Green synthesis and antioxidant activity of novel series of benzofurans from euparin extracted of Petasites hybridus.

A novel class of benzofuran derivatives is prepared from the isocyanide-based MCR, euparin and aldehydes in the presence of ZnO-nanorods as a catalyst in excellent yields at room temperature under solvent-free conditions as a green reaction medium. Also, the antioxidant activities of some synthesised compounds such as 4a, 4b, 10a and 10b were evaluated by DPPH radical scavenging and ferric reduction activity potential (FRAP) assays. Compound 10b, was shown moderate radical scavenging activity and very good reducing activity compared to standards (BHT and TBHQ).