1: Lawesson's reagent / tetrahydrofuran / 17 h / 20 °C / |Inert atmosphere 2: hydrogen / water; tetrahydrofuran / 2 h / 20 °C / |Inert atmosphere 3: sodium hydroxide / water / 16 h / 20 °C / pH 8 - 10 4: trifluoroacetic acid / dichloromethane / 17 h / 20 °C 5: hydrogen; palladium 10 on activated carbon / methanol / 1 h / 20 °C View Scheme

1: Lawesson's reagent / tetrahydrofuran / 17 h / 20 °C / |Inert atmosphere 2: hydrogen / water; tetrahydrofuran / 2 h / 20 °C / |Inert atmosphere 3: sodium hydroxide / water / 16 h / 20 °C / pH 8 - 10 4: trifluoroacetic acid / dichloromethane / 17 h / 20 °C View Scheme