Nucleophilic Attack on N Aromatics Pyrrole and Pyridine

Imidazole (1) can be considered as having properties similar to both pyrrole and pyridine. In consequence, one would expect that electrophilic reagents would attack the unshared electron pair on N-3, but not that on the pyrrole nitrogen since it is part of the aromatic sextet. The ring carbons, too, are prone to attack by electrophilic, radical and nucleophilic species to a greater or lesser extent substitution reactions which do not destroy the aromatic character are predominant. While the imidazole ring is rather susceptible to electrophilic attack on an annular carbon, it is much less likely to become involved in nucleophilic... 

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