Halogenation of pyridinium-N-(2'-pyridyl)aminide: an easy synthesis of halo-2-aminopyridines

The regioselective halogenatmn of pyrldmium-N-(2’-pyridyljaminide 1 with N-chloro, bromo or iodosuccinimtde under mild conditions IS described. The method, combined with a reductmn of the N-N bond, allows an easy preparation of 5-h& and 3,5-dihalo-Z-aminopyridines 4The authors wish to thank the Comisión Interministerial de Ciencia y Tecnología (C.I.C.Y.T.) for financial support (Project PB90-0284) and to Lilly S. A. for one studentship (C.B.