Sodium Hydroxide → Sulfapyridine

Participants

Reaction Steps

The isolated N-[4-[(2-pyridinylamino)sulfonyl]phenyl]-acetamide was dissolved in 2.5 l of a mixture of ethanol and 1-methoxy-2-propanol (1/1). 105 g (2.66 mol) NaOH was added and the mixture was refluxed for an hour. The reaction mixture was allowed to cool down to room temperature and the solvent was removed under reduced pressure. The residue was dissolved in 1300 ml water and the mixture was acidified to pH 1 using HCl (conc.). The precipitated impurities were removed by filtration and the aqueous fraction was extracted three times with 450 ml methylene chloride. The aqueous fraction was neutralized to pH 7, using a 10 N NaOH solution. 4-amino-N-2-pyridinyl-benzenesulfonamide precipitated from the medium, was isolated by filtration and dried. 93.4 g (70.7%) of 4-amino-N-2-pyridinyl-benzenesulfonamide was isolated.

Provenance & Evidence