1.1: 1,1'-carbonyldiimidazole / ethyl acetate / 3 h / 0 - 30 °C 1.2: 20 - 25 °C 2.1: potassium carbonate / acetonitrile / 70 °C 2.2: 15 h / 0 - 25 °C 3.1: lithium hexamethyldisilazane / tetrahydrofuran / 1 h / -70 - -10 °C 4.1: sulfuric acid / acetonitrile / 3 h / 50 - 60 °C View Scheme

1.1: 1,1'-carbonyldiimidazole / ethyl acetate / 3 h / 0 - 30 °C 1.2: 20 - 25 °C 2.1: potassium carbonate / acetonitrile / 70 °C 2.2: 15 h / 0 - 25 °C 3.1: lithium hexamethyldisilazane / tetrahydrofuran / 1 h / -20 - -10 °C 4.1: hydrogenchloride; water / acetonitrile / 15 h / 40 °C 5.1: sodium hydroxide; water / ethanol / 16 h / 20 - 25 °C View Scheme