1: With pyridine; dicyclohexyl-carbodiimide; trifluoroacetic acid in dimethyl sulfoxide; benzene T=20°C; Moffatt oxidation; 18 h; 2: With oxalic acid in methanol; dimethyl sulfoxide; benzene Moffatt oxidation; 0.5 h;

1.1: sodium hydride / dimethylformamide / 1 h / 0 - 5 °C 1.2: 75 percent / dimethylformamide / 20 h 2.1: 72 percent / acetic acid; water / 5 h / 80 °C 3.1: pyridine; trifluoroacetic acid; DCC / dimethylsulfoxide; benzene / 18 h / 20 °C 3.2: 76 percent / oxalic acid / dimethylsulfoxide; benzene; methanol / 0.5 h View Scheme

1.1: 72 percent / acetic acid; water / 5 h / 80 °C 2.1: pyridine; trifluoroacetic acid; DCC / dimethylsulfoxide; benzene / 18 h / 20 °C 2.2: 76 percent / oxalic acid / dimethylsulfoxide; benzene; methanol / 0.5 h View Scheme