To a stirred mixture of diethyl azodicarboxylate (40 wt% toluene solution, 5 mL, 11.5 mmol, 1 eq.) and ether (25 mL) was slowly added an ether solution (25 mL) of morpholine (1.98 mL, 23 mmol, 2 eq.) through a dropping funnel at 0 °C, the dropwise addition process continued for 3 hours. The reaction mixture was then continued to stir for 2 hours under slow warming to room temperature. The resulting yellow precipitate was collected by vacuum filtration, washed with cold ether and dried over a filter to afford azodicarbonyl dimorpholine (ADDM) as a yellow-orange solid (1.62 g, 55% yield). The NMR hydrogen spectrum (CDCl3, 400 MHz) data were as follows: δ 3.61 (multiple peaks, 4H, 2 × CH2), 3.74 (multiple peaks, 8H, 4 × CH2), 3.83 (multiple peaks, 4H, 2 × CH2).
