Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives
Proton chemical shifts of the following substituted ortho-dimethoxyphenethylamine derivatives: N-2-(2-nitro-4,5-dimethoxyphenyl)ethylphthalimide (1); N-2-(2-nitro-4,5-dimethoxyphenyl)ethylmaleimide (2); 2-nitro-4,5-dimethoxyphenylethylamine (3); N-2-(2-bromo-4,5-dimethoxyphenyl)ethylphthalimide (4);...
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todo:paper_00222860_v881_n1-3_p167_Vitale2023-10-03T14:30:41Z Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives Vitale, A.A. Stahl, A.E. Cecilia dos Santos Claro, P. Alejandra Floridia Addato, M. Pis Diez, R. Jubert, A.H. Density functional calculations Maleimide/phthalimide derivatives Methoxy chemical shifts Substituted dimethoxyphenethylamines Chemical shift Conformations Density functional theory Derivatives Substitution reactions Methoxy chemical shifts Methoxy groups Phthalimide derivatives Substituted dimethoxyphenethylamines Functional groups Proton chemical shifts of the following substituted ortho-dimethoxyphenethylamine derivatives: N-2-(2-nitro-4,5-dimethoxyphenyl)ethylphthalimide (1); N-2-(2-nitro-4,5-dimethoxyphenyl)ethylmaleimide (2); 2-nitro-4,5-dimethoxyphenylethylamine (3); N-2-(2-bromo-4,5-dimethoxyphenyl)ethylphthalimide (4); N-2-(2,3-dinitro-4,5-dimethoxy-phenyl)ethylphthalimide (5); 3,4-dimethoxyphenylethylamine (6), N-2-(3,4-dimethoxyphenyl)ethylmaleimide (7), N-2-(3,4-dimethoxyphenyl)ethylphthalimide (8) were determined in the present work. Significant differences between chemical shifts of methoxy groups of N-2-(2-nitro-4,5-dimethoxyphenyl)ethylphthalimide (1) compared to those of the other studied compounds were found. It is attributed to the differential influence of the phthalimide group on the methoxy groups. Methoxy group (2) is closer to the phthalimide group, so it is shielded by the π system, resulting in a significant lower chemical shift than methoxy group (1). Calculated 1H chemical shifts for some of the above molecules showed that lower-energy conformers play a relevant role to achieve good agreement with experimental data. The inclusion of conformers lying about 2 kcal/mol above the lowest-energy conformer for each molecule reduced dramatically absolute errors in chemical shifts, and allowed the assignment and interpretation of experimental data. © 2007 Elsevier B.V. All rights reserved. Fil:Vitale, A.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00222860_v881_n1-3_p167_Vitale |
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Universidad de Buenos Aires |
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I-28 |
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R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Density functional calculations Maleimide/phthalimide derivatives Methoxy chemical shifts Substituted dimethoxyphenethylamines Chemical shift Conformations Density functional theory Derivatives Substitution reactions Methoxy chemical shifts Methoxy groups Phthalimide derivatives Substituted dimethoxyphenethylamines Functional groups |
| spellingShingle |
Density functional calculations Maleimide/phthalimide derivatives Methoxy chemical shifts Substituted dimethoxyphenethylamines Chemical shift Conformations Density functional theory Derivatives Substitution reactions Methoxy chemical shifts Methoxy groups Phthalimide derivatives Substituted dimethoxyphenethylamines Functional groups Vitale, A.A. Stahl, A.E. Cecilia dos Santos Claro, P. Alejandra Floridia Addato, M. Pis Diez, R. Jubert, A.H. Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| topic_facet |
Density functional calculations Maleimide/phthalimide derivatives Methoxy chemical shifts Substituted dimethoxyphenethylamines Chemical shift Conformations Density functional theory Derivatives Substitution reactions Methoxy chemical shifts Methoxy groups Phthalimide derivatives Substituted dimethoxyphenethylamines Functional groups |
| description |
Proton chemical shifts of the following substituted ortho-dimethoxyphenethylamine derivatives: N-2-(2-nitro-4,5-dimethoxyphenyl)ethylphthalimide (1); N-2-(2-nitro-4,5-dimethoxyphenyl)ethylmaleimide (2); 2-nitro-4,5-dimethoxyphenylethylamine (3); N-2-(2-bromo-4,5-dimethoxyphenyl)ethylphthalimide (4); N-2-(2,3-dinitro-4,5-dimethoxy-phenyl)ethylphthalimide (5); 3,4-dimethoxyphenylethylamine (6), N-2-(3,4-dimethoxyphenyl)ethylmaleimide (7), N-2-(3,4-dimethoxyphenyl)ethylphthalimide (8) were determined in the present work. Significant differences between chemical shifts of methoxy groups of N-2-(2-nitro-4,5-dimethoxyphenyl)ethylphthalimide (1) compared to those of the other studied compounds were found. It is attributed to the differential influence of the phthalimide group on the methoxy groups. Methoxy group (2) is closer to the phthalimide group, so it is shielded by the π system, resulting in a significant lower chemical shift than methoxy group (1). Calculated 1H chemical shifts for some of the above molecules showed that lower-energy conformers play a relevant role to achieve good agreement with experimental data. The inclusion of conformers lying about 2 kcal/mol above the lowest-energy conformer for each molecule reduced dramatically absolute errors in chemical shifts, and allowed the assignment and interpretation of experimental data. © 2007 Elsevier B.V. All rights reserved. |
| format |
JOUR |
| author |
Vitale, A.A. Stahl, A.E. Cecilia dos Santos Claro, P. Alejandra Floridia Addato, M. Pis Diez, R. Jubert, A.H. |
| author_facet |
Vitale, A.A. Stahl, A.E. Cecilia dos Santos Claro, P. Alejandra Floridia Addato, M. Pis Diez, R. Jubert, A.H. |
| author_sort |
Vitale, A.A. |
| title |
Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| title_short |
Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| title_full |
Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| title_fullStr |
Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| title_full_unstemmed |
Experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| title_sort |
experimental and theoretical study of the proton methoxy chemical shifts of substituted 3,4-dimethoxyphenethylamines and maleimide/phthalimide derivatives |
| url |
http://hdl.handle.net/20.500.12110/paper_00222860_v881_n1-3_p167_Vitale |
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