TY - JOUR
T1 - 13C nuclear magnetic resonance spectroscopy of 6- and 7-substituted coumarins. Correlation with hammett constants
AU - Gottlieb, Hugo E.
AU - De Lima, Roberto Alves
AU - Monache, Franco Delle
PY - 1979
Y1 - 1979
N2 - The 13C n.m.r. spectra of coumarin and 19 6- and 7-substituted derivatives thereof have been obtained and fully assigned. The chemical shifts of the αβ-unsaturated lactone system have been correlated with Hammett constants: C-3 was found to fit very well with σ+, and carbons 2 and 4 with σ. A satisfactory fit was found for the two ring-junction carbons with σp+, but not with σm or σm+. The electronic implications of these relationships are discussed.
AB - The 13C n.m.r. spectra of coumarin and 19 6- and 7-substituted derivatives thereof have been obtained and fully assigned. The chemical shifts of the αβ-unsaturated lactone system have been correlated with Hammett constants: C-3 was found to fit very well with σ+, and carbons 2 and 4 with σ. A satisfactory fit was found for the two ring-junction carbons with σp+, but not with σm or σm+. The electronic implications of these relationships are discussed.
UR - http://www.scopus.com/inward/record.url?scp=37049093304&partnerID=8YFLogxK
U2 - 10.1039/P29790000435
DO - 10.1039/P29790000435
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AN - SCOPUS:37049093304
SN - 1472-779X
SP - 435
EP - 437
JO - Journal of the Chemical Society, Perkin Transactions 2
JF - Journal of the Chemical Society, Perkin Transactions 2
IS - 4
ER -