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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 the alcoholysis of silychristin peracetate (3, ♦) at 45 °C in MTBE/n-butanol catalyzed by lipase PS immobilized on diatomite. Products (3,5,15,19,22-penta-O-acetyl silychristin, 4, ), (3,15,19,22-tetra-O-acetyl silychristin, 5, ) and (3,15,22-tri-O-acetyl silychristin, 6, ).
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ijms-16-11983-f004: Time course study of the alcoholysis of silychristin peracetate (3, ♦) at 45 °C in MTBE/n-butanol catalyzed by lipase PS immobilized on diatomite. Products (3,5,15,19,22-penta-O-acetyl silychristin, 4, ), (3,15,19,22-tetra-O-acetyl silychristin, 5, ) and (3,15,22-tri-O-acetyl silychristin, 6, ).

Mentions: Based on the above screening, Novozym 435 and lipase PS immobilized on diatomite were used for preparatory-scale alcoholysis experiments. Product formation during the regioselective alcoholysis of 3 was monitored by HPLC (Figure 4 and Figure 5). The reactions catalyzed by Novozym 435 and by lipase PS immobilized on diatomite afforded different products (Scheme 2). All of the compounds were isolated and characterized by mass spectrometry and complex NMR investigation, allowing their unequivocal structural determination. Control experiments proved that no spontaneous alcoholysis of 3 occurred in the absence of the enzymes.


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 the alcoholysis of silychristin peracetate (3, ♦) at 45 °C in MTBE/n-butanol catalyzed by lipase PS immobilized on diatomite. Products (3,5,15,19,22-penta-O-acetyl silychristin, 4, ), (3,15,19,22-tetra-O-acetyl silychristin, 5, ) and (3,15,22-tri-O-acetyl silychristin, 6, ).
© Copyright Policy
Related In: Results  -  Collection

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

ijms-16-11983-f004: Time course study of the alcoholysis of silychristin peracetate (3, ♦) at 45 °C in MTBE/n-butanol catalyzed by lipase PS immobilized on diatomite. Products (3,5,15,19,22-penta-O-acetyl silychristin, 4, ), (3,15,19,22-tetra-O-acetyl silychristin, 5, ) and (3,15,22-tri-O-acetyl silychristin, 6, ).
Mentions: Based on the above screening, Novozym 435 and lipase PS immobilized on diatomite were used for preparatory-scale alcoholysis experiments. Product formation during the regioselective alcoholysis of 3 was monitored by HPLC (Figure 4 and Figure 5). The reactions catalyzed by Novozym 435 and by lipase PS immobilized on diatomite afforded different products (Scheme 2). All of the compounds were isolated and characterized by mass spectrometry and complex NMR investigation, allowing their unequivocal structural determination. Control experiments proved that no spontaneous alcoholysis of 3 occurred in the absence of the enzymes.

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.