p-Anisidine (TCI)
Sodium Nitrite (Wako)
Sodium Azide (Wako)
Ethyl acetoacetate (TCI)
Sodium hydride (Wako)

To a cold solution of p-anisidine (10 g, 80 mmol) in hydrochloric acid (2 mol/L, 100 mL) was added sodium nitrite (6.3g, 91mmol) dissolved in water (25 mL) dropwise. After being stirred for 30 min at the same temperature, sodium azide (5.4 g, 83 mmol) dissolved in water (25 mL) was added dropwise and the mixture was stirred for one h. The solution was diluted with toluene (50 mL). The organic phase separated was dried over sodium sulfate, filtered and washed with toluene (50 mL). To the filtrate was added ethanol (100 mL), ethyl acetoacetate (10mL, 80 mmol) and sodium hydride (5g, 60% dispersion, 125 mmol) portionwise. After being stirred for 20 h at 80 ^oC, the mixture was evaporated. Hydrochloric acid (2 mol/L, 100 mL) was added to the residue and precipitated solid was filtered, washed with water (100 mL) and dried in vacuo to give the product (15.4 g, 40 mmol, 50%).

The intermediate “4-methoxyphenylazide” is explosive so we used that as a solution without concentration after extraction. Instead of sodium hydride, sodium ethoxide or sodium metal may be used. Sodium ethoxide is not so stable and it is difficult to store for long. Sodium metal is highly reactive. Sodium hydride is much stable and easy to use, but the product contains some mineral oil.

Otto Dimroth, Chemische Berichte, 1902, 1031

HNMR Spectrum of Product