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Regioselective alcoholysis of silychristin acetates catalyzed by lipases.

Vavříková E, Gavezzotti P, Purchartová K, Fuksová K, Biedermann D, Kuzma M, Riva S, Křen V - Int J Mol Sci (2015)

Bottom Line: Acetylation at primary alcoholic group (C-22) of silychristin was accomplished by lipase PS (Pseudomonas cepacia) immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/ n-butanol.Both of these reactions occurred without diastereomeric discrimination of silychristin A and B.Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. vavrikova@biomed.cas.cz.

ABSTRACT
A panel of lipases was screened for the selective acetylation and alcoholysis of silychristin and silychristin peracetate, respectively. Acetylation at primary alcoholic group (C-22) of silychristin was accomplished by lipase PS (Pseudomonas cepacia) immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/ n-butanol. Both of these reactions occurred without diastereomeric discrimination of silychristin A and B. Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.

No MeSH data available.


Time course study of lipase PS-catalyzed acetylation of natural silychristin composed of silychristin A () and silychristin B () yielding 22-O-acetyl derivatives, A () and B (); () ratio of peak areas of 22-O-acetyl silychristin A:22-O-acetyl silychristin B (secondary axis y; please note that this axis has a different scale).
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ijms-16-11983-f002: Time course study of lipase PS-catalyzed acetylation of natural silychristin composed of silychristin A () and silychristin B () yielding 22-O-acetyl derivatives, A () and B (); () ratio of peak areas of 22-O-acetyl silychristin A:22-O-acetyl silychristin B (secondary axis y; please note that this axis has a different scale).

Mentions: A panel of lipases were screened (Table 1), and various solvents (acetone, tert-amyl alcohol, toluene, dioxane, THF) were tested for the acetylation of natural silychristin (1a/1b = 9:1; we use hereunder the term “silychristin (1)” for this mixture if not otherwise stated). The best result was achieved with lipase PS (Pseudomonas cepacia) immobilized on diatomite in acetone in the presence of vinyl acetate as the acyl donor (Scheme 1). This enzymatic acetylation proceeded to give a quantitative yield of 22-O-acetyl silychristin without any traces of side products and allowed a simple reaction mixture workup. However, virtually no diastereomeric discrimination of silychristin A and B was observed during time course study (Figure 2).


Regioselective alcoholysis of silychristin acetates catalyzed by lipases.

Vavříková E, Gavezzotti P, Purchartová K, Fuksová K, Biedermann D, Kuzma M, Riva S, Křen V - Int J Mol Sci (2015)

Time course study of lipase PS-catalyzed acetylation of natural silychristin composed of silychristin A () and silychristin B () yielding 22-O-acetyl derivatives, A () and B (); () ratio of peak areas of 22-O-acetyl silychristin A:22-O-acetyl silychristin B (secondary axis y; please note that this axis has a different scale).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490424&req=5

ijms-16-11983-f002: Time course study of lipase PS-catalyzed acetylation of natural silychristin composed of silychristin A () and silychristin B () yielding 22-O-acetyl derivatives, A () and B (); () ratio of peak areas of 22-O-acetyl silychristin A:22-O-acetyl silychristin B (secondary axis y; please note that this axis has a different scale).
Mentions: A panel of lipases were screened (Table 1), and various solvents (acetone, tert-amyl alcohol, toluene, dioxane, THF) were tested for the acetylation of natural silychristin (1a/1b = 9:1; we use hereunder the term “silychristin (1)” for this mixture if not otherwise stated). The best result was achieved with lipase PS (Pseudomonas cepacia) immobilized on diatomite in acetone in the presence of vinyl acetate as the acyl donor (Scheme 1). This enzymatic acetylation proceeded to give a quantitative yield of 22-O-acetyl silychristin without any traces of side products and allowed a simple reaction mixture workup. However, virtually no diastereomeric discrimination of silychristin A and B was observed during time course study (Figure 2).

Bottom Line: Acetylation at primary alcoholic group (C-22) of silychristin was accomplished by lipase PS (Pseudomonas cepacia) immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/ n-butanol.Both of these reactions occurred without diastereomeric discrimination of silychristin A and B.Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. vavrikova@biomed.cas.cz.

ABSTRACT
A panel of lipases was screened for the selective acetylation and alcoholysis of silychristin and silychristin peracetate, respectively. Acetylation at primary alcoholic group (C-22) of silychristin was accomplished by lipase PS (Pseudomonas cepacia) immobilized on diatomite using vinyl acetate as an acetyl donor, whereas selective deacetylation of 22-O-acetyl silychristin was accomplished by Novozym 435 in methyl tert-butyl ether/ n-butanol. Both of these reactions occurred without diastereomeric discrimination of silychristin A and B. Both of these enzymes were found to be capable to regioselective deacetylation of hexaacetyl silychristin to afford penta-, tetra- and tri-acetyl derivatives, which could be obtained as pure synthons for further selective modifications of the parent molecule.

No MeSH data available.