1: 94 percent / KOH, H2O2 / H2O; methanol / 0.5 h / Ambient temperature 2: 95 percent / fuming HNO3, conc. H2SO4 / 0.5 h / 0 °C 3: 64 percent / conc. HCl / 24 h / 150 °C 4: H2O; acetic acid / 2 h / 50 °C View Scheme

1: 57 percent / PPA / 0.25 h / 145 °C 2: 94 percent / KOH, H2O2 / H2O; methanol / 0.5 h / Ambient temperature 3: 95 percent / fuming HNO3, conc. H2SO4 / 0.5 h / 0 °C 4: 64 percent / conc. HCl / 24 h / 150 °C 5: H2O; acetic acid / 2 h / 50 °C View Scheme

1: 95 percent / fuming HNO3, conc. H2SO4 / 0.5 h / 0 °C 2: 64 percent / conc. HCl / 24 h / 150 °C 3: H2O; acetic acid / 2 h / 50 °C View Scheme

1: 4.3 percent Chromat. / 1) NaNO2, 3 N HCl, 2) KI / 1) H2O, 0 degC, 1.5 h, 2) warm to room temp., 4 h 2: 95 percent / fuming HNO3, conc. H2SO4 / 0.5 h / 0 °C 3: 64 percent / conc. HCl / 24 h / 150 °C 4: H2O; acetic acid / 2 h / 50 °C View Scheme

1: 64 percent / conc. HCl / 24 h / 150 °C 2: H2O; acetic acid / 2 h / 50 °C View Scheme

1: 86 percent / conc. HCl / methanol / 0.08 h / Heating 2: 64 percent / conc. HCl / 24 h / 150 °C 3: H2O; acetic acid / 2 h / 50 °C View Scheme

in water; acetic acid T=50°C; 2 h; Yield given;