1: ethyl acetate / 4 h / -50 °C / Inert atmosphere 2: water / 1 h / -50 - 20 °C / Inert atmosphere 3: water / 0.5 h / 20 °C / Inert atmosphere View Scheme

1: hydrogenchloride / ethyl acetate / 1.5 h / -50 °C / Inert atmosphere 2: ethyl acetate / 4 h / -50 °C / Inert atmosphere 3: water / 1 h / -50 - 20 °C / Inert atmosphere 4: water / 0.5 h / 20 °C / Inert atmosphere View Scheme

1.1: diisopropylamine / tetrahydrofuran / -30 °C / Inert atmosphere 1.2: 0.5 h / Inert atmosphere 2.1: hydrogenchloride / ethyl acetate / 1.5 h / -50 °C / Inert atmosphere 3.1: ethyl acetate / 4 h / -50 °C / Inert atmosphere 4.1: water / 1 h / -50 - 20 °C / Inert atmosphere 5.1: water / 0.5 h / 20 °C / Inert atmosphere View Scheme

1.1: sodium hydroxide / methanol; water / 2.5 h / -30 °C / Inert atmosphere 1.2: 1 h / 0 °C / pH 3.5 / Inert atmosphere 2.1: diisopropylamine / tetrahydrofuran / -30 °C / Inert atmosphere 2.2: 0.5 h / Inert atmosphere 3.1: hydrogenchloride / ethyl acetate / 1.5 h / -50 °C / Inert atmosphere 4.1: ethyl acetate / 4 h / -50 °C / Inert atmosphere 5.1: water / 1 h / -50 - 20 °C / Inert atmosphere 6.1: water / 0.5 h / 20 °C / Inert atmosphere View Scheme

in water T=20°C; 0.5 h; Inert atmosphere;

1.1: sodium hydrogencarbonate / water / Inert atmosphere 1.2: 20 °C / Inert atmosphere 2.1: formic acid; titanium tetrachloride / dichloromethane / 1.25 h / 0 - 20 °C / Inert atmosphere View Scheme