<sup>13</sup>C-NMR. Spectral Differences between Corresponding Methyl Esters, Phenyl Esters and 2-Substituted Chromones
作者:Urs Séquin
DOI:10.1002/hlca.19810640824
日期:1981.12.16
The 13C-NMR. spectra of 2-substitutedchromones (3) are compared with the data of the analogous methyl and phenylesters (1 and 2). The chemical shift differences found are most prominent for the C-atoms in β-position to the ester carbonyl and chromone C(2), respectively. These shift differences are discussed in terms of conformational differencesbetween the esters 1 and 2 and the analogous chromones