boron tribromide in dichloromethane

potassium carbonate in dimethyl sulfoxide T=120°C; 6 h;

potassium carbonate in N,N-dimethyl-formamide T=110°C; 24 h; Sealed vessel;

trifluorormethanesulfonic acid

1: potassium carbonate / 1-methyl-pyrrolidin-2-one / 10 h / 120 °C 2: boron tribromide / dichloromethane / 0.5 h / -20 - -10 °C View Scheme

1.1: potassium carbonate / 1-methyl-pyrrolidin-2-one / 5 h / 115 - 120 °C 1.2: 20 °C / pH 3 - 4 / Acidic conditions 2.1: sulfuric acid / 1,4-dioxane; water / 5 h / 95 - 100 °C 3.1: acetic acid / methanol / 1 h / 20 °C 3.2: 25 - 45 °C 4.1: sodium hydroxide; water / methanol / 6 h / 20 °C View Scheme

hydrogenchloride; sodium hydroxide

potassium carbonate in ethyl acetate; N,N-dimethyl-formamide

1: potassium carbonate / acetonitrile / 66 h / 90 - 100 °C 2: triethylamine / dichloromethane / 1 h / 20 °C / Cooling with ice View Scheme

1.1: potassium carbonate / 1-methyl-pyrrolidin-2-one / 5 h / 115 - 120 °C 1.2: 20 °C / pH 3 - 4 / Acidic conditions 2.1: sulfuric acid / 1,4-dioxane; water / 5 h / 95 - 100 °C 3.1: acetic acid / methanol / 1 h / 20 °C 3.2: 25 - 45 °C 4.1: sodium hydroxide; water / methanol / 6 h / 20 °C 5.1: sodium hydroxide; dihydrogen peroxide / dimethyl sulfoxide / 6 h / 20 °C View Scheme