1: Dowex 50W / acetone; water / |Reflux 2: sodium methylate / tetrahydrofuran / -78 - 20 °C / |Inert atmosphere 3: sodium tetrahydroborate / water; tetrahydrofuran / 20 °C 4: calcium carbonate; methyl iodide / water; acetonitrile / 47 h / 20 °C 5: 5 palladium on charcoal; hydrogen / ethanol 6: tetrafluoroboric acid / acetonitrile / 18 h / 20 °C View Scheme