Conformational analysis XX—13C NMR studies of saturated heterocycles 5—substituent effects on the13C chemical shifts of methyl substituted 1,3-dithiolanes

1981 ◽  
Vol 17 (4) ◽  
pp. 246-249 ◽  
Author(s):  
Kalevi Pihlaja ◽  
Mauri Eskonmaa ◽  
Raimo Keskinen ◽  
Alpo Nikkilä ◽  
Timo Nurmi
Keyword(s):  
Conformational Analysis ◽  
13C Nmr ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Nmr Studies ◽  
Saturated Heterocycles

ChemInform Abstract: THE CONFORMATIONAL ANALYSIS OF SATURATED HETEROCYCLES PART 56, SUBSTITUENT EFFECTS IN THE CONFORMATIONAL EQUILIBRIA OF SPIRO-OXAZOLINES

1974 ◽  
Vol 5 (20) ◽  
pp. no-no
Author(s):  
RICHARD A. Y. JONES ◽  
ALAN R. KATRITZKY ◽  
KEITH A. F. RECORD ◽  
ROGER SCATTERGOOD ◽  
JOHN M. SULLIVAN
Keyword(s):  
Conformational Analysis ◽  
Substituent Effects ◽  
Conformational Equilibria ◽  
Saturated Heterocycles

13C-NMR-Spektroskopie an polycyclischen Aromaten, IIΙ Die 13C-NMR-Spektren von Amino- und Dimethylaminonaphthalinen /13C NMR Spectroscopy of Polycyclic Aromatics, III The 13C NMR Spectra of Amino- and Dimethylaminonaphthalenes

1975 ◽  
Vol 30 (9-10) ◽  
pp. 794-799 ◽  
Author(s):  
Ludger Ernst
Keyword(s):  
13C Nmr ◽  
High Field ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Double Resonance ◽  
Substituent Effects ◽  
13C Nmr Spectroscopy ◽  
Polycyclic Aromatics ◽  
Electrophilic Reagents ◽  
C Nmr

The 13C NMR spectra of twelve amino-, dimethylamino-, diamino-, and bis(dimethylamino)naphthalenes are completely assigned by selective 13C{1H} double resonance and by interpretation of proton-coupled spectra. Strong substituent effects (Δδ) upon chemical shifts are observed and can largely be accounted for by mesomerism. The pronounced high-field shifts of C-6 in the 2-amino- and 2-dimethylaminonaphthalenes coincide with the enhanced reactivity of this position towards electrophilic reagents. In 1-dimethylaminonaphthalene and even more so in 1-dimethylamino-2-methylnaphthalene, conjugation is inhibited for steric reasons and Δδ’s are greatly diminished, thus giving an estimate for the contribution of resonance to substituent-induced shifts in the unhindered compounds. In two 1,8-disubstituted naphthalenes there are large deviations from additivity of substituent effects.

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