Abstract

In this work, the novel Spiro cycles with high potential antibacterial activity were synthesized via a one-pot and environmentally friendly electrochemical approach, without toxic reagents and solvents. In the first, electrochemical oxidation of caffeic acid (1) in the presence of barbituric acids (3a-c) as nucleophiles have been studied using cyclic voltammetry and controlled-potential coulometry. The obtained electrochemical results demonstrate that an electrooxidative/Michael-type sequential reaction occurs between the barbituric acids and the caffeic acid o-quinone produced by electrooxidation of caffeic acid leading to the corresponding novel Spiro cycles (8a-c). The mechanism of the electrochemical reaction was suggested as an ECEC (Electron transfer, Chemical reaction, Electron transfer, Chemical reaction) pathway using cyclic voltammetry, controlled-potential coulometry and spectroscopic data. The antibacterial activities of the synthesized compounds were investigated and compared with caffeic acid and barbituric acids.