Short-RInChIKey=SA-FUHFF-UHFFFADPSC-GWVLJZRVEA-UHFFFADPSC-NUHFF-NMXFL-NUHFF-ZZZ

In a vial, ethyl 5-[(~{E})-[di(propan-2-yl)amino]diazenyl]-1~{H}-pyrazole-4-carboxylate (300 mg, 1.12 mmol, 1.00 equiv) was dissolved in 50 mL of DMSO and the solution was cooled to 0 °C. Cesium Carbonate (439 mg, 1.35 mmol, 1.20 equiv) and bromomethylbenzene (384 mg, 267 μL, 2.24 mmol, 2.00 equiv) were added and the mixture was stirred first at 21 °C for 2 hours, then at 50 °C for 14 hours. The reaction was quenched with ice water and extracted with ethyl acetate (3 x 50 mL). The combined organic layers were washed with brine and dried over Na2SO4 and filtered.