AbstractsChemistry

In order to obtain assessment of the relative substituent effects of the acenaphthene bridge, the 1-methyl, and the 1,8-dimethyl groups in naphthalene derivatives, the following series of acids has been prepared:- 1-methyl-2-maphthoic, 4-methyl-1-naphthoic, 1,8-dimethyl-2-naphthoic, 4,5-dimethyl-2-naphthoic, 4,5-dimethyl-1-naphthoic, and 3-, 4-, and 5-acenaphthoic acids. The dissociation constants of these acids, as well as those of 1-naphthoic, 2-naphthoic and 5-methyl-1-naphthoic acids, were determined in 20% (w/w) dioxin-water solutions at 25°, by an ultraviolet spectrophotometric method. In addition the ultraviolet spectra of those acids having the carboxyl group attached to the β-position of the naphthalene ring were determined over the range 3000-3600 Å, in the same solvent. 1-Methyl-2-dimethylaminonaphthalene and 3-dimethyl-aminoceneaphthene were prepared and their ultraviolet spectre, together with that of 2-dimethylaminonaphthalene, were determined with that of 2-dimethylaminonaphthalene, were determined over the range 2400-3600Å using hexane as the solvent. From the results obtained, conclusions have been drawn concerning the relative electron-releasing abilities and steric requirements of the three substituent groups.