Synthesis of some 1,8-dioxoacridine carboxylic acid derivatives and the determination of their ionization constants in ethanol–water mixtures

• Published in: Journal of molecular structure 2015-03, Vol.1083, p.252-259
• Main Authors: Saygılı, Rukiye, Ulus, Ramazan, Yeşildağ, İbrahim, Kübra İnal, E., Kaya, Muharrem, Murat Kalfa, O., Zeybek, Bülent
• Format: Article
• Language: English
• Subjects: 1,8-Dioxoacridine carboxylic acid derivatives; Benzaldehyde; Carboxylic acids; Composition effects; Constants; Derivatives; Ethanol–water mixtures; Ethyl alcohol; Ionization; Ionization constants; Mathematical analysis; Potentiometric titration; Solvent effect; Titration
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2014.12.002

[Display omitted] •Four new compounds of 1,8-dioxoacridine carboxylic acid derivatives were synthesized.•The pKa values of these compounds were determined by potentiometric titration method.•This procedure was performed in ethanol–water mixtures of 50%, 60%, 70% ethanol (v/v).•The effects of structure and solvent on pKa values of these compounds were discussed. Four novel compounds of 1,8-dioxoacridine carboxylic acid derivatives (4-(3,3,6,6-tetramethyl-1,8-dioxo-9-phenyl-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-cyanophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(4-hydroxyphenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid, 4-(9-(2,4-dichlorophenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8-octahydroacridin-10(9H)-yl)benzoic acid) were prepared by the reaction of the 4-substitute benzaldehyde (hydrogen, hydroxyl, cyano, and 2,4-dichloro), 4-aminobenzoic acid, and 5,5-dimethylcyclohexane-1,3-dione in the presence of p-dodecylbenzenesulfonic acid. They were characterized by using FT-IR, 1H-NMR, 13C-NMR, GC–MS spectroscopic techniques. The stoichiometric ionization constants of these compounds were determined in ethanol–water mixtures of 50%, 60% and 70% ethanol (v/v) by potentiometric titration method and the ionization constants were calculated with three different ways. The effects of solvent composition and substituent groups on ionization constants of 1,8-dioxoacridine carboxylic acids were also discussed.