1-Hydroxy-4-unsubstituted benzenoid → 1,4-Dihydroxybenzenoid derivative<br><br>Comments:<br>This rule is excluded from acting on catechols, polynuclear aromatics and mono-substituted phenols with R= -CH<sub>2</sub>CH<sub>2</sub>CH<sub>3</sub> or -OCH<sub>2</sub>CH<sub>4</sub>.
