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Chemo‐enzymatic Synthesis of 6″‐ O ‐(3‐Arylprop‐2‐enoyl) Derivatives of the Flavonol Glucoside Isoquercitrin
Author(s) -
Danieli Bruno,
Bertario Andrea,
Carrea Giacomo,
Redigolo Barbara,
Secundo Francesco,
Riva Sergio
Publication year - 1993
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19930760823
Subject(s) - chemistry , knoevenagel condensation , moiety , hydrolysis , glucoside , regioselectivity , residue (chemistry) , catalysis , enzyme , organic chemistry , enzyme catalysis , enzymatic hydrolysis , benzaldehyde , stereochemistry , medicine , alternative medicine , pathology
A chemo‐enzymatic approach to some 6″‐ O ‐(3‐arylprop‐2‐enoyl) derivatives of the flavonol glucoside isoquercitrin ( 2a ) was explored to overcome the inability to directly introduce these acyl moieties by an enzyme‐catalyzed reaction of 2a with the corresponding activated esters. This new approach was based on the regioselective introduction of a methyl malonate residue at the CH 2 OH of the sugar moiety by catalysis with the protease subtilisin (→ 22a ). The mixed diester 22a was then subjected to chemoselective hydrolysis of the methoxycarbonyl function by another enzyme, biophine esterase (→ 23 ). Finally, the malonic monoester 23 was reacted in a Knoevenagel ‐type condensation with benzaldehyde, 4‐hydroxybenzaldehyde, or 4‐hydroxy‐3‐methoxybenzaldehyde to afford the target 6″‐ O ‐(3‐arylprop‐2‐enoyl) isoquercitrins 2b–d .