1: 83.5 percent / 1 N HCl / trifluoroacetic acid / 55 °C 2: 42 percent / sodium dithionite / dimethylformamide / 0.25 h / 50 °C 3: dimethylformamide / 2 h / 100 - 120 °C View Scheme

1: 83.5 percent / 1 N HCl / trifluoroacetic acid / 55 °C 2: 42 percent / sodium dithionite / dimethylformamide / 0.25 h / 50 °C 3: dimethylformamide / 2 h / 100 - 120 °C 4: 33 percent / 1 N NaOH / H2O / 0.5 h / 80 °C 5: thionyl chloride / benzene / 2 h / Heating 6: 2.) HCl / 1.) ether, methylene chloride, RT, 1 h View Scheme