urea T=175°C; 1 h;

1: N,N-dimethyl-formamide / 5 h / 20 - 100 °C 2: sodium hydroxide; water / methanol / 4 h / Reflux 3: urea / 1 h / 175 °C View Scheme

1: sodium hydroxide; water / methanol / 4 h / Reflux 2: urea / 1 h / 175 °C View Scheme

1: triethylamine / dichloromethane / 2 h / 20 °C / Cooling with ice 2: N,N-dimethyl-formamide / 5 h / 20 - 100 °C 3: sodium hydroxide; water / methanol / 4 h / Reflux 4: urea / 1 h / 175 °C View Scheme