Substituent Effects on NMR Spectroscopy of 2,2-Dimethylchroman-4-one Derivatives: Experimental and Theoretical Studies

IGUCHI, DANIELA; RAVELLI, DAVIDE; ERRA-BALSELLS, ROSA; BONESI, SERGIO M.

MOLECULES

MOLECULAR DIVERSITY PRESERVATION INTERNATIONAL-MDPI

Año: 2020 vol. 25 p. 1 - 13

1420-3049

Abstract: The attribution of 1H and 13C NMR signals of a library of 5-, 6- and 7-substituted2,2-dimethylchroman-4-one derivatives is reported. Substituent eects were interpreted in termsof the Hammett equation, showing a good correlation for carbons para- to the substituent group,not for the meta- ones. Similarly, the Lynch correlation shows the additivity of the substituentchemical shifts in the case of both H and C nuclei, again with the exception of the carbons in themeta- position. Density Functional Theory (DFT)-predicted 1H and 13C chemical shifts correspondclosely with experimentally observed values, with some exceptions for C NMR data; however, thecorrelation is valid only for the aromatic moiety and cannot be extended to the heterocyclic ring ofthe chroman-4-one scaold.