1: dichloromethane / Inert atmosphere 2: sodium hydride / tetrahydrofuran; mineral oil / Inert atmosphere; Heating 3: hydrogenchloride; water; acetic acid / Reflux 4: triethylamine / acetonitrile / Inert atmosphere; Reflux View Scheme

1: 94 percent / ethanol / 1 h / Ambient temperature 2: 84 percent / potassium carbonate / dimethylformamide / 2 h / 140 - 150 °C 3: 98 percent / conc. H2SO4 / H2O; acetic acid / 1.5 h / Heating View Scheme

1: dichloromethane / Inert atmosphere 2: sodium hydride / tetrahydrofuran; mineral oil / Inert atmosphere; Heating 3: hydrogenchloride; water; acetic acid / Reflux View Scheme

1: 1-methyl-pyrrolidin-2-one / acetonitrile / 1 h / |Large scale 2: 1-methyl-pyrrolidin-2-one; lithium chloride; 1,8-diazabicyclo[5.4.0]undec-7-ene / 3.67 h / 23 - 35 °C 3: 1,8-diazabicyclo[5.4.0]undec-7-ene / 2 h / 23 °C 4: 1 h / 35 °C / |Large scale 5: 1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione / dichloromethane / 1.5 h / 5 °C 6: isopropyl alcohol; water / 50 °C View Scheme

1: 94 percent / ethanol / 1 h / Ambient temperature 2: 84 percent / potassium carbonate / dimethylformamide / 2 h / 140 - 150 °C View Scheme