To a stirred solution of 3-[N-benzyloxycarbonyl-N-(1-oxido-2-pyridinyl)-amino] propanol (3 g, 9.92 mmol) and triethylamine (1.2 g, 11.91 mmol) in anhydrous dichloromethane, kept at 0° C. under nitrogen atmosphere, methanesulfonyl chloride (1.36 g, 11.91 mmol) was added, the reaction was allowed to warm to room temperature and stirred for 1 h. The mixture was washed with ice-water, dried with sodium sulfate, filtered and concentrated to give 2.17 g (61%) of 3-[N-benzyloxycarbonyl-N-(1-oxido-2-pyridinyl)amino]-propyl methanesulfonate which, when required, was purified by flash chromatography (dichloromethane/methanol 95:5).
