[Synthesis]
B. Synthesis of 4-bromo-1-methyl-3-phenyl-1H-pyrazole and 4-bromo-1-methyl-5-phenyl-1H-pyrazole. 1-Methyl-3-phenyl-1H-pyrazole and 1-methyl-5-phenyl-1H-pyrazole (1.0 g, 6.3 mmol) were mixed with N-bromosuccinimide (NBS, 1.1 g, 6.3 mmol) in acetonitrile (25 mL), stirred and heated to 70 °C for 1 h of reaction. After completion of the reaction, the reaction solution was concentrated and the crude product was purified by column chromatography using hexane-ethyl acetate gradient elution (from 100% hexane to 25% ethyl acetate in hexane solution) to afford 4-bromo-1-methyl-3-phenyl-1H-pyrazole (504 mg, 34% yield) and 4-bromo-1-methyl-5-phenyl-1H-pyrazole (295 mg, 20% yield), respectively. ). 1H NMR (400 MHz, DMSO-d6): δ 8.01 (s, 1H), 7.95 (d, 2H), 7.41 (t, 2H), 7.38 (d, 1H), 3.85 (s, 3H); 1H NMR (400 MHz, DMSO-d6): δ 7.63 (s, 1H), 7.50 (m, 5H), 3.77 ( s, 3H). |