1: FeSO4, aq. NH4OH / ethanol / Heating 2: 2.) p-TsOH*H2O / 1.) toluene, reflux, 0.5 h, 2.) toluene, reflux, 5 h View Scheme

toluene-4-sulfonic acid 1.) toluene, reflux, 0.5 h, 2.) toluene, reflux, 5 h; Yield given. Multistep reaction;