1: 95 percent / 2 M NaOH / tetrahydrofuran / 2 h / Heating 2: 73 percent / pyridine, TFA, DCC / benzene; dimethylsulfoxide / Ambient temperature 3: Na2CO3 / ethanol; H2O / 1 h / Heating 4: acetic acid / 0.5 h / 100 °C 5: 65 percent / HgO, HgCl2 / methanol; H2O / 2 h / Heating View Scheme