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Proton and 13 C NMR spectra of substituted methyl cyanopropionates: Effects of molecular asymmetry
Author(s) -
Schwarz Meyer,
Bradley Robert B.,
McIntyre H. Michael,
Becker Edwin D.
Publication year - 1974
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270061204
Subject(s) - chemical shift , diastereomer , proton , coupling constant , spectral line , chemistry , crystallography , nmr spectra database , molecule , stereochemistry , proton nmr , nuclear magnetic resonance , physics , organic chemistry , particle physics , quantum mechanics , astronomy
The proton NMR spectra at 220 MHz of two series of substituted cyanopropionates,have been investigated. In addition the 13 C spectra at 15 MHz of the series I were also studied. In I, where the R groups are diastereotopic, differences are observed in the proton chemical shifts of the CH 3 groups in R for R = CH 3 , C 2 H 5 , n ‐C 3 H 7 , i ‐C 3 H 7 , n ‐C 4 H 9 , n ‐C 5 H 11 and n ‐C 6 H 13 . In II [R′ = n ‐C 3 H 7 , CH(CH 3 ) 2 , CH 2 CH(CH 3 ) 2 and C(CH 3 ) 3 ] diastereoisomers are found with substantial differences in chemical shifts between corresponding protons. Coupling constants are interpreted in terms of conformational preferences for certain molecules in both series.