¹H, ¹³C and ¹⁷O NMR spectral study of 4,1‐disubstituted naphthalenes

Abstract

Abstract The 1 H, 13 C and 17 O NMR spectra of several 4,1‐disubstituted naphthalenes, viz. 4‐substituted 1‐ acetylnaphthalenes (series 1), 4‐substituted 1‐nitronaphthalenes (series 2), 4‐substituted 1‐methoxynaphthalenes (series 3) and 4‐substituted 1‐naphthyl methyl sulphides (series 4), were measured. The 17 O and 13 C chemical shifts of these 4,1‐disubstituted naphthalenes were compared with those of the corresponding 4,1‐disubstituted benzenes and analysed using the dual substituted parameter (DSP) equation. It is concluded that in series 1, 2 and 4 the substituent effects from the 4‐substituent to the C‐1 carbon and the side‐chain atoms are transmitted more effectively than those in the corresponding 4,1‐disubstituted benzenes, whereas the transmission in series 3 is almost equal to that in the analogous benzene series, viz. 4‐substituted anisoles. The reverse substituent effects displayed by the H‐8 chemical shifts of series 1 and 2 and the existence of linear relationships between the chemical shifts of H‐8 and the 17 O chemical shifts of the oxygen of both the acetyl and nitro groups in series 1 and 2, respectively, are ascribed mainly to changes in the electron densities on the oxygen of the carbonyl and nitro groups affecting the diamagnetic screening of the proton.