1: 89 percent / pyridine / CH2Cl2 / 1 h / Ambient temperature 2: 86 percent / NaOH / ethanol; H2O / 2 h / Heating 3: oxalyl chloride, DMF / CH2Cl2 / 1 h / 0 deg C, 30 min, r.t. 30 min 4: 84 percent / AlCl3 / CH2Cl2 / 0.5 h / Ambient temperature View Scheme