Structure-kinetics relations holding in the amination of six-membered nitrogen-containing heterocyclic compounds

Abstract

Relative rates of the amination of 3-X-and 4-X-substituted pyridines (X = H, 3-Me, 4-Me, 3-F 3 C, 3-CN, 4-CN, 3-Cl, 3-Br, 4-MeO, 4-Me 2 N), pyrazine, quinoline, isoquinoline, 2,2′-and 4,4′-bipyridines, and 1,10-phenanthroline with O-mesitylenesulfonylhydroxylamine were estimated by NMR spectroscopy. Correlations were found between logarithms of the relative amination rate constants and substituent constants σ or σ I and σ R for X-substituted pyridines. A wide series of nitrogen-containing heterocyclic compounds turned out to fit correlations between logarithms of the relative amination rate constants, on the one hand, and relative stabilities of N-aminoazinium cations, energies of activation of the amination process, and gas-phase proton affinities, calculated by the DFT/PBE/3z and DFT/B3LYP/L2 methods, on the other.