Synthesis of cinnamic acid-derived phenethyl carbamates and their radical scavenging ability toward DPPH free radicals

A simple and efficient synthetic detail of cinnamic acid carbamate derivatives and their antioxidant activities was studied. The antioxidant activity of the compounds was measured by standard free radical scavenging assay (DPPH test) as a primary tool. The activity results were analyzed to determine the quantitative structure-activity relationships. The cinnamic acid analogs were easily converted to their corresponding azides by treating them with diphenyl phosphoryl azide (DPPA). The resulting isocyanate produced from azide was reacted in situ with phenethyl alcohol to give the carbamate compounds. The antioxidant activity was measured by DPPH radical scavenging assay as a primary tool to investigate their antioxidant activity, which could analyzed for the study of structure-activity relationship. The results show that the DPPH radical scavenging activities of the compounds increase in concentration dependent manner.