Syntheses of Carbamate Derivatives of Quercetin by Reaction with Amino Acid Ester Isocyanates

Synthesis of amino acid carbamate derivatives of quercetin from partly protected quercetin and amino acid esters utilizing triphosgene as an auxiliary reagent was studied. A series of quercetin derivatives were obtained regioselectively by reaction with amino acid ester isocyanates under mild conditions and in high yields.