1: H2SO4 2: 82 percent / aq. NaBH4 / methanol / 2 h / Heating 3: 80 percent / pyridine / 3 h / Ambient temperature 4: 1.) NaH / 1.) DMF, 2.) DMF, 90 deg C, 2 h View Scheme

1: H2SO4 2: 82 percent / aq. NaBH4 / methanol / 2 h / Heating View Scheme

1: KOH / dimethylsulfoxide / 17 °C 2: 82.5 percent / HCl 3: 69 percent / NaBH4 / methanol / 1 h / Heating 4: 170 deg C View Scheme

in dichloromethane 1 h;

1.1: sodium hydrogencarbonate / 1-methyl-pyrrolidin-2-one / 80 °C / |Large scale 1.2: 65 °C / |Large scale 1.3: 12 h / 75 °C / |Large scale 2.1: pyridine / dichloromethane / 1 h / -5 °C / |Inert atmosphere; |Reflux; |Large scale 2.2: 1 h / -5 °C / |Inert atmosphere; |Large scale 3.1: 1-methyl-pyrrolidin-2-one; dichloromethane / 20 °C / |Inert atmosphere; |Reflux; |Large scale 3.2: 0 °C / |Inert atmosphere; |Large scale View Scheme

1.1: sodium hydrogencarbonate / 1-methyl-pyrrolidin-2-one / 80 °C / |Large scale 1.2: 65 °C / |Large scale 1.3: 12 h / 75 °C / |Large scale 2.1: pyridine / dichloromethane / 1 h / -5 °C / |Inert atmosphere; |Reflux; |Large scale 2.2: 1 h / -5 °C / |Inert atmosphere; |Large scale 3.1: 1-methyl-pyrrolidin-2-one; dichloromethane / 20 °C / |Inert atmosphere; |Reflux; |Large scale 3.2: 0 °C / |Inert atmosphere; |Large scale 4.1: methanol / 20 - 60 °C / |Large scale View Scheme

1: H2SO4 2: 82 percent / aq. NaBH4 / methanol / 2 h / Heating 3: 80 percent / pyridine / 3 h / Ambient temperature 4: 1.) NaH / 1.) DMF, 2.) DMF, 90 deg C, 2 h View Scheme

1: sulfuric acid / 15 h / 20 °C 2: 4-(N,N-dimethlyamino)pyridine / dichloromethane / 16 h / |Reflux; |Inert atmosphere 3: zinc / methanol; acetic acid / 1.08 h / 20 °C 4: potassium carbonate / N,N-dimethyl-formamide / 2.5 h / 35 °C View Scheme

1: sulfuric acid / 15 h / 20 °C 2: 4-(N,N-dimethlyamino)pyridine / dichloromethane / 16 h / |Reflux; |Inert atmosphere 3: zinc / methanol; acetic acid / 1.08 h / 20 °C 4: potassium carbonate / N,N-dimethyl-formamide / 2.5 h / 35 °C 5: sodium hydroxide / methanol; water / 0.75 h / |Reflux View Scheme