Preparation of 1,5-disubstituted 4-sulfonylpyrazoles, β-cyano-β-sulfonylenamines and 5-substituted 4-sulfonylisoxazoles from β-keto-β-sulfonylenamines

Reaction of β-keto-β-sulfonylenamines 1a,b with N-substituted hydrazines gave 1,5-disubstituted 4-sulfonylpyrazoles 2a-h in moderate yields, which were ring-opened on treatment with n-butyllithium to afford β-cyano-β-sulfonylenamines ( 3a,b,d-f ). 5-Substitued 4-sulfonylisoxazoles 6a-d were also prepared from 1a-d and hydroxylamine.