A convenient synthesis of 2,3,5,6-tetrahalogenopyridines and of 3,5-bis(alkylthio)pyridines from 2,6-diaminopyridine
Abstract
Controlled chlorination of 2,6-diaminopyridine (1) affords 2,6-diamino-3,5-dichloropyridine (2a) which is then bis(diazotised) to give 2,3,5,6-tetrachloropyridine (3a); similarly prepared are other 2,3,5,6-tetra(chloro/bromo)pyridines and 2,6-dichloro-3,5-bis(thiocyanato)pyridine (3h), from which 3,5-bis(alkylthio)pyridines are easily obtained.