Detection of a Radical Cation of an NADH Analogue in Two‐Electron Reduction of a Protonated p‐Quinone Derivative by an NADH Analogue

An electron-transfer pathway is preferred to a direct hydride-transfer pathway in two-electron reduction of protonated 1-(p-tolylsulfinyl)-2,5-benzoquinone by the NADH analogue 10-methyl-9,10-dihydroacridine, as has been demonstrated for the first time by ESR detection of the resulting radical cation of the acridine derivative (see picture).