Selective nitration versus oxidative dealkylation of hydroquinone ethers with nitrogen dioxide
Various alkyl-substituted p-dialkoxybenzenes (ArH) react readily with nitrogen dioxide (NO2) in dichloromethane solution via either nitration (ArNO2) or oxidative dealkylation to quinones (Q). Spectral transients indicate that these coupled processes from the dialkoxybenzene radical cation (ArH+·) formed as the common reactive intermediate from electron-transfer in the disproprtionated precursor [ArH, NO+] N03-. In fast subsequent steps. ArH+· undergoes homolytic coupling with NO2 (which leads to aromatic nitration) and nucleophilic attack of NO3- (which results in oxidative dealkylation). As such, the competition between nitration and oxidative dealkylation is effectively modulated by solvent polarity and added nitrate.
Rathore, R., E. Bosch, and J. K. Kochi. "Selective nitration versus oxidative dealkylation of hydroquinone ethers with nitrogen dioxide." Tetrahedron 50, no. 23 (1994): 6727-6758.