oxalyl dichloride; N,N-dimethyl-formamide in dichloromethane T=0 - 20°C; 3 h; Inert atmosphereCooling with ice;

1: NaH2PO4; H2O2; NaClO2 / acetonitrile; H2O / 20 °C 2: oxalyl chloride; DMF / CH2Cl2 / 1 h / 20 °C View Scheme

1.1: water; isopropanol acetate / 1.08 h / 2 - 35 °C / Inert atmosphere; Industry scale 2.1: potassium carbonate / copper(l) chloride / N,N-dimethyl-formamide; water / 30 °C 2.2: 105 °C / Inert atmosphere 2.3: pH 4 3.1: potassium carbonate / N,N-dimethyl-formamide; water / 30 °C 3.2: 1.08 h / 32 - 40 °C 4.1: dimethyl sulfoxide; isopropanol acetate / 17.5 h / 83 - 84 °C View Scheme

1: in tetrahydrofuran; hexane; acetonitrile T=0 - 20°C; 0.5 h; 2: With hydrogen bromide in tetrahydrofuran; hexane; water; acetonitrile T=0 - 20°C; 1 h;

in isopropanol acetate; water T=2 - 35°C; 1.08333 h; Inert atmosphereIndustry scale;

caesium carbonate in tetrahydrofuran

1.1: water; isopropanol acetate / 1.08 h / 2 - 35 °C / Inert atmosphere; Industry scale 2.1: potassium carbonate / copper(l) chloride / N,N-dimethyl-formamide; water / 30 °C 2.2: 105 °C / Inert atmosphere 2.3: pH 4 3.1: potassium carbonate / N,N-dimethyl-formamide; water / 30 °C 3.2: 1.08 h / 32 - 40 °C View Scheme

1.1: water; isopropanol acetate / 1.08 h / 2 - 35 °C / Inert atmosphere; Industry scale 2.1: potassium carbonate / copper(l) chloride / N,N-dimethyl-formamide; water / 30 °C 2.2: 105 °C / Inert atmosphere 2.3: pH 4 View Scheme

1: With diazomethyl-trimethyl-silane in tetrahydrofuran; diethyl ether; acetonitrile T=0 - 20°C; 2 h; 2: With water; silver(I) acetate in tetrahydrofuran; 1,4-dioxane; diethyl ether; acetonitrile T=100°C; 2 h;

triethylamine T=0 - 20°C; Product distribution / selectivity;