Novel azo dyes derived from 8-methyl-4-hydroxyl-2-quinolone: Synthesis, UV–vis studies and biological activity

Synthesis and pharmacological activities of azo dye derivatives incorporating heterocyclic scaffolds: a review

Nowadays, there is significant interest in the synthesis of heterocycle-incorporated azo dye derivatives as potential scaffolds in the pharmaceutical sector. The pharmaceutical or drug industries need a simplistic synthesis approach that can afford a wide range of azo dye derivatives. The incorporation of the heterocyclic moiety into the azo dye scaffold has improved the bioactive properties of the target derivatives. The various biological and pharmacological applications of drugs such as anti-fungal, anti-tuberculosis, anti-viral, anti-inflammatory, anti-cancer, anti-bacterial, DNA binding, and analgesic properties can be easily tuned by introducing heterocyclic moieties. To date, continuous efforts are being made in the search for more potent, new, and safe synthetic methodologies for azo dye derivatives. This review presents a brief discussion of the facile synthetic approaches and the relevance of the title compound and its derivatives towards various biological activities. Thus, the synthesis of azo dye derivatives incorporating heterocyclic scaffolds such as imidazole, pyrazole, thiazole, oxazolone, thiophene, pyrrole, benzothiazole and quinoline moieties and their pharmacological applications are discussed briefly.

Nowadays, there is significant interest in the synthesis of heterocycle-incorporated azo dye derivatives as potential scaffolds in the pharmaceutical sector.

Use of Nanocrystalline ZnO as an Efficient and Reusable Catalyst for a One-Pot, Three-Component Synthesis of 6-Chloro- and 5,7-Dichloro-4-Hydroxy-3-[Aryl (Piperidin-1-yl)Methyl]Quinolin-2(1H)-Ones in Water

A one-pot, green, efficient and facile procedure was applied for the preparation of a series of 4-hydroxy-3-[aryl(piperidin-1-yl)methyl] quinolin-2(1 H)-ones via the reaction of 6-chloro-4- hydroxyquinoline-2(1 H)-one 1 and/or 5,7-dichloro-4-hydroxyquinoline-2(1 H)-one 2, piperidine and aromatic aldehydes in water in the presence of nanocrystalline ZnO under reflux conditions. The desired products were obtained in satisfactory yields. The nanocrystalline ZnO can be separated and reused at least up to three times with almost the same catalytic activity.

Efficient Synthesis of 4-Hydroxybenzo[h]Quinoline-2(1H)-One and Some Derivatives

3-(Naphlhyl-1-amino)-3-oxopropanoic acid and N,N′-di(naphthyl-1-yl)malonamide were synthesised by the reaction of 1-naphthylamine with diethyl malonate under reflux. These two compounds were then separately cyclised to 4-hydroxybenzo[ h]quinolin-2-(1 H)-one in two different reactions in polyphosphoric acid. A series of esters and ethers of the 4-hydroxy group and some 3-substituted derivatives were prepared. The structures of the compounds were confirmed by infra-red NMR spectroscopy and elemental analysis.

Computational and spectroscopic data correlation study of N,N'-bisarylmalonamides (Part II)

To complement a previous UV study, we present a quantitative evaluation of substituent effects on spectroscopic data ((1)H and (13)C NMR chemical shifts as well as FT-IR absorption frequency) applied to N,N'-bisarylmalonamides, using simple and extended Hammett equations as well as the Swain-Lupton equation. Furthermore, the DFT CAM-B3LYP/6-311+G(d,p) method was applied to study the impact of different solvents on the geometry of the molecules and their spectral data. Additionally, experimental data are correlated with theoretical results; excellent linear dependence was obtained. The overall results presented in this paper show that N,N'-bisarylmalonamides are prominent candidates for model molecules.

Spectroscopic studies of keto–enol tautomeric equilibrium of azo dyes

Keto–enol tautomeric equilibrium of an azo dye is shifted to the keto form as the solvent polarity is increased.

Spectroscopic and quantum mechanical investigation of N,N'-bisarylmalonamides: solvent and structural effects

The UV absorption spectra of ten N,N'-bisarylmalonamides have been recorded in the range 200-400 nm in a set of selected solvents. The solute-solvent interactions have been analyzed on the basis of the linear solvation energy relationship (LSER) concept proposed by Kamlet and Taft. The effects of substituents on the absorption spectra have been interpreted by correlating absorption frequencies with Hammett substituent constants. Furthermore, the experimental findings have been interpreted using the DFT CAM-B3LYP/6-311+G(d,p) method. Electronic energies have been calculated using the same method in combination with the implicit solvation model (conductor-like polarizable continuum model, CPCM) as well as with the explicit addition of two molecules of solvent.