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Investigation of benzimidazoles. III—transmission of the substituent effects in 2-substituted 1-methylbenzimidazoles studied by 13C nuclear magnetic resonance |
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| Authors: | V. A. Lopyrev L. I. Larina T. I. Vakul'skaya E. F. Shibanova I. A. Titova M. G. Voronkov E. E. Liepin'sh |
| Abstract: | The influence of substituents on the 13C NMR chemical shifts of 2-substituted 1-methylbenzimidazoles has been investigated. The electronic effects of the substituents are transmitted to C-4 and C-7 mainly by the resonance mechanism, and to C-5, C-6 and N-CH3, by approximately equal contributions of the resonance and inductive components. A critical analysis of the share in the transmission of substituent effects through the ‘pyridine-type’ and ‘pyrrole-type’ nitrogen atoms is given. |
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