sodium hydroxide in 1,2-dioxacyclohexane; water T=0 - 20°C; 16 h;

sodium carbonate in tetrahydrofuran; water T=23°C; 20 h;

methanol; water

1: 39 g / potassium carbonate / dimethylformamide / 0 - 23 °C 2: 34.3 g / calcium chloride; sodium borohydride / ethanol / 0 - 20 °C 3: 27 g / ethyldiisopropylamine; methanesulfonic anhydride / 1,2-dichloro-ethane / 1 h / Heating 4: 21 g / lithium hydroxide monohydrate / H2O; ethanol / 1.5 h / Heating View Scheme

potassium carbonate in N,N-dimethyl-formamide T=0 - 20°C; Inert atmosphere;