title: Regioselective alcoholysis of silychristin acetates catalyzed by lipases.
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.
authors.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.
authors.forename: Eva
authors.initials: E
authors.lastname: Vavříková
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare, Consiglio Nazionale delle Ricerche, Via Mario Bianco 9, I 20131 Milano, Italy. paolo.gavezzotti@gmail.com.
authors.forename: Paolo
authors.initials: P
authors.lastname: Gavezzotti
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. katerina.purchartova@gmail.com.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Purchartová
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. karol.fuksova@gmail.com.
authors.forename: Kateřina
authors.initials: K
authors.lastname: Fuksová
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. david.biedermann@gmail.com.
authors.forename: David
authors.initials: D
authors.lastname: Biedermann
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. kuzma@biomed.cas.cz.
authors.forename: Marek
authors.initials: M
authors.lastname: Kuzma
authors.affiliation: Istituto di Chimica del Riconoscimento Molecolare, Consiglio Nazionale delle Ricerche, Via Mario Bianco 9, I 20131 Milano, Italy. sergio.riva@icrm.cnr.it.
authors.forename: Sergio
authors.initials: S
authors.lastname: Riva
authors.affiliation: Laboratory of Biotransformation, Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic. kren@biomed.cas.cz.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Křen
mesh_terms: D000085:Acetates / Q000138:chemical synthesis*; D000107:Acetylation; D001426:Bacterial Proteins / Q000378:metabolism; D055162:Biocatalysis; D016956:Burkholderia cepacia / Q000201:enzymology*; D004800:Enzymes, Immobilized / Q000378:metabolism; D008049:Lipase / Q000378:metabolism*; D015394:Molecular Structure; D012042:Registries; D012838:Silymarin / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D012838:Silymarin; D008049:Lipase; C015504:silychristin
keywords: acetylation; alcoholysis; lipase; silychristin; silymarin