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Naryl-substituted anthranilamides with intramolecular hydrogen bonds

Wang, Li-Xia, Hu, Ben-Quan, Xiang, Jun-Feng, Cui, Jie, Hao, Xiang, Liang, Tong-Ling, Tang, Ya-Lin
Tetrahedron 2014 v.70 pp. 8588-8591
chemical reactions, crystal structure, hydrogen bonding, nitrogen, nuclear magnetic resonance spectroscopy, organic compounds, oxygen
Hydrogen bonding interaction as one type of non-covalent force has proven itself to be highly efficient for constructing structurally unique artificial secondary structures. Here, the structure of Naryl-substituted anthranilamide in solution is demonstrated by various NMR technique, the intramolecular hydrogen bonds between amide attached to arylamine of the same ring is proposed, which is supported by its crystal structure in the solid phase. The substituent on the nitrogen atom of arylamine plays an important role in forming the presence of intramolecular hydrogen bonds. The chemical shift of the Naryl-H downfield changes obviously, due to the formation of intramolecular hydrogen bonds and the deshielding effect of oxygen, and the neighboring C–H is activated and shows downfield protonic signal too. The presence of intramolecular hydrogen bonds probably provides the explanation for the transformation from Naryl-substituted anthranilamide to imine, which could be converted into 2-aryl quinazolinone finally.