1: 91 percent / imidazole / dimethylformamide / 2 h / 0 °C 2: 90 percent / pyridine / CH2Cl2 / 4 h / Ambient temperature 3: 1.) p-toluenesulfonic acid, 2.) 20percent aq. HCl / 1.) CH3OH, RT, 1.5 h, 2.) CH3OH, RT, 2 h View Scheme