Abstract 4 (5)-Bromo-and-iodo-imidazoles, activated by an adjacent nitro substituent, undergo nucleophilic displacement with methoxide, phenoxide, cyclic secondary chines and cyanide. The regiochemistry of the reactions of 5-iodo-4-nitroimidazole with methoxide has been confirmed by spectroscopic and X-ray methods, and a number of erroneous structures from the literature have been revised. Some apparently anomalous reactions of methoxide ...