Pyridine系アミンオキシドの一新脱オキシ反応 (補遺)

4-Nitroquinoline 1-OxideとPOBr₃との反応

抄録

1) Reaction of 4-nitroquinoline 1-oxide with phosphorus bromide in chloroform or ethyl acetate proceeds in two directions, (A) and (B), in formula (III). It should be noted here that the N-oxide group is far more active than the 4-nitro group, the reaction chiefly going in the direction of (III-A) while cold and partly to (III-B) when heated.
2) The chief reaction in the desoxidation of 4-nitroquinoline 1-oxide with phosphorus tribromide would be represented by reaction (II) but a side reaction (III) was also found to take place.
3) Reaction of 4-nitropyridine 1-oxide with phosphorus bromide also afforded a small amount of 2-bromo-4-nitropyridine.