Pyrazole → 4-[5(4-chlorophenyl)-1H-pyrazol-1-yl]benzenesulfonamide

Participants

Reaction Steps

3-[4-(Chloro)phenyl]-propane-1,3-dione from Step 1 (18.3 g, 0.1 mol) and 4-sulfonamidophenylhydrazine hydrochloride (22.4 g, 0.1 mol) were dissolved in 150 mL of absolute ethanol and heated to reflux for 16 hours. The solution was cooled to room temperature, diluted with 100 mL of water and let stand, whereupon crystals of pyrazole formed that were isolated by filtration to provide 8.4 g (25%) of a white solid: mp 185°-187° C.; 1H NMR (CDCl3/300 MHz) 7.89 (d, J=8.7Hz, 2H), 7.76 (d, J=1.8Hz, 1H), 7.43 (d,J=8.7Hz, 2H), 7.34 (d, J=8.7Hz, 2H), 7.17 (d, J=8.7Hz, 2H), 6.53 (d, J=1.8Hz, 1H), 4.93 (brs 2H). Anal. Calc'd for C15H12N3SO2Cl: C, 53.97; H, 3.62; N, 12.59. Found: C, 54.08; H, 3.57; N, 12.64.

Provenance & Evidence