1: H2 / Pd/C / methanol 2: 51 percent / AcOH / tetrahydrofuran / 48 h / 110 - 120 °C 3: POCl3 / benzene / 1 h / Heating 4: conc. HCl / 0.67 h / Heating 5: Et3N / acetone / 0.25 h / 0 °C 6: 1.) NaN3, 2.) 8 M HCl / 1.) Me2CO, H2O, 0 deg C, 30 min, 2.) reflux, 10 min 7: 83 percent / methanol / 24 h / 20 °C View Scheme

Multi-step reaction with 6 steps 1: H2 / Pd/C / methanol2: 51 percent / AcOH / tetrahydrofuran / 48 h / 110 - 120 °C3: POCl3 / benzene / 1 h / Heating4: conc. HCl / 0.67 h / Heating5: Et3N / acetone / 0.25 h / 0 °C6: 1.) NaN3, 2.) 8 M HCl / 1.) Me2CO, H2O, 0 deg C, 30 min, 2.) reflux, 10 min