1: With acetic anhydride; acetic acid 5.5 h; RefluxInert atmosphere; 2: With hydrogenchloride; water 3 h; Reflux;

hydrogenchloride; water T=100°C;

1: With acetic anhydride; acetic acid T=90°C; 2: With hydrogenchloride in water T=100°C;

sodium hydrogencarbonate in water 2 h; Yield given;

thionyl chloride T=20°C;

thionyl chloride T=0°C; Inert atmosphere;

thionyl chloride

sodium hydrogencarbonate in 1,4-dioxane; water T=0 - 20°C;

1: thionyl chloride / 6 h / Heating 2: triethylamine / CH2Cl2 / 6 h / Heating 3: 1.) oxalyl chloride, dimethyl sulfoxide, 2.) triethylamine / 1.) CH2Cl2, -78 deg C, 30 min, 2.) CH2Cl2, from -78 deg C to RT 4: ethanol; H2O / 24 h / 55 - 60 °C 5: 64 percent / 6 N aq. HCl / 24 h / 130 °C 6: 76 percent / H2 / 20percent Pd(OH)2-C / aq. acetic acid / 10 h / 2280 Torr / Ambient temperature View Scheme

1: thionyl chloride / 6 h / Heating 2: triethylamine / CH2Cl2 / 6 h / Heating 3: 1.) oxalyl chloride, dimethyl sulfoxide, 2.) triethylamine / 1.) CH2Cl2, -78 deg C, 30 min, 2.) CH2Cl2, from -78 deg C to RT 4: ethanol; H2O / 24 h / 55 - 60 °C 5: 64 percent / 6 N aq. HCl / 24 h / 130 °C View Scheme