Short-RInChIKey=SA-FUHFF-UHFFFADPSC-DMRAVMAMSL-UHFFFADPSC-NUHFF-NUHFF-NUHFF-ZZZ

In a vial, 3-azido-1-(4-methylbenzyl)-1H-pyrazole-4-carbonitrile (56.3 mg, 236 μmol, 1.00 equiv) was dissolved in THF (4.00 mL) and water (4.00 mL) (1:1) and copper;sulfate (7.54 mg, 47.3 μmol, 0.20 equiv), sodium ascorbate (46.8 mg, 236 μmol, 1.00 equiv) and methyl 4-ethynylbenzoate (49.2 mg, 307 μmol, 1.30 equiv) were added. The reaction mixture was stirred at 50 °C for 16 hours. For workup, the reaction mixture was diluted in water and extracted three times with methylene chloride. The combined organic phases were washed with water and brine, dried over Na2SO4, filtered and the solvent was removed under reduced pressure.