Syntheses of 10-Methyl-9-phenyl-9, 10-dihydroacridines and Their Visible Spectra in Acetic Acid

Abstract

10-Methyl-9-(p-substituted phenyl)-9, 10-dihydroacridines were synthesized by the condensation reaction of 10-methylacridones with substituted benzenes: with anilines in POCl₃, with Grignard reagents or with phenyllithium.
The visible spectra of the synthesized 9, 10-dihydroacridines were observed in acetic acid to investigate the effect of substituents X and Y on the 9, 10-dihydroacridine moiety and the pendant phenyl group, respectively. Their excitation energy were calculated by the PPPMO method. A little shift. of λmax was observed for the compounds with a relatively low electrondonating substituent Y, 'while a remarkable shift of λmax observed for the compounds with a strong electron-doniting ubstituent Y=NMe₂. The calculated π elecitron density changes by the PPPMO method may support an inteamolecular charge-tiansfer charactor of the first absorption band in which electron densities transfered from ring C (with substituent Y=H, OCH₃, and NME₂) to acridine rings A, B, and D (with no substituent); and from ring A (with substituent X=NMe₂) to the rings B, C and D (with substituent and OCH₃).