1: 71 percent / conc. aq. HCl, pyridine 2: K2CO3 / acetone / 9 h / Heating 3: KOH / aq. ethanol 4: oxalyl chloride / benzene 5: triethylamine / benzene / 50 °C View Scheme

1: 71 percent / conc. aq. HCl, pyridine 2: K2CO3 / acetone / 9 h / Heating 3: KOH / aq. ethanol 4: acetic anhydride, sodium acetate / benzene / 24 h / Heating 5: 5 h / 150 °C View Scheme

1: 71 percent / conc. aq. HCl, pyridine 2: K2CO3 / acetone / 9 h / Heating 3: KOH / aq. ethanol 4: oxalyl chloride / benzene 5: triethylamine / benzene / 50 °C View Scheme