Studies on Sulfisoxazole. IX

Application of hydroxylamine to N-(p-acetamido- or p-amino-benzenesulfonyl)-2-acetylpropionamide (Ia or Ib) gives their oximes (IIa or IIb) and dehydrative cyclization of these oximes with chlorosulfonic acid as the dehydrative agent in glacial acetic acid affords 5-(p-acetamido- or p-amino-benzenesulfonamido)-3, 4-dimethylisoxazole (IIIa or IIIb), which were confirmed by admixture and ultraviolet spectral comparison with the products obtained by the reaction of N-(p-acetamido- or p-amino-benzenesulfonyl)-2-acetylpropionamidine (VI) and hydroxylamine, and also by preparation of p-aminomethylbenzenesulfonamide derivatives. Formation of oxime of 2-acetylpropionamide (VIII) and cyclization of this oxime were examined and it was found that although the oxime is formed easily, its reductive cyclization to 3, 4-dimethyl-5-aminoisoxazole was not effected and a different substance of m. p. 110-112° was obtained.