| Autor: |
Zbynek Prokop, Jian-He Xu, Jiang Pan, Chun-Xiu Li, Hui-Lei Yu, Jiri Damborsky, Jia Zeng, Veronika Stepankova, Jerzy Luczak, Gao-Wei Zheng, Piotr Kiełbasiński, Marian Mikołajczyk, Aitao Li, Radka Chaloupková, Jixun Zhan, Khomaini Hasan |
| Rok vydání: |
2012 |
| Předmět: |
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| Zdroj: |
Practical Methods for Biocatalysis and Biotransformations 2 |
| Popis: |
In the last 50 years the number of known natural organo-halogen compounds has grown from a dozen to more than 4000 today. The most studied group of halogenase biocatalysts are haloperoxidases, which are able to accelerate a wide range of halogenation reactions following the mode of action represented in Scheme 11.1. More recently new halogenases have been identified such as 2-oxoglutarate irondependent halogenase, nucleophilic halogenases that can introduce fluorine and FADH2 dependant halogenases. The FADH2 cofactor enzymes can halogenate substrates with excellent regioselectivity. A good example of this reaction is the synthesis of isolated 7chlorotriptophan by Walsh et al. a target synthesis that would involve many steps using traditional organic synthesis methods (Scheme 11.2). Hence this group of enzymes offers the chemical industry significant improvements in synthetic methodologies as low regio-selectivities are usually obtained in traditional halogenation reagents and these reagents are limited to reaction at specific activated sites. Halogenases are now known that regioselectively halogenate all four positions of the indole benzene ring which is not possible with chemical reagents. By replacing chloride salts by bromide salts in the reaction media bromination is possible in many cases. Dehalogenases have been known to efficiently dehalogenate activated halogen compounds and are applied on the large scale for the synthesis of (S)-chloropropionic acid as |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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