1.1: sodium hydroxide / ethanol; water / 0.5 h / 38 - 45 °C / pH 10 - 13 / Industry scale 2.1: nitric acid; sulfuric acid / sulfolane / 2 h / -5 - 30 °C 3.1: hydrogen / Raney Ni / methanol / 24 h / 40 - 50 °C 4.1: water / ethanol / 36 h / 60 °C / Industry scale 5.1: toluene / 3 h / Industry scale; Reflux 6.1: methylamine / ethanol / 4 h / 65 °C / Industry scale 6.2: 58 - 60 °C / pH 2.7 / Industry scale 7.1: 1,1'-carbonyldiimidazole / N,N-dimethyl-formamide / 1 h / 0 - 20 °C / Industry scale 7.2: 2.5 h / 0 - 25 °C View Scheme
