Hydrochloric Acid → 2-Hydroxy-5-[2-[4-[(2-pyridinylamino)sulfonyl]phenyl]ethenyl]benzoic acid

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Reaction Steps

Isobutyl 2- acetyloxy-5-[2-(4-(chlorosulfonyl)phenyl)ethenyl]benzoate (1.99 g, 0.0046 mol) and 2-pyridinamine (1.3 g, 0.0138 mol) was stirred in dichloromethane (10 ml) at 45° C. for 1 h. After cooling to room temperature dichloromethane (20 ml) and 2M sulfuric acid (20 ml) were added. The precipitated solid (1.3 g) was collected and washed with water. The organic phase was taken to dryness and the residue treated with boiling methanol containing ammonia (2 ml) for 20 min. After cooling 0.6 g was collected which was combined with the first crop. The combined material (1.9 g) was refluxed with potassium hydroxide (1 g) in water (50 ml). After acidification and filtration, the solid residue was dissolved in 70% ethanol with about 3 equivalents of potassium hydroxide at the boiling point and acidified while boiling with hydrochloric acid. After filtration and drying, the yield was 1.25 g (70%).

Provenance & Evidence