1990 Volume 63 Issue 8 Pages 463-469
Syntheses of 3-Mono- and 3,3-diarylphthalides with various substituents were carried out. The effects of the substituents on the visible spectra in acetic acid and the chromopheric systems were investigated on the basis of the PPP-MO calculation.
3-Monoarylphthalides were prepared by the condensation of 5-dimethylamino-2-formylbenzoic acid with heterocycles or m-dimethylaminobenzoic acid with benzaldehydes. The monoaryl-phthalides were then oxidized to 2-benzoyl-5-dimethylaminobenzoic acids, which were subjected to a reaction with heterocycles (R-H) in acetic anhydride to give 3,3-diarylphthalides. Two absorption bands were observed in each visible spectrum of a 3,3-diarylphthalide in 95% acetic acid. The two bands were assigned as x- and y-bands of tri-phenylmethane chromophores by the PPP-MO calculation.