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

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Reaction Conditions

Reaction Steps

3-Amino-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide can be obtained in the following way: 0.06 ml of an aqueous hydrochloric acid solution is added to a solution of 0.28 g of 3-nitro-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide in 15 ml of absolute ethanol and 0.3 ml of water. The reaction mixture is refluxed, then 0.12 g of powdered iron is added in small portions. The reaction mixture is refluxed for 2 hours and is then cooled to a temperature in the region of 20° C. 30 ml of water are added to the mixture, which is filtered through Celite®, and the solid is washed with water then ethyl acetate. The filtrate is basified with an aqueous 32% ammonium hydroxide solution to a pH in the region of 12, and is then extracted with 3 times 20 ml of ethyl acetate. The organic extracts are pooled, washed with 3 times 10 ml of water, 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 solid residue is washed successively with diisopropyl ether then dichloromethane, partially dried and dried. 0.12 g of 3-amino-N-(3-phenyl-1H-indazol-5-yl)benzenesulfonamide is thus obtained in the form of an off-white powder melting at 205° C.

Provenance & Evidence