1: 73 percent / Benzyltriethylammonium Permanganate / CH2Cl2 / 5 h / 20 °C 2: 61 percent / Aluminium chloride / 1,2-dichloro-ethane / 1.5 h / Heating 3: 71 percent / aniline / pyridine / 2 h / 60 °C 4: 72 percent / Copper powder, quinoline / 1 h / Heating View Scheme