1.1: hydrogenchloride; water / N,N-dimethyl-formamide / 2 h / 16 °C / Inert atmosphere 2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 0.5 h / -60 °C 2.2: 2 h / -60 - 20 °C 3.1: pyridinium p-toluenesulfonate / toluene / 1.6 h / 60 °C / Inert atmosphere 4.1: palladium 10 on activated carbon; hydrogen / ethyl acetate / 24 h / 20 °C / Inert atmosphere; Darkness 5.1: lithium hydroxide hydrate / tetrahydrofuran; water / 16.25 h / 20 °C / Inert atmosphere 5.2: 1 h / Inert atmosphere View Scheme

Multi-step reaction with 4 steps 1.1: hydrogenchloride; water / N,N-dimethyl-formamide / 2 h / 16 °C / Inert atmosphere2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 0.5 h / -60 °C2.2: 2 h / -60 - 20 °C3.1: pyridinium p-toluenesulfonate / toluene / 1.6 h / 60 °C / Inert atmosphere4.1: palladium 10 on activated carbon; hydrogen / ethyl acetate / 24 h / 20 °C / Inert atmosphere; Darkness  

Multi-step reaction with 4 steps 1.1: sodium tetrahydroborate / ethanol / 16 h / 0 °C / Inert atmosphere2.1: tributylphosphine; 1,1'-azodicarbonyl-dipiperidine / tetrahydrofuran / 1 h / Inert atmosphere3.1: 1H-imidazole / tetrahydrofuran / 1 h / 20 °C / Inert atmosphere4.1: potassium hexamethylsilazane / N,N-dimethyl-formamide / 0.25 h / 0 °C / Inert atmosphere4.2: 1.67 h / Inert atmosphere4.3: 1 h / Inert atmosphere  

Multi-step reaction with 3 steps 1.1: tributylphosphine; 1,1'-azodicarbonyl-dipiperidine / tetrahydrofuran / 1 h / Inert atmosphere2.1: 1H-imidazole / tetrahydrofuran / 1 h / 20 °C / Inert atmosphere3.1: potassium hexamethylsilazane / N,N-dimethyl-formamide / 0.25 h / 0 °C / Inert atmosphere3.2: 1.67 h / Inert atmosphere3.3: 1 h / Inert atmosphere  

Multi-step reaction with 2 steps 1.1: 1H-imidazole / tetrahydrofuran / 1 h / 20 °C / Inert atmosphere2.1: potassium hexamethylsilazane / N,N-dimethyl-formamide / 0.25 h / 0 °C / Inert atmosphere2.2: 1.67 h / Inert atmosphere2.3: 1 h / Inert atmosphere  

Multi-step reaction with 2 steps 1.1: sulfuric acid / 2.5 h / 20 - 25 °C / Inert atmosphere1.2: 10 °C / Cooling with ice; Inert atmosphere2.1: potassium hexamethylsilazane / N,N-dimethyl-formamide / 0.25 h / 0 °C / Inert atmosphere2.2: 1.67 h / Inert atmosphere2.3: 1 h / Inert atmosphere