1: 2.) 20percent methanolic H2SO4 / 1.) methanol, 0 deg C, 10 min, 2.) 0 deg C, 10 min 2: 90 percent / H2SO4 / 1,2-dichloro-ethane / 4 h / Heating 3: 1.) oxalyl chloride, DMSO / 1.) CH2Cl2, -82 deg C, 3 min, 2.) CH2Cl2, from -82 deg C to -67 deg C, 30 min 4: Et3N / CH2Cl2 / 0.03 h / Heating View Scheme