New aspects of the nitration of some imidazo[1,2-a]pyridines. CNDO/2 calculations from X-ray structures

Abstract

The reactivity of the imidazo[l,2-a]pyridine system (1) was investigated, CNDO/2 calculations based on X-ray structure determinations of 5-ethoxyimidazo[l,2-a]pyridine (2), ethyl 8-methylimidazo-[1,2-a]pyridine-2-carboxylate (5) and ethyl 6-methyl-3-nitroimidazo[l,2-a]pyridine-2-carboxylate (10c) are compared with experimental results of the nitration of variously substituted imidazo[l,2-a]- pyridines, and are found compatible with the individual reactivities.