PPA T=100°C; 4 h;

With  water; acetic acid T=100°C; 10 h;   

Multi-step reaction with 2 steps 1: 32 percent / KOH (s) / dimethylsulfoxide / Ambient temperature2: 11 percent / 30percent aq. H2O2 / acetic acid / 1 h / 40 - 50 °C