The general procedure for the synthesis of 4,4'-((1-phenyl-1H-pyrazole-3,5-diyl)bis(ethylene-2,1-diyl))bis(2-methoxyphenol) using (1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione and phenylhydrazine as starting materials was as follows: curcumin I (1 mmol) was mixed with phenylhydrazine (1 mmol) in an appropriate amount of ethanol. Acetic acid (2 mL) was added to the mixture, followed by microwave radiation (300 W, 2 min), during which heating-cooling cycles were performed every 15 s to prevent solvent evaporation. After completion of the reaction, the mixture was diluted with water (10 mL) and the precipitate was collected by filtration. The crude product was purified by dry column fast chromatography using TLC-grade silica-G as stationary phase and chloroform-ethyl acetate (2:1, v/v) as eluent. After purification, the target compound 3,5-bis[β-(4-hydroxy-3-methoxyphenyl)vinyl]-1-phenylpyrazole (CNB-001) was obtained as a reddish-brown amorphous solid in 87% yield with a melting point of 88-89°C (literature value: 89°C). Elemental analysis (C27H24N2O4) Calculated values: C, 73.62; H, 5.49; N, 6.36. Measured values: C, 73.48; H, 5.61; N, 6.28. Infrared spectra (KBr, cm-1): 3510, 3030, 1595, 1508, 1273, 1029, 960, 761, 696. 1H NMR (300 MHz, CDCl3): δ 3.89 (s, 3H), 3.92 (s, 3H), 5.68 (br s, 2H), 6.71 (d, J = 15.9 Hz, 2H), 6.82-7.14 (m, 9H), 7.33-7.52 (m, 5H). m/z of FAB MS (NBA matrix): 441.58 [M + H] +. Calculated value (C27H24N2O4 + H)+: m/z 441.18.
