titanium tetrachloride in dichloromethane T=-30°C; Methylation; 0.5 h;

trifluoroacetic acid Dehydration; Cyclization; 3 h; Heating;

selenium T=290°C;

1: 35 percent / AlCl3 / 5 h / 20 °C 2: 84 percent / polyphosphoric acid / 1.5 h / 90 - 95 °C 3: 85 percent / TiCl4 / CH2Cl2 / 0.5 h / -30 °C View Scheme

1: 84 percent / polyphosphoric acid / 1.5 h / 90 - 95 °C 2: 85 percent / TiCl4 / CH2Cl2 / 0.5 h / -30 °C View Scheme

1: 1.) AlCl3, 2.) K2CO3 / 1.) nitrobenzene a) 3 h, ice-bath temperature raising to 30 deg C, b) 3 h, 30 - 40 deg C, 2.) acetone, 12 h, reflux 2: 76 percent / anhydrous AlCl3 / benzene / 1.) 8 h, 65 deg C, 2.) overnight, room temperature 3: 79 percent / HCl, activated zinc dust / diethyl ether / 1.) during addition, 5 deg C, 2.) 3 h, 0 deg C 4: 1.) Mg / 1.) ether, 2.) a) room temperature, b) 1 h, reflux 5: 80 percent / toluene-p-sulphonic acid / benzene / 6 h / Heating View Scheme

1: 1.) Mg / 1.) ether, 2.) a) room temperature, b) 1 h, reflux 2: 80 percent / toluene-p-sulphonic acid / benzene / 6 h / Heating View Scheme

1: 79 percent / HCl, activated zinc dust / diethyl ether / 1.) during addition, 5 deg C, 2.) 3 h, 0 deg C 2: 1.) Mg / 1.) ether, 2.) a) room temperature, b) 1 h, reflux 3: 80 percent / toluene-p-sulphonic acid / benzene / 6 h / Heating View Scheme

1: 76 percent / anhydrous AlCl3 / benzene / 1.) 8 h, 65 deg C, 2.) overnight, room temperature 2: 79 percent / HCl, activated zinc dust / diethyl ether / 1.) during addition, 5 deg C, 2.) 3 h, 0 deg C 3: 1.) Mg / 1.) ether, 2.) a) room temperature, b) 1 h, reflux 4: 80 percent / toluene-p-sulphonic acid / benzene / 6 h / Heating View Scheme

hydrogenchloride; zinc(II) chloride in water T=80 - 90°C; 6 h;