1: 1) conc. HCl, NaNO2, 2) CuCl2/conc. HCl / 1) 10 deg C, 5 min 2) 5 deg C, 30 min, then RT, 1 h 2: 99 percent / HCl / ethanol / 1 h / Heating 3: 95 percent / polyphosphoric acid / 2.5 h / 120 °C 4: 65 percent / methanol 5: DDQ / dioxane View Scheme

Multi-step reaction with 2 steps 1: 1) conc. HCl, NaNO2, 2) CuCl2/conc. HCl / 1) 10 deg C, 5 min 2) 5 deg C, 30 min, then RT, 1 h2: 99 percent / HCl / ethanol / 1 h / Heating  

With  hydrogenchloride; copper dichloride; sodium nitrite  1) 10 deg C, 5 min 2) 5 deg C, 30 min, then RT, 1 h;  Yield given. Multistep reaction;   

Multi-step reaction with 2 steps 1: 98.5 percent / NaOH, H2O2 / 1) 40-60 deg C, 1 h 2) reflux, 4h2: 76 percent / NaOH, Br2 / H2O / 0.75 h / 70 °C  

Multi-step reaction with 3 steps 1: phosphoryl chloride / 5 h / 100 °C2: 98.5 percent / NaOH, H2O2 / 1) 40-60 deg C, 1 h 2) reflux, 4h3: 76 percent / NaOH, Br2 / H2O / 0.75 h / 70 °C