1: With sodium hydroxide; water 1.5 - 2 h; Heating / reflux; 2: With hydrogenchloride in water T=25 - 35°C; pH=2; 0.75 - 1 h;

1: K2CO3 / diethyl ether / 30 h / 150 °C 2: N-bromosuccinimide, 2,2'-azo-bis-(isobutyronitril) / CCl4 3: 97 percent / aq. N-benzyl-tri-n-butylammonium-chloride / CH2Cl2 / 43 h / 20 °C 4: aq. HCl / 1.5 h / 20 - 23 °C 5: aq. NaNO2, aq. HCl / 2 h / 35 °C View Scheme

1: N-bromosuccinimide, 2,2'-azo-bis-(isobutyronitril) / CCl4 2: 97 percent / aq. N-benzyl-tri-n-butylammonium-chloride / CH2Cl2 / 43 h / 20 °C 3: aq. HCl / 1.5 h / 20 - 23 °C 4: aq. NaNO2, aq. HCl / 2 h / 35 °C View Scheme

1: 97 percent / aq. N-benzyl-tri-n-butylammonium-chloride / CH2Cl2 / 43 h / 20 °C 2: aq. HCl / 1.5 h / 20 - 23 °C 3: aq. NaNO2, aq. HCl / 2 h / 35 °C View Scheme

1: With triethylamine in toluene T=25 - 35°C; 1 - 2 h; Heating / reflux; 2: With water in toluene T=80 - 85°C; 0.25 - 0.5 h;