1: 0.5 h / 120 °C 2: sodium hydroxide / water / 2 h / 40 °C 3: thionyl chloride; triethylamine / dichloromethane / 1.25 h / 0 - 5 °C 4: N,N-dimethyl-formamide / 14 h / 80 °C 5: thionyl chloride / chloroform / 1 h / |Reflux 6: acetic acid; piperidine / toluene / |Heating 7: hydrogen / tetrahydrofuran / 12 h 8: zinc; acetic acid / 15 h / 25 - 30 °C View Scheme

1: 0.5 h / 120 °C 2: sodium hydroxide / water / 2 h / 40 °C 3: thionyl chloride; triethylamine / dichloromethane / 1.25 h / 0 - 5 °C 4: N,N-dimethyl-formamide / 14 h / 80 °C 5: pyrrolidine / methanol / 2 h / 50 - 55 °C / |Large scale 6: sodium tetrahydroborate; dmgH2; CoCl2.6H2O / water; N,N-dimethyl-formamide / 4 h / 65 - 85 °C / |Large scale 7: thionyl chloride / chloroform / 2 h / |Reflux 8: hydrogenchloride 9: zinc; propionic acid / ethanol / 12 h 10: hydrogenchloride / water; ethanol View Scheme

1: 0.5 h / 120 °C 2: sodium hydroxide / water / 2 h / 40 °C 3: thionyl chloride; triethylamine / dichloromethane / 1.25 h / 0 - 5 °C 4: N,N-dimethyl-formamide / 14 h / 80 °C 5: thionyl chloride / chloroform / 1 h / |Reflux 6: acetic acid; piperidine / toluene / |Heating 7: zinc; acetic acid / methanol / 15 h / 25 - 30 °C View Scheme

1: 0.5 h / 120 °C 2: sodium hydroxide / water / 2 h / 40 °C 3: thionyl chloride; triethylamine / dichloromethane / 1.25 h / 0 - 5 °C 4: N,N-dimethyl-formamide / 14 h / 80 °C 5: thionyl chloride / chloroform / 1 h / |Reflux 6: acetic acid; piperidine / toluene / |Heating 7: hydrogen / tetrahydrofuran / 12 h View Scheme

1: 0.5 h / 120 °C 2: sodium hydroxide / water / 2 h / 40 °C 3: thionyl chloride; triethylamine / dichloromethane / 1.25 h / 0 - 5 °C 4: N,N-dimethyl-formamide / 14 h / 80 °C 5: pyrrolidine / methanol / 2 h / 50 - 55 °C / |Large scale 6: sodium tetrahydroborate; dmgH2; CoCl2.6H2O / water; N,N-dimethyl-formamide / 4 h / 65 - 85 °C / |Large scale View Scheme