Chemoselective N-nitrosation of secondary amines under mild and heterogeneous conditions via in situ generation of NOCl

A combination of inorganic chloride salts [e.g. WC16, AICl(3) and ZnCl2] an d sodium nitrite in the presence of wet SiO2 were used as an effective nitr osating agent for the nitrosation of secondary amines to their correspondin g nitroso derivatives under mild and heterogeneous conditions in moderate t o excellent yields.