Привожу методику:
Methyl azidoacetate (2). This reaction should be performed behind a safety shield. To a solution of methyl bromoacetate (1) (51.5 mL, 0.528 mol) in MeOH (86 mL) in a 500-mL, three-necked, round-bottomed flask equipped with a magnetic stirrer, reflux condenser, a drying tube, a septum through which is passed a metal temperature probe and a 20 °C water bath is added a slurry of sodium azide (42.3 g, 0.649 mol, 1.23 equiv) in H2O (40 mL) via a funnel in one portion. The residual sodium azide is rinsed into the round-bottomed flask with water (2 × 6 mL). The suspension is stirred for 20 min in the water bath and a mild exotherm occurs (Note 2). The solution is then brought to gentle reflux with a heating mantle for 2 h. After cooling to room temperature, the solvent is removed carefully on the rotary evaporator (40 mmHg, 25 °C water bath), as the heterogeneous mixture has a tendency to bump. The residue is partitioned between Et2O (100 mL) and H2O (100 mL), transferred to a separatory funnel and the aqueous phase is further extracted with of Et2O (3 × 30 mL). The combined organic layer is dried with MgSO4, filtered, and evaporated to give methyl azidoacetate (53.9–54.5 g, 89–90%) as a slightly yellow oil.
. Олдрихи продают его почему-то только в виде растворов, видать бояться "БУМа" 
