scholarly journals Correlation analysis of IR, 1H and 13C NMR spectral data of N-alkyl and N-cycloalkyl cyanoacetamides

2011 ◽  
Vol 17 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Aleksandar Marinkovic ◽  
Jelena Nedeljkovic ◽  
Dusan Mijin ◽  
Natasa Ilic ◽  
Slobodan Petrovic
Keyword(s):  
Spectral Data ◽  
13C Nmr ◽  
Ethyl Cyanoacetate ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Steric Interaction ◽  
1H And 13C Nmr ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Reverse Substituent Effect

Linear free energy relationships (LFER) were applied to the IR, 1H and 13C NMR spectral data in Nalkyl 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 ? values for several correlations (reverse substituent effect) were found.

scholarly journals Substituent effect on IR, 1H and 13C NMR spectral data in n-(substituted phenyl)-2-cyanoacetamides: A correlation study

2013 ◽  
Vol 19 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Aleksandar Marinkovic ◽  
Dominik Brkic ◽  
Jelena Martinovic ◽  
Dusan Mijin ◽  
Milos Milcic ◽  
...  
Keyword(s):  
Spectral Data ◽  
13C Nmr ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Spectroscopic Studies ◽  
Correlation Study ◽  
1H And 13C Nmr ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Ir Spectroscopic

Linear free energy relationships (LFER) were applied to the IR, 1H and 13C NMR spectral data of N-(substituted phenyl)-2-cyanoacetamides. A variety of substituents were employed for phenyl substitution and fairly good correlations were obtained using the simple Hammett and the Hammett-Taft dual substituent parameter equations. The correlation results of the substituent induced 13C NMR chemical shifts (SCS) of the C1, C=O and N-H atom indicated different sensitivity with respect to electronic substituent effects. A better correlation of the SCSC=O with a combination of electrophilic and nucleophilic substituent constants indicated a significant contribution of extended resonance interaction (?-delocalization) within the ?1-unit. The conformations of the investigated compounds were studied using the DFT B3LYP/6-311G method and, together with the results of 13C NMR and IR spectroscopic studies, a better insight into the influence of such a structure on the transmission of electronic substituent effects was obtained.

Linear free energy relationships of the 1H and 13C NMR chemical shifts of 3-methylene-2-substituted-1,4-pentadienes

2005 ◽  
Vol 744-747 ◽  
pp. 901-908
Author(s):  
Nataša V. Valentić ◽  
Željko Vitnik ◽  
Sergei I. Kozhushkov ◽  
Armin de Meijere ◽  
Gordana S. Ušćumlić ◽  
...  
Keyword(s):  
Free Energy ◽  
13C Nmr ◽  
Chemical Shifts ◽  
Linear Free Energy Relationships ◽  
1H And 13C Nmr ◽  
Nmr Chemical Shifts ◽  
13C Nmr Chemical Shifts ◽  
Linear Free Energy ◽  
Energy Relationships

8-Acyl-7-phenylbicyclo[2.2.2]-2,6-diones by rearrangement of 3-acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones. 1H and 13C NMR spectral evidence of their structure

1990 ◽  
Vol 55 (5) ◽  
pp. 1208-1215 ◽  
Author(s):  
Pavel Hrnčiar ◽  
Tibor Liptay ◽  
Ján Šraga
Keyword(s):  
Double Bond ◽  
Spectral Data ◽  
13C Nmr ◽  
1H And 13C Nmr ◽  
Spectral Evidence ◽  
C Nmr

3-Acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones II were prepared by O-acylation of 5-(2-phenylethenyl)-1,3-cycloxanedione (I). Treatment of II with AlCl3 resulted in rearrangement of the acyl group to the double bond of the phenylethenyl grouping followed by cyclization to 8-acyl-7-phenylbicyclo[2.2.2]octane-2,6-diones III. Their structure was evidenced by analysis of the 1H and 13C NMR spectral data.

SYNTHESIS AND CHARACTERIZATION OF HETEROCYCLIC CHALCONES CONTAINING HALOGENATED THIOPHENES

2015 ◽  
Vol 77 (3) ◽  
Author(s):  
Helmi Mohammed Al-Maqtari ◽  
Joazaizulfazli Jamalis ◽  
Hasnah Mohd Sirat
Keyword(s):  
Sodium Hydroxide ◽  
Spectral Data ◽  
13C Nmr ◽  
Basic Medium ◽  
Synthesis And Characterization ◽  
Schmidt Reaction ◽  
Synthetic Compounds ◽  
1H And 13C Nmr ◽  
Heterocyclic Aldehydes

Heterocyclic chalcones containing halogenated thiophenes were synthesized. The first step was to synthesize 3-acetyl-2,5-dichlorothiophene and 2-acetyl-5-chlorothiophene as heterocyclic ketones by using Friedel-Crafts acylation. The ketones were then used to synthesize thiophene chalcones through Claisen-Schmidt reaction with the respective heterocyclic aldehydes such as 5-bromothiophene-2-carbaldehyde, 3-methyl-2-thiophene carboxaldehyde and 2-thiophene carboxaldehyde with 3-acetyl-2,5-dichlorothiophene or 2-acetyl-5-chlorothiophene in presence of basic medium, sodium hydroxide to form the corresponding chalcones. Structures of the synthetic compounds were confirmed by IR, MS, 1H and 13C NMR spectral data.

scholarly journals Effects of substituents on the 1H-NMR chemical shifts of 3-methylene-2-substituted-1, 4-pentadienes

2003 ◽  
Vol 68 (7) ◽  
pp. 525-534 ◽  
Author(s):  
Natasa Valentic ◽  
Gordana Uscumlic
Keyword(s):  
Chemical Shifts ◽  
Substituent Effects ◽  
Electronic Effects ◽  
Resonance Effects ◽  
Charge Densities ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Consistent Picture ◽  
Vinyl Group ◽  
Proton Chemical Shifts

The principle of linear free energy relationships was applied to the 1H chemical shifts of the ?-vinyl proton atoms of 3-methylene-2-substituted-1,4-pentadienes. The correlations of the proton chemical shifts with Swain and Lupton substituent parameters provide a mutually consistent picture of the electronic effects in these compounds. The overall pattern of proton chemical shifts can be largely accounted for by a model of substituent effects based on field, resonance and ? polarization effects. Owing to the particular geometric arrangement of the vinyl group in 3-methylene-2-substituted-1,4-pentadienes, the ?-vinyl protons HB and HC have different sensitivities to polar and resonance effects. The different sensitivities of the 1H chemical shifts to resonance effects reveals some effects not predicted by the model outlined above. Evidence is presented that demonstrates that both the 1H and 13C chemical shifts for these compounds reflect their ground-state charge densities.

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