Synthesis of new mono- and dinitroimidazo[1,2-a]pyridines

The study of the nitration of a number of imidazo[1,2-a]pyridines showed that the presence of a strong electron-donating substituent (OH, NH₂) in the molecule is essential for the introduction of two nitro groups into the pyridine ring. On this basis, an approach to the synthesis of previously unknown 5,7- and 6,8-dinitroimidazo[1,2-a]pyridines was elaborated. In the case of electron-withdrawing substituents (Br), the reactions occurred predominantly at position 3 of the heterocyclic system. The obtained nitro derivatives are of interest as a basis for the synthesis of new polyfunctional imidazo[1,2-a]pyridines.