Kost-Sagitullin rearrangements

By analogy with the conversion of 1,2-dialkylpyridinium salts into 2-alkylaminopyridines known as the Kost-Sagitullin rearrangement, the pyridinium salt 252 was treated with two different hydrazides (Equation 33). The [l,2,4]triazolo[4,3-tf]-pyridines 253 with Y = 4-pyridyl and NH2 were obtained with 35% and 38% yields, respectively <2003CHE275>. 

Kost-Sagitullin rearrangement in the pyridine, pyrazine, and pyrimidine series 92MI27. 

The recyclizations of the pyridinium salts 236 to form the aniline derivatives 238, called the Kost—Sagitullin rearrangement, occur in the presence of bases via ring-opened intermediate 237338,339 (equation 95). 

Kost-Sagitullin rearrangement and other isomerization recyclization of pyriymidines 05KGS1445. 

---