1: 19.7 g / oxalyl dichloride, DMF / CH2Cl2 / 5 h / 25 °C 2: 1.) BuLi / 1.) THF, hexane, -25 deg C, 30 min, 2.) THF, hexane, -70 deg C, 1.5 h 3: 30.6 g / acetic anhydride / 120 °C 4: ethanol / 2 h / Ambient temperature 5: 20 percent / NaH / dioxane / 1.5 h / 45 °C View Scheme