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Published on: January 15, 2018
One-pot one-step deracemization of amines using ω-transaminases
Giyoung Shin1, Sam Mathew, Minsu Shon
1School of Biotechnology, Yeungnam University, Gyeongsan, Gyeongbuk, South Korea. hyungdon@ynu.ac.kr.
Chemical Communications (Cambridge, England)
|June 25, 2013
Summary
A novel one-pot, one-step deracemization method efficiently produces enantiomerically pure amines. This method utilizes two opposing enantioselective ω-transaminases (ω-TAs) for high-purity amine synthesis.
Area of Science:
- Organic Chemistry
- Biocatalysis
- Asymmetric Synthesis
Background:
- Chiral amines are crucial building blocks in pharmaceuticals and fine chemicals.
- Existing methods for producing enantiomerically pure amines can be complex and inefficient.
Purpose of the Study:
- To develop a streamlined, one-pot, one-step method for the deracemization of amines.
- To achieve high enantiomeric purity and good conversion rates in amine production.
Main Methods:
- Employed a novel deracemization strategy using two ω-transaminases (ω-TAs) with opposite enantioselectivity.
- Optimized reaction conditions for a one-pot, one-step process.
Main Results:
- Successfully produced various enantiomerically pure aromatic amines.
- Achieved high enantiomeric excess (>99%) for the (R)-enantiomers.
- Demonstrated good overall conversion rates for the targeted amines.
Conclusions:
- The developed one-pot, one-step deracemization method is highly effective for synthesizing enantiomerically pure amines.
- This approach offers a significant advancement in biocatalytic amine production, providing a more efficient and scalable alternative.
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Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
01:19Amines to Amides: Acylation of Amines
Various carboxylic acid derivatives (such as acid chlorides, esters, and anhydrides) can be used for the acylation of amines to yield amides. The reaction requires two equivalents of amines. The first amine molecule functions as a nucleophile and attacks the carbonyl carbon to produce a tetrahedral intermediate. This is followed by the loss of the leaving group and restoration of the C=O bond.
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary amide...
01:07Acid Halides to Amides: Aminolysis
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
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01:28Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
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