A novel and efficient synthesis of 3,4-dihydroxyphenylacetic ester and amide derivatives/conjugates and assessment of their antioxidant activity

Abstract

<p>Phenolic acids, a sub-class of polyphenols, are widely studied. By contrary, 3,4-dihydroxyphenylacetic acid is scarcely studied. For this purpose, a series of 3,4-dihydroxyphenylacetic acid ester and amide derivatives/conjugates were synthesised for the first time. A systematic study has been performed to quantitatively identify the functional groups present in these compounds using different techniques such as ¹H NMR, ¹³C NMR and ESI MS. The synthesised compounds were evaluated for their <i>in vitro</i> antioxidant activity by a DPPH radical-scavenging assay. Their physico-chemical profile is also studied using Molinspiration tool. Among all tested compounds, amidoester <b>36</b> showed the best scavenging activity possessing an EC₅₀ 17 μΜ and improved physico-chemical properties compared to the parent compound.</p