Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles
Detailed NMR spectral analysis of DMSO-d6 solutions of the series of substituted 2-phenacylbenzimidazoles (ketimine form, K) reveals two from three tautomeric forms. Integrals of the 1H NMR signals are used in establishing the molar ratio of tautomers. The experimental analyses are supported by quan...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2019-01-01
|
| Series: | Heteroatom Chemistry |
| Online Access: | http://dx.doi.org/10.1155/2019/4364207 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832564153888276480 |
|---|---|
| author | Agnieszka Skotnicka Przemysław Czeleń Ryszard Gawinecki |
| author_facet | Agnieszka Skotnicka Przemysław Czeleń Ryszard Gawinecki |
| author_sort | Agnieszka Skotnicka |
| collection | DOAJ |
| description | Detailed NMR spectral analysis of DMSO-d6 solutions of the series of substituted 2-phenacylbenzimidazoles (ketimine form, K) reveals two from three tautomeric forms. Integrals of the 1H NMR signals are used in establishing the molar ratio of tautomers. The experimental analyses are supported by quantum-chemical calculations, which satisfactorily reproduced the experimental trends. Although the reported semiempirical quantum-chemical calculations show that enaminone E, i.e., 2-(1,3-dihydro-2H-benzo[d]imidazol-2-ylidene)-1-phenylethan-1-one, was thermodynamically most stable, the results of MP2 ab initio calculations reveal the following order of stability: ketimine > enolimine > enaminone (substituents do not affect this sequence). 13C CPMAS NMR spectral data reveal that in the crystalline state the enolimine tautomer O is predominant in the p-CH3 and p-NO2 substituted congeners. |
| format | Article |
| id | doaj-art-d95d2c0e540240e7b2a630b7019e7de1 |
| institution | Kabale University |
| issn | 1042-7163 1098-1071 |
| language | English |
| publishDate | 2019-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Heteroatom Chemistry |
| spelling | doaj-art-d95d2c0e540240e7b2a630b7019e7de12025-02-03T01:11:39ZengWileyHeteroatom Chemistry1042-71631098-10712019-01-01201910.1155/2019/43642074364207Tautomeric Equilibria in Solutions of 2-PhenacylbenzimidazolesAgnieszka Skotnicka0Przemysław Czeleń1Ryszard Gawinecki2Department of Chemistry, UTP University of Science and Technology, Seminaryjna 3, PL-85-326 Bydgoszcz, PolandDepartment of Physical Chemistry, Collegium Medicum, N. Copernicus University, Kurpińskiego 5, 85-950 Bydgoszcz, PolandDepartment of Chemistry, UTP University of Science and Technology, Seminaryjna 3, PL-85-326 Bydgoszcz, PolandDetailed NMR spectral analysis of DMSO-d6 solutions of the series of substituted 2-phenacylbenzimidazoles (ketimine form, K) reveals two from three tautomeric forms. Integrals of the 1H NMR signals are used in establishing the molar ratio of tautomers. The experimental analyses are supported by quantum-chemical calculations, which satisfactorily reproduced the experimental trends. Although the reported semiempirical quantum-chemical calculations show that enaminone E, i.e., 2-(1,3-dihydro-2H-benzo[d]imidazol-2-ylidene)-1-phenylethan-1-one, was thermodynamically most stable, the results of MP2 ab initio calculations reveal the following order of stability: ketimine > enolimine > enaminone (substituents do not affect this sequence). 13C CPMAS NMR spectral data reveal that in the crystalline state the enolimine tautomer O is predominant in the p-CH3 and p-NO2 substituted congeners.http://dx.doi.org/10.1155/2019/4364207 |
| spellingShingle | Agnieszka Skotnicka Przemysław Czeleń Ryszard Gawinecki Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles Heteroatom Chemistry |
| title | Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles |
| title_full | Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles |
| title_fullStr | Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles |
| title_full_unstemmed | Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles |
| title_short | Tautomeric Equilibria in Solutions of 2-Phenacylbenzimidazoles |
| title_sort | tautomeric equilibria in solutions of 2 phenacylbenzimidazoles |
| url | http://dx.doi.org/10.1155/2019/4364207 |
| work_keys_str_mv | AT agnieszkaskotnicka tautomericequilibriainsolutionsof2phenacylbenzimidazoles AT przemysławczelen tautomericequilibriainsolutionsof2phenacylbenzimidazoles AT ryszardgawinecki tautomericequilibriainsolutionsof2phenacylbenzimidazoles |