Linear Free-Energy Relationships Applied to the C-13 NMR Chemical Shifts in 4-Substituted N-[1-(Pyridine-3-and-4-yl)ethylidene]anilines
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2014
Authors
Rančić, MilicaTrišović, Nemanja P.
Milčić, Miloš K.
Jovanović, Maja
Jovanovic, Bratislav
Marinković, Aleksandar
Article (Published version)
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Two series of 4-substituted N-[1-(pyridine-3- and -4-yl)ethylidene]anilines have been synthesized using different methods of conventional and microwave-assisted synthesis, and linear free-energy relationships have been applied to the C-13 NMR chemical shifts of the carbon atoms of interest. The substituent-induced chemical shifts have been analyzed using single substituent parameter and dual substituent parameter methods. The presented correlations describe satisfactorily the field and resonance substituent effects having similar contributions for C1 and the azomethine carbon, with exception of the carbon atom in para position to the substituent X. In both series, negative values have been found for C1 atom (reverse substituent effect). Quantum chemical calculations of the optimized geometries at MP2/6-31G++(d,p) level, together with C-13 NMR chemical shifts, give a better insight into the influence of the molecular conformation on the transmission of electronic substituent effects. Th...e comparison of correlation results for different series of imines with phenyl, 4-nitrophenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl group attached at the azomethine carbon with the results for 4-substituted N-[1-(pyridine-3- and -4-yl)ethylidene]anilines for the same substituent set (X) indicates that a combination of the influences of electronic effects of the substituent X and the (1)-unit can be described as a sensitive balance of different resonance structures.
Source:
Journal of Heterocyclic Chemistry, 2014, 51, 5, 1442-1451Publisher:
- Wiley-Blackwell, Hoboken
Funding / projects:
- Study of the Synthesis, Structure and Activity of Natural and Synthetic Organic Compounds (RS-172013)
DOI: 10.1002/jhet.1752
ISSN: 0022-152X
WoS: 000342746900035
Scopus: 2-s2.0-85028227018
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Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Rančić, Milica AU - Trišović, Nemanja P. AU - Milčić, Miloš K. AU - Jovanović, Maja AU - Jovanovic, Bratislav AU - Marinković, Aleksandar PY - 2014 UR - https://cherry.chem.bg.ac.rs/handle/123456789/1857 AB - Two series of 4-substituted N-[1-(pyridine-3- and -4-yl)ethylidene]anilines have been synthesized using different methods of conventional and microwave-assisted synthesis, and linear free-energy relationships have been applied to the C-13 NMR chemical shifts of the carbon atoms of interest. The substituent-induced chemical shifts have been analyzed using single substituent parameter and dual substituent parameter methods. The presented correlations describe satisfactorily the field and resonance substituent effects having similar contributions for C1 and the azomethine carbon, with exception of the carbon atom in para position to the substituent X. In both series, negative values have been found for C1 atom (reverse substituent effect). Quantum chemical calculations of the optimized geometries at MP2/6-31G++(d,p) level, together with C-13 NMR chemical shifts, give a better insight into the influence of the molecular conformation on the transmission of electronic substituent effects. The comparison of correlation results for different series of imines with phenyl, 4-nitrophenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl group attached at the azomethine carbon with the results for 4-substituted N-[1-(pyridine-3- and -4-yl)ethylidene]anilines for the same substituent set (X) indicates that a combination of the influences of electronic effects of the substituent X and the (1)-unit can be described as a sensitive balance of different resonance structures. PB - Wiley-Blackwell, Hoboken T2 - Journal of Heterocyclic Chemistry T1 - Linear Free-Energy Relationships Applied to the C-13 NMR Chemical Shifts in 4-Substituted N-[1-(Pyridine-3-and-4-yl)ethylidene]anilines VL - 51 IS - 5 SP - 1442 EP - 1451 DO - 10.1002/jhet.1752 ER -
@article{ author = "Rančić, Milica and Trišović, Nemanja P. and Milčić, Miloš K. and Jovanović, Maja and Jovanovic, Bratislav and Marinković, Aleksandar", year = "2014", abstract = "Two series of 4-substituted N-[1-(pyridine-3- and -4-yl)ethylidene]anilines have been synthesized using different methods of conventional and microwave-assisted synthesis, and linear free-energy relationships have been applied to the C-13 NMR chemical shifts of the carbon atoms of interest. The substituent-induced chemical shifts have been analyzed using single substituent parameter and dual substituent parameter methods. The presented correlations describe satisfactorily the field and resonance substituent effects having similar contributions for C1 and the azomethine carbon, with exception of the carbon atom in para position to the substituent X. In both series, negative values have been found for C1 atom (reverse substituent effect). Quantum chemical calculations of the optimized geometries at MP2/6-31G++(d,p) level, together with C-13 NMR chemical shifts, give a better insight into the influence of the molecular conformation on the transmission of electronic substituent effects. The comparison of correlation results for different series of imines with phenyl, 4-nitrophenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl group attached at the azomethine carbon with the results for 4-substituted N-[1-(pyridine-3- and -4-yl)ethylidene]anilines for the same substituent set (X) indicates that a combination of the influences of electronic effects of the substituent X and the (1)-unit can be described as a sensitive balance of different resonance structures.", publisher = "Wiley-Blackwell, Hoboken", journal = "Journal of Heterocyclic Chemistry", title = "Linear Free-Energy Relationships Applied to the C-13 NMR Chemical Shifts in 4-Substituted N-[1-(Pyridine-3-and-4-yl)ethylidene]anilines", volume = "51", number = "5", pages = "1442-1451", doi = "10.1002/jhet.1752" }
Rančić, M., Trišović, N. P., Milčić, M. K., Jovanović, M., Jovanovic, B.,& Marinković, A.. (2014). Linear Free-Energy Relationships Applied to the C-13 NMR Chemical Shifts in 4-Substituted N-[1-(Pyridine-3-and-4-yl)ethylidene]anilines. in Journal of Heterocyclic Chemistry Wiley-Blackwell, Hoboken., 51(5), 1442-1451. https://doi.org/10.1002/jhet.1752
Rančić M, Trišović NP, Milčić MK, Jovanović M, Jovanovic B, Marinković A. Linear Free-Energy Relationships Applied to the C-13 NMR Chemical Shifts in 4-Substituted N-[1-(Pyridine-3-and-4-yl)ethylidene]anilines. in Journal of Heterocyclic Chemistry. 2014;51(5):1442-1451. doi:10.1002/jhet.1752 .
Rančić, Milica, Trišović, Nemanja P., Milčić, Miloš K., Jovanović, Maja, Jovanovic, Bratislav, Marinković, Aleksandar, "Linear Free-Energy Relationships Applied to the C-13 NMR Chemical Shifts in 4-Substituted N-[1-(Pyridine-3-and-4-yl)ethylidene]anilines" in Journal of Heterocyclic Chemistry, 51, no. 5 (2014):1442-1451, https://doi.org/10.1002/jhet.1752 . .