1: bromine / 1,4-dioxane / 60 h / 10 - 20 °C / |Inert atmosphere 2: sodium hydroxide / methanol / 3 h / |Reflux 3: sulfuric acid / 25 h / 20 - 25 °C View Scheme

1: sodium hydroxide / methanol / 3 h / |Reflux 2: sulfuric acid / 25 h / 20 - 25 °C View Scheme

1: Dowex 50W-X8 resin / toluene / 30 h / |Dean-Stark; |Heating 2: bromine / 1,4-dioxane / 60 h / 10 - 20 °C / |Inert atmosphere 3: sodium hydroxide / methanol / 3 h / |Reflux 4: sulfuric acid / 25 h / 20 - 25 °C View Scheme

1: With hydrogenchloride in methanol; water 40 h; Inert atmosphereIrradiation; 2: in water 1.5 h; RefluxInert atmosphere; 3: With sodium hydroxide in water 4.5 h; RefluxInert atmosphere;

1.1: hydrogenchloride / methanol; water / 40 h / |Inert atmosphere; |Irradiation 1.2: 1.5 h / |Reflux; |Inert atmosphere 1.3: 4.5 h / |Reflux; |Inert atmosphere 2.1: Dowex 50W-X8 resin / methanol / 24 h / |Reflux 3.1: sodium hydroxide / methanol; tetrahydrofuran / 14 h / 20 °C View Scheme

1.1: hydrogenchloride / methanol; water / 40 h / |Inert atmosphere; |Irradiation 1.2: 1.5 h / |Reflux; |Inert atmosphere 1.3: 4.5 h / |Reflux; |Inert atmosphere 2.1: Dowex 50W-X8 resin / methanol / 24 h / |Reflux View Scheme

pentacarbonyliron in xylene 12 h; Heating;