Proton and carbon NMR spectra of 4-substituted 1-acetylnaphthalenes

The proton and carbon spectra of ten 4-X-l-acetylnaphthalenes have been assigned. Shift correlations have been made with benzene substituent-induced chemical shifts (SCS, Lynch plots) and with dual substituent parameters (DSP) in the manner successfully done for many series of 1,4-disubstituted benzenes. The results obtained are compared with those for 4-X-acetophenones and 1-X-naphthalenes. The main conclusions are (i) the carbon para to the variable substituent X is more sensitive to change of substituent in the naphthalenes than in the benzenes, (ii) of the carbons ortho to the variable substituent X, that at C-3 is more sensitive and that at C-4a is less sensitive, to change of substituent in the naphthalenes than in the benzenes, (iii) the effect of the 4-substituents on the shift of H-8 in 1-acetylnaphthalenes is due mainly to changes in the carbonyl dipole affecting the diamagnetic screening of the proton.