An analysis of substituent effects on 1H and 13C NMR parameters of substituted furans. Linear free energy relationships and PM3 semiempirical calculations

1998 ◽  
pp. 679-690 ◽  
Author(s):  
Carlos Alvarez-Ibarra ◽  
María L. Quiroga-Feijóo ◽  
Emilio Toledano
Keyword(s):  
Free Energy ◽  
13C Nmr ◽  
Substituent Effects ◽  
Linear Free Energy Relationships ◽  
1H And 13C Nmr ◽  
Nmr Parameters ◽  
Linear Free Energy ◽  
Energy Relationships ◽  
Substituted Furans ◽  
Pm3 Semiempirical Calculations

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

Substituent effects on the N.M.R. spectra of carboxylic acid derivatives. III. Correlation of 13C N.M.R. spectra of para substituted acetanilides and 4'-nitrophenyl 4-substituted benzoates with infrared carbonyl stretching frequencies, 1H N.M.R., rate and equilibrium data

1984 ◽  
Vol 37 (3) ◽  
pp. 497 ◽  
Author(s):  
CJ O'Conner ◽  
DJ McLennan ◽  
DJ Calvert ◽  
TD Lomax ◽  
AJ Porter ◽  
...  
Keyword(s):  
Free Energy ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Linear Free Energy Relationships ◽  
Reactive Site ◽  
Linear Free Energy ◽  
Equilibrium Data ◽  
Energy Relationships ◽  
Monosubstituted Benzenes ◽  
Best Fit

The 13C n.m.r. spectra of 17 monosubstituted benzenes, 14 para substituted acetanilides and ten 4'-nitrophenyl 4-substituted benzoates have been measured in (CD3)2SO and the chemical shifts have been compared with the infrared carbonyl stretching frequencies of the substrates (in CCl4), the 1H n.m.r. chemical shifts of protons close to the reactive site of protonation, rates of hydrolysis or aminolysis and literature values of the corresponding basicity constants and rate constants. The observed substituent chemical shifts are non-additive and this result has been discussed in terms of the electronic properties of -NHCOCH3 and -COOC6H4NO2. The 13C n.m.r. and the i.r. data have been treated by single parameter and dual substituent parameter linear free energy relationships and σR values of best fit have been identified. Relative resonance and inductive contributions have been discussed.

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.

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