Thio acid/azide amidation: an improved route to N-acyl sulfonamides

[STRUCTURE: SEE TEXT] A one-pot procedure for the conversion of carboxylic acids to N-acyl sulfonamides, via thio acid/azide amidation, is presented. The method is compatible with acid- and base-sensitive amino acid protection. N-Acyl sulfonamide synthesis on solid support, peptide thio acid/sulfonazide coupling, and N-alkyl amide synthesis via selective cleavage of sulfonyl from an N-alkyl-N-acyl sulfonamide are also reported.