1.1: sodium hydroxide / water / 10 h / 20 - 25 °C 2.1: sodium hydroxide / water / 0.5 h / 0 - 5 °C 2.2: 14 h / 5 - 10 °C 2.3: 0 - 5 °C 3.1: chloroformic acid ethyl ester; 4-methyl-morpholine / dichloromethane / 0.25 h / -15 - -10 °C 3.2: 3 h / -15 - 25 °C View Scheme