Hydrochloric Acid → 4-amino-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide

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Reaction Conditions

Reaction Steps

4-Amino-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide can be obtained in the following way: 1.5 ml of an aqueous 5N hydrochloric acid solution are added to a suspension of 0.3 g of N-[4-(3-phenyl-1H-indazol-5-ylsulfamoyl)-phenyl]acetamide in 6 ml of 95% ethanol. The reaction mixture is then refluxed for 30 minutes then cooled to a temperature in the region of 20° C. 20 ml of water and 1 ml of an aqueous 32% ammonium hydroxide solution are then added to the reaction mixture, which is then extracted successively with 30 ml and 15 ml of ethyl acetate. The organic extracts are pooled, dried over magnesium sulfate, filtered and then concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. The residue thus obtained is purified by chromatography on a silica column (particle size 40-63 μm), eluting with a dichloromethane/methanol (95/5 by volume) mixture. The fractions containing the expected product are pooled and concentrated to dryness under reduced pressure (2 kPa) at a temperature in the region of 40° C. The solid thus obtained is taken up in 9 ml of ethanol in the presence of 3S black and dissolved under hot conditions, and the mixture is filtered under hot conditions through sintered glass and then recrystallized. The crystals are filtered off through sintered glass, washed with 0.5 ml of 95% ethanol then with 2 times 2 ml of diisopropyl ether, partially dried and then dried under reduced pressure (3 kPa) at a temperature in the region of 50° C. 70 mg of 4-amino-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide are thus obtained in the form of a light beige powder melting at 249° C. (CI mass analysis: m/z 365 (M+H)+).

Provenance & Evidence