1: 85 percent / 1 h / Heating 2: 90 percent / sodium hydride / dimethylformamide / 0.67 h / 30 °C 3: 1.) 2.2 M n-butyllithium, 2.) bromine / 1.) THF, -40 deg C, 2 h 4: pyridine hydrochloride / 2 h / 180 °C 5: K2CO3 / dimethylformamide / 1.) 60 deg C, 2 h, 2.) from 60 deg C to RT, overnight 6: aq. NaOH / dimethylformamide / 1.5 h / 90 °C View Scheme