1: hydrogenchloride / water / 3.5 h / 80 °C / |Sealed tube; |Inert atmosphere 2: thionyl chloride / 40 °C / |Inert atmosphere 3: sodium tetrahydroborate / methanol / 60 °C / |Inert atmosphere 4: triethylamine / methanol / 8 h / 30 °C / |Inert atmosphere View Scheme