thionyl chloride T=20°C; 5 h;

hydrogenchloride in methanol

1.1: hydroxylamine-o-sulphonic acid; water; formic acid / 5.05 h / Reflux 1.2: 20 °C / pH 7 / Cooling with ice 2.1: water / 6 h / 110 °C 2.2: 0.33 h / Cooling with ice 3.1: thionyl chloride / -10 - 20 °C View Scheme

1.1: water / 6 h / 110 °C 1.2: 0.33 h / Cooling with ice 2.1: thionyl chloride / -10 - 20 °C View Scheme

1: 56 percent / TEA; BOP-Cl / CH2Cl2 2: 1M aq. LiOH / tetrahydrofuran / 4 h / 20 °C 3: TEA; BOP-Cl / CH2Cl2 4: 78 percent / H2 / 10 percent Pd/C / methanol / 6 h / 760 Torr View Scheme