1.1: sodium hydroxide / ethanol; water / 0.5 h / 60 °C / Inert atmosphere 1.2: 12 h / 60 °C / Inert atmosphere 2.1: toluene / 24 h / 120 °C 3.1: hydrogenchloride / ethanol / 1.5 h / 80 °C / Reflux 3.2: pH 14 View Scheme

1.1: sodium hydroxide; water / ethanol / 17 h / 80 °C 1.2: pH 2 2.1: N-ethyl-N,N-diisopropylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; benzotriazol-1-ol / N,N-dimethyl-formamide / 12 h / 20 °C 3.1: sodium tetrahydroborate; acetic acid / 1,4-dioxane / 3.5 h / 10 - 105 °C 4.1: hydrogenchloride / water / 30 °C 4.2: 1 h / 0 - 20 °C 4.3: 1 h 5.1: sodium hydroxide / ethanol; water / 0.5 h / 60 °C / Inert atmosphere 5.2: 12 h / 60 °C / Inert atmosphere 6.1: toluene / 24 h / 120 °C 7.1: hydrogenchloride / ethanol / 1.5 h / 80 °C / Reflux 7.2: pH 14 View Scheme

1.1: hydrogenchloride / water / 20 - 55 °C / Industry scale 1.2: 2.5 h / 5 - 45 °C / pH 12.4 / Industry scale 2.1: potassium hydroxide / diethylene glycol dimethyl ether / 42 h / 120 °C View Scheme

1.1: hydrogenchloride / water / 20 - 55 °C / Industry scale 1.2: 2.5 h / 5 - 45 °C / pH 12.4 / Industry scale 2.1: potassium hydroxide / diethylene glycol dimethyl ether / 42 h / 120 °C View Scheme

1: potassium phosphate / isobutyramide / 22 h / 100 °C 2: hydrogenchloride / isopropyl alcohol / 0.25 h View Scheme