A cautionary note on the use of p-nitrobenzenesulfonamides as protecting groups

Article abstract of DOI:10.1016/S0040-4039(98)00684-4

The cleavage of p-nitrobonzenesulfonamides using thiolate was found to give poor regioselectivity. Cleavage requires addition of thiolate at the sulfonamide carbon, but some addition occurs at the nitro carbon resulting in simple displacement of the nitro group rather than sulfonamide cleavage. The side reaction is most prevalent with cyclic amines and steric effects play only a limited role. This lack of regioselectivity is not observed for o- nitrobenzenesulfonamides.