1: 69 percent / PPA / 1 h / 85 - 90 °C 2: AlCl3 / CH2Cl2 / 1.5 h / 27 - 29 °C 3: 77.5 percent / AlCl3, EtSH / CH2Cl2 / 0.5 h / Ambient temperature View Scheme

1: 80.4 percent / KOH / ethanol; H2O; ethyl acetate / Ambient temperature 2: 69 percent / PPA / 1 h / 85 - 90 °C 3: AlCl3 / CH2Cl2 / 1.5 h / 27 - 29 °C 4: 77.5 percent / AlCl3, EtSH / CH2Cl2 / 0.5 h / Ambient temperature View Scheme

1.1: tetra(n-butyl)ammonium hydrogensulfate; potassium carbonate / ethyl acetate; water / 13 - 35 °C / Reflux 2.1: formic acid; sulfuric acid / acetic acid 3.1: thionyl chloride / N,N-dimethyl-formamide / toluene / 5 h / 65 - 70 °C 4.1: iron(III) sulfate pentahydrate; iron / toluene / 99 - 114 °C 4.2: 62 - 66 °C / Inert atmosphere 5.1: sodium hydroxide / tetrabutylammomium bromide / toluene; water / 6 h / Reflux 5.2: 20 °C 6.1: sodium hydroxide; tetrabutylammomium bromide / dichloromethane; water / 16 h / 20 °C 6.2: 2 - 51 °C 7.1: boron trichloride / dichloromethane / 52.25 h / 2 - 20 °C 7.2: 1.08 h / 12 °C / Reflux View Scheme

1.1: formic acid; sulfuric acid / acetic acid 2.1: thionyl chloride / N,N-dimethyl-formamide / toluene / 5 h / 65 - 70 °C 3.1: iron(III) sulfate pentahydrate; iron / toluene / 99 - 114 °C 3.2: 62 - 66 °C / Inert atmosphere 4.1: sodium hydroxide / tetrabutylammomium bromide / toluene; water / 6 h / Reflux 4.2: 20 °C 5.1: sodium hydroxide; tetrabutylammomium bromide / dichloromethane; water / 16 h / 20 °C 5.2: 2 - 51 °C 6.1: boron trichloride / dichloromethane / 52.25 h / 2 - 20 °C 6.2: 1.08 h / 12 °C / Reflux View Scheme

1.1: sodium hydroxide / tetrabutylammomium bromide / toluene; water / 6 h / Reflux 1.2: 20 °C 2.1: sodium hydroxide; tetrabutylammomium bromide / dichloromethane; water / 16 h / 20 °C 2.2: 2 - 51 °C 3.1: boron trichloride / dichloromethane / 52.25 h / 2 - 20 °C 3.2: 1.08 h / 12 °C / Reflux View Scheme

1.1: thionyl chloride / N,N-dimethyl-formamide / toluene / 5 h / 65 - 70 °C 2.1: iron(III) sulfate pentahydrate; iron / toluene / 99 - 114 °C 2.2: 62 - 66 °C / Inert atmosphere 3.1: sodium hydroxide / tetrabutylammomium bromide / toluene; water / 6 h / Reflux 3.2: 20 °C 4.1: sodium hydroxide; tetrabutylammomium bromide / dichloromethane; water / 16 h / 20 °C 4.2: 2 - 51 °C 5.1: boron trichloride / dichloromethane / 52.25 h / 2 - 20 °C 5.2: 1.08 h / 12 °C / Reflux View Scheme

boron trichloride in 1,2-dichloro-ethane T=0 - 35°C; 24 h;

1.1: sodium hydroxide; tetrabutylammomium bromide / dichloromethane; water / 16 h / 20 °C 1.2: 2 - 51 °C 2.1: boron trichloride / dichloromethane / 52.25 h / 2 - 20 °C 2.2: 1.08 h / 12 °C / Reflux View Scheme

1.1: sodium hydroxide; tetrabutylammomium bromide / dichloromethane; water / 16 h / 20 °C 1.2: 2 - 51 °C 2.1: boron trichloride / dichloromethane / 52.25 h / 2 - 20 °C 2.2: 1.08 h / 12 °C / Reflux View Scheme

1.1: bromine / methanol / 2.5 h / 10 °C 1.2: 4 h / 0 - 20 °C 2.1: polyphosphoric acid / 2 h / 65 - 90 °C 3.1: thionyl chloride / N,N-dimethyl-formamide; toluene / 2 h / 80 °C 3.2: 3 h / 20 °C View Scheme