1.1: pyridine / dichloromethane / 4 h / 25 °C / Inert atmosphere 2.1: toluene-4-sulfonic acid / methanol / 2 h / 25 °C / Inert atmosphere 2.2: 2 h / 25 °C / Inert atmosphere 3.1: sodium azide / N,N-dimethyl-formamide / 48 h / 90 °C / Inert atmosphere 4.1: palladium 10 on activated carbon; hydrogen / methanol / 3 h / 25 °C View Scheme

1: 90 percent / pyridine / CH2Cl2 / 4 h / Ambient temperature 2: 1.) p-toluenesulfonic acid, 2.) 20percent aq. HCl / 1.) CH3OH, RT, 1.5 h, 2.) CH3OH, RT, 2 h View Scheme