11.21Write structural formulas for the species formed when a proton is transferred to either of the twonitrogens of imidazole.Protonation of N-1:The species formed on protonation of N-1 is not aromatic. The electron pair of N-1 that contributesto the aromatic 6 p-electron system of imidazole is no longer available for this purpose because it isused to form a covalent bond to the proton in the conjugate acid.Protonation of N-3:The species formed on protonation of N-3 is aromatic. Electron delocalization represented by theresonance forms shown allows the 6 p-electron aromatic system of imidazole to be retained in itsconjugate acid. The positive charge is shared equally by both nitrogens.11.22
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This note was uploaded on 09/26/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.