1: (dimethylamino)pyridine / acetonitrile 2: 89 percent / tributyltin hydride, AIBN / toluene / 120 °C 3: 50 percent / LiN3, benzoic acid / dimethylformamide / 16 h / 120 °C 4: 82 percent / 0.1 M NaOCH3 / methanol View Scheme