Azido synthesis (via mesyl group): 


A solution of Mesyl coumpound (1.8 g, 0.006 mol) and NaN3 (0.6 g, 0.009 mol) in DMF (6 ml) was stirred at 80°C under N2 gas for 3 h. The reaction mixture was poured into 10% aqueous NaHCO3 (200 ml). The mixture was extracted with methyl t-butyl ether (100 ml x 3). The combined organic layers were washed with brine (50 ml x 3), dried over Na2SO4 and concentrated in vacuo which gave the title azido compound as an orange oil (1.5 g, 95 %).


Patent reference: WO2010016005 (Pfizer)