Carbon-13 N.M.R. Studies of 1,4-Naphthoquinones and 9,10-Anthraquinones

Abstract

Carbon-¹³ n.m.r, spectra of a range of hydroxy-, methyl-, methoxy- and halo-substituted 1,4-naphthoquinones and methyl-substituted 9,10-anthraquinones have been measured and assignments made on the basis of ¹³C-¹H and ¹³C-¹⁹F coupling constants, selective proton-decoupling and deuterium-labelling experiments. The quinonoid carbon (C2 and C3) resonances in juglone (4) and juglone methyl ether (7) have been assigned unequivocally from the spectra of deuterated derivatives. Substituent effects are discussed in comparison with previously published data.