1: 71 percent / chromic anhydride-pyridine complex / 24 h / 40 °C 2: NH2OH / ethanol 3: 1) acetic anhydride, pyridine; 2) conc. ammonia / 2) CH3OH 4: CF3COOH / 2 h / 60 °C 5: cc. NH3 / dioxane / 2 h / 60 °C View Scheme