1.1: potassium carbonate / tert-butyl alcohol / 1.17 h / |Reflux 1.2: 11 h / |Reflux 2.1: thionyl chloride / chloroform / 1 h / |Reflux 3.1: acetic acid; piperidine / toluene / |Heating 4.1: hydrogen / tetrahydrofuran / 12 h 5.1: zinc; acetic acid / 15 h / 25 - 30 °C View Scheme

1.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0.08 h 1.2: 15 h / 25 - 90 °C 2.1: thionyl chloride / chloroform / 1 h / |Reflux 3.1: acetic acid; piperidine / toluene / |Heating 4.1: hydrogen / tetrahydrofuran / 12 h 5.1: hydrogenchloride / water; ethanol View Scheme

1.1: potassium carbonate / tert-butyl alcohol / 1.17 h / |Reflux 1.2: 11 h / |Reflux 2.1: thionyl chloride / chloroform / 1 h / |Reflux 3.1: acetic acid; piperidine / toluene / |Heating 4.1: zinc; acetic acid / methanol / 15 h / 25 - 30 °C View Scheme

1.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0.08 h 1.2: 15 h / 25 - 90 °C 2.1: triethylamine / dichloromethane / 4 h / 0 - 5 °C 3.1: acetic acid; piperidine / toluene / 4 h / 120 - 130 °C 4.1: palladium 10 on activated carbon; hydrogen / water; methanol / 14 h / 3102.97 Torr View Scheme

1.1: potassium carbonate / tert-butyl alcohol / 1.17 h / |Reflux 1.2: 11 h / |Reflux 2.1: pyrrolidine / methanol / 2 h / 50 - 55 °C / |Large scale 3.1: sodium tetrahydroborate; dmgH2; CoCl2.6H2O / water; N,N-dimethyl-formamide / 4 h / 65 - 85 °C / |Large scale View Scheme