1.1: sodium tetrahydroborate; acetic acid / 1,4-dioxane / 3.5 h / 10 - 105 °C 2.1: hydrogenchloride / water / 30 °C 2.2: 1 h / 0 - 20 °C 2.3: 1 h 3.1: sodium hydroxide / ethanol; water / 0.5 h / 60 °C / Inert atmosphere 3.2: 12 h / 60 °C / Inert atmosphere 4.1: toluene / 24 h / 120 °C 5.1: hydrogenchloride / ethanol / 1.5 h / 80 °C / Reflux 5.2: pH 14 View Scheme

1: With tetra-N-butylammonium borohydride in dichloromethane 16 h; Inert atmosphereReflux; 2: With hydrogenchloride in water 0.333333 h; Reflux; 3: With sodium carbonate in water Cooling; Product distribution / selectivity;

1.1: sodium tetrahydroborate; acetic acid / 1,4-dioxane / 3.5 h / 10 - 105 °C 2.1: hydrogenchloride / water / 30 °C 2.2: 1 h / 0 - 20 °C 2.3: 1 h 3.1: sodium hydroxide / ethanol; water / 0.5 h / 60 °C / Inert atmosphere 3.2: 12 h / 60 °C / Inert atmosphere View Scheme

Multi-step reaction with 4 steps 1.1: sodium tetrahydroborate; acetic acid / 1,4-dioxane / 3.5 h / 10 - 105 °C2.1: hydrogenchloride / water / 30 °C2.2: 1 h / 0 - 20 °C2.3: 1 h3.1: sodium hydroxide / ethanol; water / 0.5 h / 60 °C / Inert atmosphere3.2: 12 h / 60 °C / Inert atmosphere4.1: toluene / 24 h / 120 °C