Multi-step reaction with 6 steps 1: sodium hydride / 120 °C2: sulfuric acid; acetic acid / 90 °C3: ethanol; hydroxylamine hydrochloride; sodium / 74 °C4: sodium periodate; sodium acetate / ethanol; water / 60 °C5: triethylamine / dichloromethane / 0 °C6: ammonia / methanol / 20 °C