Substituent effects on reactive oxygen species (ROS) generation by hydroquinones.

In order to understand the structural aspects of stabilization of hydroquinones and their ability to generate reactive oxygen species (ROS), we designed and synthesized a series of 6-aryl-2,3-dihydro-1,4-benzoquinones. These compounds equilibrate with the corresponding 6-aryl-1,4-dihydroxybenzenes in an organic medium; a linear free energy relationship analysis gave ρ = +2.37, suggesting that this equilibrium was sensitive to electronic effects. The propensity of the compound to enolize appears to determine ROS-generating capability, thus offering scope for tunable ROS generation.