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13C- and 1H-NMR substituent-induced chemical shifts in N(1)-(4-substituted phenyl)-3-cyano-4,6-dimethyl-2-pyridones
Journal of the Serbian Chemical Society , 2008,
Abstract: The 13C- and 1H-NMR chemical shifts of thirteen N(1)-(4-substituted phenyl)-3-cyano-4,6-dimethyl-2-pyridones were measured in deuterated dimethyl sulfoxide (DMSO-d6). The correlation analysis for the substituent-induced chemical shifts (SCS) with sigmap, inductive (sigmaI) and different scale of resonance (sigmaR) parameters were performed using the SSP (single substituent parameter), DSP (dual substituent parameter) and DSP–NLR (dual substituent parameter–non-linear resonance) methods. The results of the calculations concerning the polar and resonance effects satisfactorily describe the substituent effects at the carbon atoms of interest. The mode of transmission of the substituent effects, both inductive and resonance, in relation to the geometry of the investigated pyridones is discussed.
The substituent effects on the 13c chemical shifts of the azomethine carbon atom of n-(phenyl substituted) salycilaldimines  [PDF]
Drmani? Sa?a ?.,Marinkovi? Aleksandar D.,Nikoli? Jasmina B.,Jovanovi? Bratislav ?.
Journal of the Serbian Chemical Society , 2012, DOI: 10.2298/jsc120319033d
Abstract: The Hammett correlations between 13C-NMR chemical shifts of the azomethine carbon atom and the corresponding substituent constants for thirtheen Schiff bases were established. Successful correlation of the chemical shifts with electrophilic substituent constants ó+ indicate significant resonance interaction of the substituents on the aniline ring with the azomethine carbon atom in the examined series of imines. The demand for electrons in the investigated compounds was compared to that of the N-benzylidenanilines and N-(phenyl substituted) pyridinealdimines. The way of transmission of the substituent effects was discussed and they are separated into resonance and inductive effects. Inductive effects prevail over resonance effects.
Chemical Industry and Chemical Engineering Quarterly , 2010,
Abstract: The electron-ionization induced mass spectra of twenty six N-monosubstituted cyanoacetamides were recorded and their fragmentation patterns were stu died. The effect of N-alkyl and N-aryl substituents to the fragmentation of the investigated compounds was discussed. Mechanistic generalization lead to a conclusion that fission of the carbon-carbon bonds next to carbonyl function or nitrogen were processes common for N-alkyl and N-(4-substituted phenyl) cya noacetamides. In some amides, the elimination of the acyl group by a ketene fragment gave rise to the more stable ion. Cycloalkyl amides could not frag ment by single carbon-carbon bond fission, but subsequent rearrangement resulted in formation of stable even electron ion. N-(4-substituted phenyl) cyanoacetamides were more stable showing also characteristic fragmentation depending on substituent present at phenyl ring.
High resolution 1H and 13C NMR and mass spectral studies of substituted dipyridylpyridazine  [PDF]
Arab K. El-Qisairi
Spectroscopy: An International Journal , 2002, DOI: 10.1155/2002/406936
Abstract: Total assignment of the 1H and 13C NMR spectra of 3,6-bis(2'-pyridyl)pyridazine derivatives (n-dppn) have been recorded at 400 and 100 MHz, respectively.1Based on these data, the complete assignment of the 13C NMR chemical shift values was made by a 13C{1H} decoupling. The spectra clearly show that the n-dppn ligands exist in the cis–cis conformation at least in solution. Matrix assisted laser desorption ionization (MALDI) and time-of-flight mass spectrometry (TOFMS) are used to record the mass spectra of the n-dppn ligands. α-Cyano-4-hydroxycinnamic acid (CHCA) matrix promoted the molecular ion detection when 180 pmol of n-dppn is introduced into the TOFMS.
Aleksandar D. Marinkovi?,Jelena Nedeljkovi?,Du?an ?. Mijin,Nata?a Ili?
Chemical Industry and Chemical Engineering Quarterly , 2011,
Abstract: Linear free energy relationships (LFER) were applied to the IR, 1H- and 13C--NMR spectral data in N-alkyl and N-cycloalkyl cyanoacetamides. N-alkyl and N-cycloalkyl cyanocetamides were synthesized from corresponding amine and ethyl cyanoacetate. A number of substituents were employed for alkyl substitution, and fairly good correlations were obtained, using simple Hammett equation. In N-alkyl and N-cycloalkyl cyanoacetamides substituent cause SCS of N-H hydrogen primarily by steric interaction, polar subtituent effect influences SCS shift of C=O carbon, while steric effect of N-alkyl substituent causes IR stretching frequencies of N-H, C=O and CN group. The conformations of investigated compounds have been studied by the use of semiempirical PM6 method, and together with LFER analysis, give a better insight into the influence of such a structure on the transmission of electronic substituent effects. Negative ρ values for several correlations (reverse substituent effect) were found.
