A NOVEL REARRANGEMENT OF 2,2'-BIPYRIDINE N,N'-DIOXIDES THE CHARACTERISATION OF DIPYRIDO ISOXAZOLINIUM SALTS AS INTERMEDIATES IN THE FORMATION OF 3-HYDROXY-2,2'-BIPYRIDINES

Article abstract of DOI:10.1016/S0040-4020(01)91821-6

The reactions of 2,2'-bipyridine N,N'-dioxides with POCl3 and SO2Cl2 have been investigated, and the products shown to be synthetically useful halogenated derivatives.The presence of substituents in the 4 position favours an intramolecular cyclisation to form dipyrido<1,2-b:2,3-d>-isoxazolinium salts, which have been characterised for the first time.