1: 90 percent / pyridine / 1.) 0 deg C, 1 h 2.) 0 deg C to rt 2: 37 percent / 1 N NaOH / ethanol / 0.25 h / Heating 3: 32 percent / LiN3 / dimethylformamide / 18 h / 120 - 130 °C 4: 83 percent / 80percent HOAc / 0.67 h / 85 - 90 °C View Scheme

1: 90 percent / pyridine / 1.) 0 deg C, 1 h 2.) 0 deg C to rt 2: 59 percent / NaI / 1,2-dimethoxy-ethane / 18 h / Heating 3: 59 percent / 80percent HOAc / 0.83 h / 100 °C View Scheme