To a precooled (0° C.) solution of 4-(3-tert-butoxycarbonylamino-propoxy)-2,6-bis-(hydroxymethyl)-pyridine (76 mg) in dichloromethane (0.7 mL), was added a solution of potassium hydroxide (30 mg) in water (0.3 mL). Tosyl chloride (93.7 mg) was added, and the resulting heterogenous mixture was shaken vigorously for 1 h and then washed into separatory funnel using dichloromethane and water. The layers were separated, and the aqueous layer was extracted three times with dichloromethane. The combined organic solutions were dried over magnesium sulfate, and concentrated in vacuo to a residue. The residue was purified by silica gel chromatography (Interchrom Puriflash 10 g column, SiOH 15-35 μm), using gradient elution with a mixture of heptane (A) and ethyl acetate (B) (gradient: 90% A:10% B up to 50% A:50% B) to give 4-(3-tert-butoxycarbonylamino-propoxy)-2,6-bis-(tosyloxymethyl)pyridine (56 mg):
