. Can. J. Chem. 53,1958Chem. 53, (1975.The 13C n.m.r. spectra of anthracene and 11 methylated anthracenes have been examined. Analysis of the 'H spectra allowed unequivocal assignments for most of the protonated carbons by selective proton decoupling. Parameters describing the methyl substituent effects on the aryl carbon shieldings were defined and refined by regression analysis so that the 13C shieldings were predicted for 67 independent aryl positions in anthracenes without peri-methyls with a standard deviation of 0.12 p.p.m. Perimethyl-methyl interactions cause considerable deviations from the predicted substituent effects. The relationships of the.13C shieldings to charge densities calculated by the CNDO/2 method were briefly examined. Syntheses of 2,7,9-trimethyl-, 1,4,5,8-and 1,4,5,9-tetramethyl-, and 1,4,5,8,9-pentamethylanthracene are described. Chem. 53,1958Chem. 53, (1975 On a examine les spectres de resonance magnktique nucltaire du 13C de I'anthrackne et de 11 derives methyles de I'anthrackne. L'analyse des spectres 'H permet d'attribuer d'une facon non-6quivoque la resonance de la plupart des carbones protonts en faisant appel au decouplage selectif du proton. On a dkfini des paramktres dkrivant les effets d'un substituant mCthyle sur le blindage des carbones aromatiques. Ces paramktres ont kt6 affines par une analyse de rbression d'une facon telle que les blindages du 13C ont pu &re predits (avec une deviation standard de 0.12 p.p.m.) pour 67 positions aromatiques indipendantes dans des anthracknes sans groupement m6thyle en phi. Les interactions peri mkthyle-methyle causent des deviations considerable~ par rapport aux effets de substituants qui sont prbdits. On a examine brikvement les relations entre les blindages des 13C par rapport aux densites de charges calculees par la methode CNDO/2. On dkrit la synthkse du trimethyl-2,7,9, des tCtram6thyl-1, 4,5,8 et 1,4,5,9 et du pentamethyl-1,4,5,8,9 anthrackne. [Traduit par le journal] Introduction Since the pioneering studies of 13C spectra by Lauterbur and Burke and Lauterbur (1) in the early sixties, the utility of 13C shieldings for identification of hydrocarbons (2-4) and assessment of electronic structure (5-6) has been firmly established. There is great interest in the relationships of the chemical reactivities and electronic structures to carcinogenicities of several polynuclear aromatic hydrocarbons (7-9). Thus the potential of 13C n.m.r. studies to elicit information about the local electronic environments of