Dual Substituent Parameter Modeling of Theoretical, NMR and IR Spectral Data of 5-Substituted Indole-2,3-diones  [PDF]
Ghazwan F. Fadhil,Hanan A. Radhy,Alexander Perjéssy,Mária ?amalíková,Erkki Kolehmainen,Walter M.F. Fabian,Katri Laihia,Zora ?usteková
Molecules , 2002, DOI: 10.3390/71100833
Abstract: Correlations of AM1 and PM3 theoretical data, 13C-NMR substituent chemical shifts (13C-SCS) and IR carbonyl group wave numbers [ν(C3═O)] were studied using dual substituent parameter (DSP) models for 5-substituted indole-2,3-diones. For the C7 atom a reverse substituent effect attributed to extended π-polarization was observed. On the other hand, the DSP approaches for the C3 atom showed normal substituent effects with some contribution of reverse effect supported strongly by 13C-SCS correlations. In the ν(C3═O) and p(C3═O) DSP correlations the field effect contribution predominates over the resonance effect, which justifies the using of earlier suggested vibrational coupling (V-C) model for 5- and 6-substituted indole-2,3-diones.
Synthesis and antimicrobial activity of novel tetrabromo-α,α’-bis(substituted-benzyl)cycloalkanones  [PDF]
Motiur Rahman A.F.M.,Alam Sayed Mohammad,Kadi Adnan A.
Journal of the Serbian Chemical Society , 2012, DOI: 10.2298/jsc110408005m
Abstract: A series of novel tetrabromo-α,α’-bis(substituted-benzyl)-cycloalkanones have been synthesized through a rapid, simple, and efficient methodology in an excellent isolated yield and characterized via IR, NMR (1H 13C NMR, DEPT135, DEPT90) and Mass spectrometry. All compounds have been assayed for in vitro antimicrobial activities against eight bacteria, e. g. Staphylococcus aureus, Bacillus subtilis, and Listeria monocytogenes, Salmonella enteritidis, Pseudomonas aeruginosa, Enterobacter aerogenes, Salmonella typhimurium, and Escherichia coli and five fungi e.g. Botrytis cinerea, Rhizoctonia solani, Fusarium oxysporum, Sclerotonia sclerotiorum, and Phytophthora capsici. They showed strong antibacterial activity than antifungal activities. Compounds 4c, 4d and 4i containing methoxy or chloro substituent on the para or meta position of the phenyl ring showed comparable MIC values to streptomycin and tetracycline standard antibiotics. Among all the tested compounds 4i exhibited good to moderate antifungal activity against all fungal strains used in the present study.
ESI-MS spectra of 3-cyano-4-(substituted phenyl)-6-phenyl-2(1H)-pyridinones  [PDF]
Journal of the Serbian Chemical Society , 2009,
Abstract: Twelve 3-cyano-4-(substituted phenyl)-6-phenyl-2(1H)-pyridinones were investigated by tandem mass spectrometry using positive as well as negative electrospray ionization. The influence of the electron affinity of the substituent and the steric effect on the fragmentation is discussed. Pyridinones with a substituent of low proton affinity show loss of water, HCN or benzene from the pyridinone ring in the first step of MS2 fragmentations. Oppositely, if a substituent with high proton affinity is present on the phenyl ring in the 4-position of pyridinone, the fragmentation paths are complex, depending mainly on the substituent proton acceptor ability. Elimination of neutral molecules CO, HCN, H2O, PhH (benzene) or Ph and CN radicals are fragmentation processes common for all compounds in the subsequent steps of the fragmentations.
Effect of substituents on the 13C-NMR chemical shifts of 3-methylene-4-substituted-1,4-pentadienes. Part I.
Journal of the Serbian Chemical Society , 2003,
Abstract: The principles of linear free energy relationships were applied to the 13C substituent chemical shifts (SCS) of the carbon atoms in the unsaturated chain of 3-methylene-4-substituted-1,4-pentadienes. Correlations of the SCS with the substituent parameters of Swain and Lupton provide a mutually consistent picture of the electronic effects in these compounds. The pattern of the electronic effects can be fully rationalized by a model based on the direct transmission of substituent effects through-space (direct through-space field effects), and via conjugative interactions (resonance effects), or by substituent-induced polarization of the p-system in the unsaturated chain (p-polarization effect). Semi-empirical MNDO-PM3 calculations suggest the s-cis conformation of 3-methylene-4-substituted-1,4- -pentadienes as the one with minimal heat of formation.
Synthesis of Substituted Phenyl N-(2-hydroxybenzyl)-N-Methylcarbamates  [PDF]
Old?ich Hrabík,Petr ?im?nek,Jaromír Mindl,Jaromír Kaválek
Molecules , 2002, DOI: 10.3390/70200200
Abstract: Thirteen previously unreported substituted phenyl N-(2-hydroxybenzyl)-Nmethylcarbamates were prepared by the reaction of substituted 2-hydroxybenzyl-Nmethylamines with phenyl chlorocarbonates. They were identified by their 1H- and 13C-NMR spectra.
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