4-Hydrazinylbenzenesulfonamide hydrochloride → 4-[4,5-Dihydro-7-methyl-3-(trifluoromethyl)-1h-benz[g]indazol-1-yl]benzenesulfonamide

Participants

Reaction Steps

4-Sulfonamidophenylhydrazine hydrochloride (1.80 g, 8.0 mmol) was added to a stirred solution of the diketone from Step 1 (1.86 g, 7.3 mmol) in ethanol (10 mL). The reaction was heated to reflux and stirred for 14.8 hours. The reaction mixture was cooled and filtered. The filtrate was concentrated in vacuo, dissolved in ethyl acetate, washed with water and with brine, dried over MgSO4 and reconcentrated in vacuo to give the pyrazole as a brown solid (1.90 g, 64%): mp 215°-218° C. 1H NMR (acetone-d6) 300 MHz 8.10 (d, 2H), 7.80 (d, 2H), 7.24 (s, 1H), 6.92 (d, 1H), 6.79 (br s, 2H), 6.88 (d,1H), 3.02 (m, 2H), 2.85 (m, 2H), 2.30 (s, 3H). 19F NMR (acetone-d6) 282 MHz -62.46 (s). High resolution mass spectrum Calc'd. for C19H17F3 O2S: 408.0994. Found: 408.0989.

Provenance & Evidence