1: perphthalic acid / diethyl ether / 0 °C 2: 1.) cc.H2SO4; 2.) 5percent KOH / 1.) 0 deg. C, H2O, 2 h; 2.) 100 deg C, 1 h View Scheme

potassium hydroxide; sulfuric acid 1.) 0 deg. C, H2O, 2 h; 2.) 100 deg C, 1 h; Multistep reaction;