scholarly journals Chemoenzymatic enantioselective synthesis of baclofen

1994 ◽  
Vol 72 (11) ◽  
pp. 2312-2317 ◽  
Author(s):  
Robert Chênevert ◽  
Michel Desjardins
Keyword(s):  
Enzymatic Hydrolysis ◽  
Acetic Anhydride ◽  
Aqueous Medium ◽  
Organic Medium ◽  
Enantioselective Synthesis ◽  
Enantioselective Syntheses ◽  
Hydrolysis Of

We report two different chemoenzymatic enantioselective syntheses of baclofen based on the distinction between enantiotopic ester groups in compounds bearing a prochiral centre. In the first approach, the key step is the highly stereoselective enzymatic hydrolysis of dimethyl 3-(4-chlorophenyl)glutarate by chymotrypsin in an aqueous medium. In the second approach, the key step is the enzyme-catalyzed esterification of 2-(4-chloropheny 1)-1,3-propanediol by acetic anhydride in the presence of a lipase in an organic medium.

Preparation of N-Acetylchitooligosaccharides by Enzymatic Hydrolysis of Chitosans

2010 ◽  
Vol 160-162 ◽  
pp. 1358-1361
Author(s):  
Hong Zhu ◽  
Zhi Hui Qiu ◽  
Qiong Hou
Keyword(s):  
Enzymatic Hydrolysis ◽  
Aspergillus Niger ◽  
Acetic Anhydride ◽  
Production Process ◽  
Chemical Reactions ◽  
Enzyme Preparations ◽  
High Yields ◽  
Hydrolysis Of

An economical production process of higher N-acetylchitooligosaccharides [(GlcNAc)n, n=5~7 ] was developed with enzymatic and chemical reactions in this study. (GlcNAc)n were prepared selectively and efficiently by hydrolysis of chitosans with cheap enzyme preparations including cellulase TV, cellulosin A.C and hemicellulase, followed by N-acetylation with acetic anhydride. Higher (GlcNAc)n could be obtained in high yields by using cellulosin A.C and hemicellulase, which are originated from Aspergillus niger.

Regioselective enzymatic hydrolysis of hexa-O-acetyl-lactal in a green non-aqueous medium

RSC Advances ◽  
2013 ◽  
Vol 3 (20) ◽  
pp. 7355 ◽  
Author(s):  
Teodora Bavaro ◽  
Pamela Torres-Salas ◽  
Daniela Ubiali ◽  
Marco Terreni
Keyword(s):  
Enzymatic Hydrolysis ◽  
Aqueous Medium ◽  
Hydrolysis Of

Microwave-assisted enzymatic hydrolysis of starch

2009 ◽  
Author(s):  
Marcin Lukasiewicz ◽  
Anna Osowiec ◽  
Magdalena Marciniak
Keyword(s):  
Enzymatic Hydrolysis ◽  
Microwave Assisted ◽  
Hydrolysis Of

Analyses of enzymatic hydrolysis of bagasse cane of sugar for obtention of ethanol employing a cocktail of natives commercials enzymes.  

2018 ◽  
Author(s):  
Ángel Batallas ◽  
Erenio González ◽  
Carmen Salvador ◽  
Jonathan Villavicencio ◽  
Humberto González Gavilánez ◽  
...  
Keyword(s):  
Enzymatic Hydrolysis ◽  
Hydrolysis Of

Enantioselective Syntheses of Flavonoid Diels-Alder Natural Products: A Review

2018 ◽  
Vol 15 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Shah Bakhtiar Nasir ◽  
Noorsaadah Abd Rahman ◽  
Chin Fei Chee
Keyword(s):  
Natural Products ◽  
Organic Synthesis ◽  
Lewis Acid ◽  
Alder Reaction ◽  
Diels Alder ◽  
Enantioselective Synthesis ◽  
Chiral Ligand ◽  
Asymmetric Syntheses ◽  
Diels Alder Reaction ◽  
Enantioselective Syntheses

Background: The Diels-Alder reaction has been widely utilised in the syntheses of biologically important natural products over the years and continues to greatly impact modern synthetic methodology. Recent discovery of chiral organocatalysts, auxiliaries and ligands in organic synthesis has paved the way for their application in Diels-Alder chemistry with the goal to improve efficiency as well as stereochemistry. Objective: The review focuses on asymmetric syntheses of flavonoid Diels-Alder natural products that utilize chiral ligand-Lewis acid complexes through various illustrative examples. Conclusion: It is clear from the review that a significant amount of research has been done investigating various types of catalysts and chiral ligand-Lewis acid complexes for the enantioselective synthesis of flavonoid Diels-Alder natural products. The results have demonstrated improved yield and enantioselectivity. Much emphasis has been placed on the synthesis but important mechanistic work aimed at understanding the enantioselectivity has also been discussed.

Immobilized Nanoparticles-Mediated Enzymatic Hydrolysis of Cellulose for Clean Sugar Production: A Novel Approach

2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai
Keyword(s):  
Catalytic Activity ◽  
Enzymatic Hydrolysis ◽  
Immobilized Enzyme ◽  
Free Enzyme ◽  
Magnetic Nanomaterials ◽  
Sugar Production ◽  
Cellulase Enzyme ◽  
Enzymatic Hydrolysis Of Cellulose ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.

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