bromine in diethyl ether T=10 - 20°C;

bromine; potassium carbonate in dichloromethane T=20°C; 1 h;

1: thionyl chloride / tetrachloromethane / 3 h / Reflux 2: boron trifluoride / acetonitrile / 8 h / Reflux 3: bromine; potassium carbonate / dichloromethane / 1 h / 20 °C View Scheme

1: boron trifluoride / acetonitrile / 8 h / Reflux 2: bromine; potassium carbonate / dichloromethane / 1 h / 20 °C View Scheme

1: palladium 10 on activated carbon; hydrogen / ethyl acetate / 15 h / 20 °C / 760.05 Torr 2: thionyl chloride / tetrachloromethane / 3 h / Reflux 3: boron trifluoride / acetonitrile / 8 h / Reflux 4: bromine; potassium carbonate / dichloromethane / 1 h / 20 °C View Scheme

1: potassium acetate / 4 h / 160 - 180 °C 2: palladium 10 on activated carbon; hydrogen / ethyl acetate / 15 h / 20 °C / 760.05 Torr 3: thionyl chloride / tetrachloromethane / 3 h / Reflux 4: boron trifluoride / acetonitrile / 8 h / Reflux 5: bromine; potassium carbonate / dichloromethane / 1 h / 20 °C View Scheme

sodium acetate; acetic acid 24 h; Reflux;

3,4-Diamino[3,4-b]pyridine; acetic acid 3 h; Reflux;