1: oxalyl chloride / benzene; dimethylformamide / 1 h / Ambient temperature 2: aq. Na2CO3 / tetrahydrofuran / 1 h / Ambient temperature 3: 83 percent / pyridine / ethanol / Heating 4: FeSO4, aq. conc. NH3 / 0.25 h / Heating 5: TsOH / toluene; tetrahydrofuran / 48 h / Heating View Scheme

1: oxalyl chloride / benzene; dimethylformamide / 1 h / Ambient temperature 2: aq. Na2CO3 / tetrahydrofuran / 1 h / Ambient temperature 3: NaBH3CN / ethanol / 3 h 4: H2 / 10percent Pd/C / ethanol / 4 h 5: 2.) conc. NH4OH / 1.) EtOH, RT, 16 h, 2.) EtOH, RT, 30 min View Scheme

1: oxalyl chloride / benzene; dimethylformamide / 0.5 h 2: triethylamine, 4-(dimethylamino)pyridine / tetrahydrofuran / 2 h / Ambient temperature View Scheme