Excited State Proton Transfers in Hybrid Compound Based on Indoline Spiropyran of the Coumarin Type and Azomethinocoumarin in the Presence of Metal Ions

Spectral-luminescence properties of a hybrid compound containing a coumarin-type spiropyran and an azomethinocoumarin fragment in toluene-acetonitrile solution in the presence of Li+, Ca2+, Zn2+ and Mg2+ ions are reported. Two excited state proton transfers can occur in the hybrid compound—the transfer of a proton from the OH group of the 7-hydroxy coumarin tautomer to the N atom of the C=N bond of the azomethine fragment leading to green ESIPT fluorescence with a maximum at 540 nm and from the OH group of the 7-hydroxy coumarin tautomer to the carbonyl group of the pyrone chromophore, which leads to the formation of the 2-hydroxyl-tautomer T of coumarin with blue fluorescence with a maximum at 475 nm. Dependence of these excited state proton transfers on the metal nature and irradiation with an external UV source is discussed.

Design, synthesis and biological evaluation of substituted pyrazoles endowed with brominated 4-methyl 7-hydroxy coumarin as new scaffolds against Alzheimer’s disease

Background The study aimed to design, synthesize and evaluate various brominated derivatives of 7-hydroxy coumarin as a new scaffold against Alzheimer’s disease by in vivo and in vitro models. A group of three novel pyrazoles endowed with brominated 7-hydroxy 4-methyl coumarin derivatives were designed. Among the designed compounds, a single entity (D1) was selected based on the docking score, which could be considered mainly for the treatment of Alzheimer’s disease. Three novel pyrazoles endowed with brominated 7-hydroxy 4-methyl coumarin derivatives were designed and docking studies of these compounds were carried out using Argus lab4.0.1 version. According to the docking score, a single entity of compound (D1) was selected for further study. The structure of the compound (D1) was explored by spectral analysis. The anti-Alzheimer’s activity was evaluated by in vivo and in vitro methods. All results were compared statistically by one-way ANOVA using GraphPad Prism. Results Molecular docking studies revealed that the compound D1 was able to bind simultaneously to the amino acid and in the active sites of the acetylcholine esterase enzyme. In acetylcholine esterase inhibition assay, the compound shows a significant increase in acetylcholine esterase level. The MAO inhibitory activities were in the nanomole range (human MAO-A IC50 = 3.9, human MAO-B IC 50 = 4.4). DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay showed that the compound shows a promising antioxidant property. In the evaluation of learning and memory of compound D1 using elevated plus maze, the compound D1-pretreated group showed a significant increase in memory and learning when compared with donepezil. Conclusions Among the designed series of pyrazole endowed with brominated 7-hydroxyl 4-methyl coumarin derivatives, compound D1 showed good antioxidant property and acetylcholine esterase and MAO inhibitory activity; based on this property, the synthesized compound D1 can be considered a new scaffold on Alzheimer’s disease.

One-Pot Three-Component Synthesis of 2-Amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbonitrile Derivatives Catalyzed by Cobalt Doped Iron (III) Tartrate Complex

An environmentally friendly one-pot three-component strategy synthesizing a series of 2-Amino-5-oxo-4,5-dihydropyrano[3,2-c]chromene-3-carbonitrile derivatives has been successfully performed in water. The products were obtained through conventional and microwave irradiation, which involving aldehyde, malononitrile, and 4-hydroxy coumarin, resulting in a green synthetic protocol with a high atom economy. The reaction was catalyzed by a water-soluble and reusable catalyst, i.e., cobalt doped iron (III) tartrate complex. The catalyst was recovered and efficiently reused.

Anti-tumor agents: Design, Synthesis, and Biological study of N-Substituted-7-hydroxy-1-azacoumarin-3-carboxamide derivatives as potent cytotoxic agents

Synthesis of ethyl 7-hydroxy-1-azacoumarin-3-carboxylate (3) was developed using ethyl-7-hydroxy coumarin-3-carboxylate and ammonium solution as the key synthons. Condensation of ethyl 7-hydroxy-1-azacoumarin-3-carboxylate with ammonium acetate and aniline to give N-substituted-7-hydroxy-1-azacoumarin-3-carboxamides (7-Hydroxy -1-azacoumarin-3-carboxamide (4) and N-phenyl 7-Hydroxy-1-azacoumarin-3-carboxamide (5)). Bromo derivative (N-phenyl 6, 8-dibromo-7-hydroxy-1-azacoumarin-3-carboxamide (6)) was obtained from halogenation of compound N-phenyl 7-Hydroxy-1-azacoumarin-3-carboxamide (5) with bromine in glacial acetic acid. N-phenyl-2,5-diacetoxy-6, 8-disubstituted-Quinoline-3-carboxamides (N-phenyl 2,7-diacetoxy-Quinoline-3-carboxamide (7) and N-phenyl 2,7-diacetoxy-6,8-dibromo-Quinoline-3-carboxamide (8)) were prepared via the acetylation of compounds 5 and 6 with acetic anhydride. Five compounds 4–8 were evaluated in vitro against more than one human tumor cell lines. Among the selected compounds, 6 showed the best in vitro cytotoxicity against the human cancer cell line; MCF-7 (with IC50 = 10.12 μM). In addition, cell cycle analysis of compound 6 demonstrated cell cycle arrest at G2/M phase and Pre-G1 apoptosis.

Protective Effects of 3-benzoyl-7-hydroxy Coumarin on Liver of Adult Rat Exposed to Aluminium Chloride

In this study, the effects of 3-benzoyl-7-hydroxy coumarin molecule on mineral and antioxidant enzymes were investigated in rat liver exposed to oxidative stress with aluminium chloride (AlCl3). Adult male Wistar albino rats were divided into four groups as Control, Coumarin, AlCl3, and Coumarin + AlCl3. Coumarin at the dose of 10 mg/kg and AlCl3 at the dose of 8.3 mg/kg were administered for 30 days every other day. In AlCl3 group, malondialdehyde (MDA), iron (Fe), aluminium (Al) and copper (Cu) levels increased compared to the control group, while glutathione (GSH) level, glutathione S-transferase (GST), and carboxylesterase (Ces) enzyme activity levels decreased. In Coumarin + AlCl3 group, MDA, Fe, Al and Cu levels decreased with the effect of coumarin compared to AlCl3 group, while GSH level, and GST enzyme activity levels increased. According to our results, AlCl3 generates oxidative stress in rat livers, and we believe that 3-benzoyl-7-hydroxy coumarin has an ameliorative effect on antioxidant enzyme system, Al, Fe and Cu levels.