1.1: trifluoroacetic acid; sodium tetrahydroborate / dichloromethane / 6 h / 15 - 20 °C / |Large scale 2.1: triethylamine; potassium iodide; potassium carbonate / N,N-dimethyl-formamide / 16 h / 85 °C / |Large scale 3.1: sodium hydroxide / methanol / 4 h / |Reflux; |Large scale 4.1: 1,1'-carbonyldiimidazole / methanol / 1 h / 20 °C / |Reflux; |Large scale 4.2: 0.5 h / |Large scale View Scheme