1: sodium hydride / tetrahydrofuran; mineral oil / |Inert atmosphere; |Reflux 2: sodium hydride / mineral oil; N,N-dimethyl-formamide / 0 °C 3: trifluoroacetic acid / dichloromethane; methanol / 20 °C 4: sodium hydride / mineral oil; N,N-dimethyl-formamide / 0 - 20 °C 5: 2,3-dicyano-5,6-dichloro-p-benzoquinone / dichloromethane; water / 3 h / 20 °C View Scheme