1: trifluoroacetic acid / 48 h / 50 °C 2: sodium hydride; p-toluenesulfonyl chloride / tetrahydrofuran / 4 h / Ambient temperature 3: lithium aluminium tetrahydride / diethyl ether / 1 h / 0 °C 4: pyridinium p-toluenesulfonate / dichloromethane / 8 h / Ambient temperature 5: hydrogen / palladium on carbon / ethanol 6: pyridine / 48 h / Ambient temperature 7: N,N,N',N',N'',N''-hexamethylphosphoric triamide; sodium hydride / 1.) DMF, RT, 24 h, 2.) DMF, 50 deg C, 7 d 8: hydrogenchloride / methanol / 12 h / Ambient temperature View Scheme

1: tetrahydrofuran / 12 h / Ambient temperature 2: sodium hydride / 1.) THF, reflux, 0.5 h, 2.) THF, reflux, 2 h 3: trifluoroacetic acid / 48 h / 50 °C 4: sodium hydride; p-toluenesulfonyl chloride / tetrahydrofuran / 4 h / Ambient temperature 5: lithium aluminium tetrahydride / diethyl ether / 1 h / 0 °C 6: pyridinium p-toluenesulfonate / dichloromethane / 8 h / Ambient temperature 7: hydrogen / palladium on carbon / ethanol 8: pyridine / 48 h / Ambient temperature 9: N,N,N',N',N'',N''-hexamethylphosphoric triamide; sodium hydride / 1.) DMF, RT, 24 h, 2.) DMF, 50 deg C, 7 d 10: hydrogenchloride / methanol / 12 h / Ambient temperature View Scheme

1: pyridine / 48 h / Ambient temperature 2: N,N,N',N',N'',N''-hexamethylphosphoric triamide; sodium hydride / 1.) DMF, RT, 24 h, 2.) DMF, 50 deg C, 7 d 3: hydrogenchloride / methanol / 12 h / Ambient temperature View Scheme