.pdf |
| Date | 01 September 2009 |
| Creators | Akbasoglu, Naime |
| Contributors | Demir, Ayhan Sitki |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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