Peracetylation of polyphenols under rapid and mild reaction conditions

Structure modification is an important tool on studying properties of naturally occurring polyphenols. Regarding preparation of acetyl esters, the presence of hydroxyl groups stabilized by intramolecular hydrogen bond may pose as an obstacle for the peracetylation of such polyphenols1,2. In this work we present a facile protocol for the acetylation of selected polyphenols under mild reaction conditions, by using acetic anhydride, catalytic 4-dimethylaminopyridine (DMAP) and dimethylformamide (DMF) as solvent3. Reaction conditions were adjusted for optimal formation of peracetylated polyphenols while minimizing the formation of by-products. Butyric anhydride was employed as alternative acylating agent and showed similar results. Reaction yields varied from 78–97% and products were obtained in high purity, as determined by LCMS(ESI+), 1H NMR and 13C NMR.