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Correlation of oxygen‐17 substituent‐induced chemical shifts: Meta ‐ and para ‐substituted methyl benzoates
Author(s) -
Exner Otto,
Dahn Hans,
Péchy Péter
Publication year - 1992
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260300505
Subject(s) - substituent , chemistry , benzoates , oxygen , acetonitrile , medicinal chemistry , chemical shift , organic chemistry
Oxygen‐17 NMR spectra of 45 substituted methyl benzoates in acetonitrile were measured at natural abundance. The substituent‐induced chemical shifts (SCS) of the carbonyl oxygen correlate well with the σ m and σ p +substituent constants in two separate correlations for meta and para derivatives; principal component analysis (PCA) is only slightly better [particularly for the N(CH 3 ) 2 substituent]. The 17 O SCS generally depend on the same factors as the 13 C SCS of the β‐carbon of alkenes, provided comparison is made between compounds of similar polarity. SCS of the methoxyl oxygen depend less precisely on σ m or σ p , with some unexplained deviations.