1: potassium hydrogen persulfate; sodium hydrogencarbonate / water; acetone / 0.5 h / 20 °C 2: boron trifluoride diethyl etherate / dichloromethane / 2 h / 0 °C / Inert atmosphere 3: lithium hydroxide hydrate / ethanol; water / 4 h / Reflux 4: hydrogenchloride / methanol; water / 4 h / Reflux View Scheme