Collect. Czech. Chem. Commun. 1981, 46, 1775-1787

13C NMR study of substituted quinone methides. 2- and 2,6-substituted fuchsones

Antonín Lyčkaa, Dobroslav Šnobla, Bohumír Koutekb, Libuše Pavlíčkováb and Milan Součekb

a Research Institute of Organic Syntheses, 532 18 Pardubice-Rybitví
b Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


Carbon-13 chemical shifts and 1J(CH) coupling constants for 11 fuchsones of the types I and II in deuteriochloroform are reported. The assignments are based on an analysis of proton coupled and proton decoupled spectra and on the analogy to chemical shifts of some structuraly related compounds. Satisfactory Swain-Lupton F and R correlations which were found for most of 13C chemical shifts afforded values for percent resonance contributions to transmission of substituent effects as follows, C(1), 19%; C(3), 71%; C(7), 43%. Some alternative correlations for other similar systems e.g. quinones and tropones are also given.