3,5-Dichlorobenzenesulfonyl chloride → 6-(3,5-Dichloro-phenylsulphonylamino)-naphthalene-1-carboxylic acid

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Reaction Steps

2.68 g 3,5-dichloro-phenylsulphonyl chloride are added to 2.00 g of 6-amino-naphthalene-1-carboxylic acid in 10 ml of pyridine while cooling with an ice bath. The reaction mixture is left overnight to come up to ambient temperature and then the pyridine is distilled off in vacuo using the rotary evaporator. The flask residue is acidified with 3 N hydrochloric acid and extracted with ethyl acetate/methanol. The combined extracts are washed with water, dried on magnesium sulphate and evaporated down. The crude product is purified by chromatography through a silica gel column with cyclohexane/ethyl acetate (65:35 to 0:100) as eluant.

Provenance & Evidence