Step 1: (E)-3-(3,3-Diisopropyltriaz-1-en-1-yl)-1-ethyl-1H-pyrazole-4-carbonitrile (88.7 mg, 357 μmol, 1.00 equiv) was dissolved in 60 mL of dry THF under nitrogen atmosphere. The solution was cooled to 0 °C before lithium aluminum hydride (40.7 mg, 1.07 mL, 1.07 mmol, 1.00M, 3.00 equiv) was added slowly. The cooling was removed and the solution was stirred at 21 °C for 14 hours, then additional 5 hours at 50 °C. The solution was cooled to 21 °C and the reaction was quenched with a saturated K/Na-tartrate solution (60 mL). The organic solvent was removed under reduced pressure and the remaining aqueous phase was extracted with methylene chloride (3x 60 mL). The combined organic layers were washed with brine (150 mL) and dried over Na2SO4. The solvent was removed under reduced pressure to give the crude (E)-(3-(3,3-diisopropyltriaz-1-en-1-yl)-1-ethyl-1H-pyrazol-4-yl)methanamine, which was used for the next step without further purification.Step 2: The crude (E)-(3-(3,3-diisopropyltriaz-1-en-1-yl)-1-ethyl-1H-pyrazol-4-yl)methanamine was dissolved in 60 mL of dry THF under nitrogen atmosphere. The solution was cooled to 0 °C before acetic anhydride (54.7 mg, 50.6 μL, 536 μmol, 1.50 equiv) was added slowly. The cooling was removed and the solution was stirred for 14 hours at 21 °C. The reaction was quenched with a saturated K2CO3-solution (60 mL) and the organic solvent was removed under reduced pressure. The remaining aqueous phase was extracted with methylene chloride (3x 60 mL). The combined organic layers were washed with brine (150 mL) and dried over Na2SO4. The solvent was removed under reduced pressure to give the crude product.
