 Toluene

Toluene is methylbenzene, ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}{\mathrm{H}}_3$. It combines an aromatic ring with a benzylic methyl group, which creates reaction sites with different electronic environments.

It is a common organic solvent. Oxidation and substitution can affect either the side chain or the ring depending on reagents and mechanism, so identifying the reacting position is central to describing a toluene transformation.