methanol; toluene-4-sulfonic acid T=20°C; 0.0333333 h; sonication;

1: 80 percent / pyridine / 64 h / 20 °C 2: 80 percent / NBS; K2CO3 / CCl4 / 2 h / Heating 3: 90 percent / NaN3 / dimethylformamide / 14 h / 65 °C 4: 73 percent / NaOMe / methanol / 48 h / 20 °C 5: 25 percent / H2 / Pd/C / methanol / 27 h View Scheme

1: 40 percent / pyridine-sulfur trioxide / pyridine / 41 h / Ambient temperature 2: H2SO4 / methanol; H2O / Ambient temperature View Scheme