4-Hydrazinylbenzenesulfonamide hydrochloride → 4,5-dihydro-4-[3-(trifluoromethyl)-1H-benz[g]indazol-1-yl]benzenesulfonamide

Beteiligte Stoffe

Reaktionsschritte

A 100 mL one neck round bottomed flask equipped with reflux condenser, nitrogen inlet and provisions for magnetic stirring was charged with 3,4-dihydro-2-[2,2,2-trifluoro-1-hydroxyethylidene]-1(2H)-naphthalenone from Step 1 (1.21 g, 5.0 mmol), 4-sulfonamidophenylhydrazine hydrochloride (1.12 g, 5.0 mmol) and 25 mL of absolute ethanol. The solution was warmed to reflux for 15 hours, cooled and concentrated in vacuo. The residue was dissolved in ethyl acetate, washed with water and with brine, dried over anhydrous MgSO4, filtered and reconcentrated in vacuo. The residue was recrystallized from a mixture of ethyl acetate and isooctane to give 1.4 g (71%) of pure 4,5-dihydro-4-[3-(trifluoromethyl)-1H-benz[g]indazol-1-yl]benzenesulfonamide: mp 257°-258° C.; 1H NMR (CDCl3 /CD3OD, 4:1) δ 2.7 (m, 2H), 2.9 (m, 2H), 6.6 (m, 1H), 6.9 (m, 1H), 7.1 (m, 1H), 7.16 (m, 1H), 7.53 (m, 2H), 7.92 (m, 2H); 19F NMR CDCl3 δ-62.5. FAB-MS M+H=394.

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