1: tetrabutylammomium bromide; sodium hydroxide / dichloromethane / 4 h / 40 °C 2: methanol; sodium methylate / 3 h / 20 °C 3: zinc(II) chloride / 12 h / 20 °C 4: pyridine / 10 h / 20 °C 5: acetic acid / 3 h / 80 °C 6: boron trifluoride diethyl etherate / dichloromethane / 20 h / 20 °C / Inert atmosphere; Molecular sieve 7: methanol; sodium methylate / 3 h / 20 °C View Scheme

1: methanol; sodium methylate / 3 h / 20 °C 2: zinc(II) chloride / 12 h / 20 °C 3: pyridine / 10 h / 20 °C 4: acetic acid / 3 h / 80 °C 5: boron trifluoride diethyl etherate / dichloromethane / 20 h / 20 °C / Inert atmosphere; Molecular sieve 6: methanol; sodium methylate / 3 h / 20 °C View Scheme

1: zinc(II) chloride / 12 h / 20 °C 2: pyridine / 10 h / 20 °C 3: acetic acid / 3 h / 80 °C 4: boron trifluoride diethyl etherate / dichloromethane / 20 h / 20 °C / Inert atmosphere; Molecular sieve 5: methanol; sodium methylate / 3 h / 20 °C View Scheme

1: tetrabutylammomium bromide; sodium hydroxide / dichloromethane / 4 h / 40 °C 2: methanol; sodium methylate / 3 h / 20 °C 3: zinc(II) chloride / 12 h / 20 °C 4: pyridine / 10 h / 20 °C 5: acetic acid / 3 h / 80 °C 6: boron trifluoride diethyl etherate / dichloromethane / 20 h / 20 °C / Inert atmosphere; Molecular sieve 7: methanol; sodium methylate / 3 h / 20 °C View Scheme