• Reagent for formation of 4-nitrobenzenesulfonyl ('Nosyl', Ns) derivatives of alcohols and amines. Nosylamides, formed from amines in the presence of, e.g. triethylamine, are stable to strong acids and bases, but are selectively cleaved by thiolates, e.g. PhSH or mercaptoacetate: Tetrahedron Lett., 36, 6373 (1995). See also 2-isomer (preceding entry).