Kinetics of Iodination of 4-Methylimidazole and 2-Methylimidazole

Article abstract of DOI:10.1021/jo01303a035

Since the rate law for the diiodination of imidazole provides information on the iodination of C4(5) but not C2 in the imidazole ring, we have investigated the kinetics of iodination of the two positions separately in 2-methylimidazole and 4-methylimidazole, respectively.The observed rate laws for the methylimidazoles exhibited hydrogen ion dependencies that differed from that of imidazole; the iodinations of all three substrates were base catalyzed, but like imidazole, 2-methylimidazole undergoes uncatalyzed iodination, while 4-methylimidazole does not.The overall rate of iodination of 4-methylimidazole was faster than that of 2-methylimidazole which was faster than that of imidazole.