1.1: toluene-4-sulfonic acid / dichloromethane / 25 - 30 °C 2.1: water; sodium hydroxide / tetrahydrofuran; methanol / 25 - 30 °C 3.1: hydrogenchloride / water; ethyl acetate / 25 - 30 °C 4.1: N-ethyl-N,N-diisopropylamine / dichloromethane / 25 - 30 °C 4.2: 1 h / 0 - 5 °C 5.1: sodium methylate / methanol; N,N-dimethyl-formamide / 0 - 5 °C 6.1: ethyl acetate / 25 - 30 °C 7.1: sodium methylate / methanol; N,N-dimethyl-formamide / 26 h / 25 - 45 °C 8.1: sulfuric acid; water / 2.5 h / 0 - 10 °C / Inert atmosphere View Scheme

1.1: hydrogenchloride / water; ethyl acetate / 25 - 30 °C 2.1: N-ethyl-N,N-diisopropylamine / dichloromethane / 25 - 30 °C 2.2: 1 h / 0 - 5 °C 3.1: sodium methylate / methanol; N,N-dimethyl-formamide / 0 - 5 °C 4.1: ethyl acetate / 25 - 30 °C 5.1: sodium methylate / methanol; N,N-dimethyl-formamide / 26 h / 25 - 45 °C 6.1: sulfuric acid; water / 2.5 h / 0 - 10 °C / Inert atmosphere View Scheme

1.1: sodium methylate / methanol; N,N-dimethyl-formamide / 1 h / -15 °C 1.2: 10 h / -5 - 5 °C 2.1: water; sodium hydroxide / methanol / 3 h / 60 - 65 °C View Scheme