1: HOBT, DCC / various solvent(s) / 1.5 h / 48 - 50 °C 2: 80 percent / DBU / acetonitrile / 1 h View Scheme

1,8-diazabicyclo[5.4.0]undec-7-ene; (4S)-3,3-diethyl-4-{4-[(4-methylpiperazinyl)-carbonyl]phenoxy}azetidin-2-one in various solvent(s)

1: dicyclohexyl-carbodiimide / ethyl acetate / 50 °C / |Reflux 2: potassium carbonate; tetra(n-butyl)ammonium hydrogensulfate / isopropanol acetate; water / 2.2 h / 45 °C / |Large scale 3: isopropanol acetate / 2.5 h / 70 °C / |Resolution of racemate; |Large scale 4: lithium tert-butylate / toluene; hexane / -10 °C / |Large scale View Scheme

1.1: tetrahydrofuran / 3 h / 10 - 30 °C / |Large scale 1.2: 1 h / 50 °C / |Large scale 2.1: acetic acid; palladium 10 on activated carbon; hydrogen / methanol; water / 20 - 25 °C / 760.05 Torr / |Large scale 2.2: 10 - 25 °C / |Large scale 3.1: pyridine / toluene / 100 - 110 °C / |Large scale 3.2: 106 - 110 °C / |Large scale 4.1: lithium tert-butylate / toluene; hexane / -10 °C / |Large scale View Scheme

1: potassium carbonate; tetra(n-butyl)ammonium hydrogensulfate / isopropanol acetate; water / 2.2 h / 45 °C / |Large scale 2: isopropanol acetate / 2.5 h / 70 °C / |Resolution of racemate; |Large scale 3: lithium tert-butylate / toluene; hexane / -10 °C / |Large scale View Scheme

1.1: hydrogen / ethanol / 6.5 h / 25 - 70 °C / 3878.71 - 7757.43 Torr / |Large scale 2.1: acetic acid; palladium 10 on activated carbon; hydrogen / toluene; water; ethanol / 8 h / 20 - 25 °C / 7757.43 Torr / |Large scale 2.2: 20 °C / |Large scale 3.1: pyridine / toluene / 100 - 110 °C / |Large scale 3.2: 106 - 110 °C / |Large scale 4.1: lithium tert-butylate / toluene; hexane / -10 °C / |Large scale View Scheme

1: isopropanol acetate / 2.5 h / 70 °C / |Resolution of racemate; |Large scale 2: lithium tert-butylate / toluene; hexane / -10 °C / |Large scale View Scheme

sodium chloride in hydrogenchloride T=60 - 80°C; pH=0.95 - 8.42; Kinetics; Further Variations:pH-valuesTemperaturesSolventsconc. of methanol, ionic strength;