1: With potassium hydroxide in water; isopropyl alcohol T=50°C; 2: With acetic acid in water; isopropyl alcohol

in ethanol; N,N-dimethyl-formamide

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

1.1: thionyl chloride / toluene; N,N-dimethyl-formamide / 3 h / 60 °C 2.1: magnesium chloride; triethylamine / toluene; tetrahydrofuran / 1 h / 0 - 50 °C / |Large scale 3.1: 0.5 h / 140 °C 3.2: 12 h / 140 °C 4.1: 1-methyl-pyrrolidin-2-one / acetonitrile / 1 h / |Large scale 5.1: 1-methyl-pyrrolidin-2-one; lithium chloride; 1,8-diazabicyclo[5.4.0]undec-7-ene / 3.67 h / 23 - 35 °C 6.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / 2 h / 23 °C 7.1: 1 h / 35 °C / |Large scale 8.1: 1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione / dichloromethane / 1.5 h / 5 °C 9.1: isopropyl alcohol; water / 50 °C View Scheme

1.1: magnesium chloride; triethylamine / toluene; tetrahydrofuran / 1 h / 0 - 50 °C / |Large scale 2.1: 0.5 h / 140 °C 2.2: 12 h / 140 °C 3.1: 1-methyl-pyrrolidin-2-one / acetonitrile / 1 h / |Large scale 4.1: 1-methyl-pyrrolidin-2-one; lithium chloride; 1,8-diazabicyclo[5.4.0]undec-7-ene / 3.67 h / 23 - 35 °C 5.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / 2 h / 23 °C 6.1: 1 h / 35 °C / |Large scale 7.1: 1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione / dichloromethane / 1.5 h / 5 °C 8.1: isopropyl alcohol; water / 50 °C View Scheme

1.1: 0.5 h / 140 °C 1.2: 12 h / 140 °C 2.1: 1-methyl-pyrrolidin-2-one / acetonitrile / 1 h / |Large scale 3.1: 1-methyl-pyrrolidin-2-one; lithium chloride; 1,8-diazabicyclo[5.4.0]undec-7-ene / 3.67 h / 23 - 35 °C 4.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / 2 h / 23 °C 5.1: 1 h / 35 °C / |Large scale 6.1: 1,3-Dichloro-5,5-dimethyl-2,4-imidazolidinedione / dichloromethane / 1.5 h / 5 °C 7.1: isopropyl alcohol; water / 50 °C View Scheme