Synthesis of lipophilic antioxidants by a lipase-B-catalyzed addition of peracids to the double bond of 4?vinyl-2- methoxyphenol
Zago E. | Durand E. | Barouh N. | Lecomte J. | Villeneuve P. | Aouf C.
4-Vinyl guaiacol (2) was lipophilized through the electrophilic addition of peracids to its vinylic double bond. Those peracids were formed in situ, by the Candida antarctica lipase-B-assisted perhydrolysis of carboxylic acids ranging from C2 to C18, in hydrogen peroxide solution. The addition of peracids with 4–8 carbons in their alkyl chains led to the formation of two regioisomers, with the prevalence of hydroxyesters bearing a primary free hydroxyl (4c–4e). This prevalence became more pronounced when peracids with longer alkyl chains (C10–C18) were used. In this case, only isomers 4f–4h were formed. The antioxidant activity of the resulting hydroxyesters was assessed by means of the conjugated autoxidizable triene (CAT) assay, and it was found out that the 4-vinyl guaiacol antioxidant activity was significantly increased by grafting alkyl chains with 2–8 carbons. (Résumé d'auteur)
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