Synthesis of 3,5-Diphenyl-1H-pyrazole Derivative

In a 100 mL two-neck round-bottom flask(3.84 g, 10 mmol) of compound 7 was swelled in 20 mL THF overnight, then (3.32 mL, 20 mmol) of CHIPA was added at −96 °C (using methanol and liquid nitrogen) as cooling bath, then (3 mL, 15 mmol) of n-BuLi was added drop wise then the reaction mixture was stirred for 1 h under N₂-gas, then 1 mL of TMEDA was added as catalyst and finally (1.24 mL, 20 mmol) of methyl iodide was added drop wise at −40 °C, then the reaction mixture was stirred overnight. The resulting solid was filtered, washed with water, and dried [37 (link),38 ]. Yield: 90%; ¹H NMR (400 MHz, DMSO-d₆) δ (ppm): 7.05–8.22 (m, 13H, Ar-H), 0.98 (t, 3H, CH₃), 1.20 (d, 3H, CH₃), 1.60 (m, 2H, CH₂), 2.55 (m, 1H, CH); ¹³C NMR (400 MHz, DMSO-d₆) δ (ppm): 127.6, 133.5, 122.5, 151.5, 121, 128.8, 164, 161, 128.7, 129.8, 122, 121.9, 147, 175.5, 41, 16.5, 126, 129, 130, 26.5, 12; IR (KBr) ν: 1725 (CO), 3069 (Ar-H), 2989 (aliph-H); Anal. Calcd for C₂₅H₂₂N₂O₃ (398.45): C, 75.36%; H, 5.57%; O, 12.05%; N, 7.03%. Found: C, 75.13%; H, 5.37%; N, 6.92%.