Pyridine Based Chalcones: Synthesis and Evaluation of Antioxidant Activity of 1-Phenyl-3-(pyridin-2-yl)prop-2-en-1-one Derivatives

Chalcone: A Promising Bioactive Scaffold in Medicinal Chemistry

Chalcones are a class of privileged scaffolds with high medicinal significance due to the presence of an α,β-unsaturated ketone functionality. Numerous functional modifications of chalcones have been reported, along with their pharmacological behavior. The present review aims to summarize the structures from natural sources, synthesis methods, biological characteristics against infectious and non-infectious diseases, and uses of chalcones over the past decade, and their structure–activity relationship studies are detailed in depth. This critical review provides guidelines for the future design and synthesis of various chalcones. In addition, this could be highly supportive for medicinal chemists to develop more promising candidates for various infectious and non-infectious diseases.

Design, synthesis, characterization, and biological evaluation of nicotinoyl thioureas as antimicrobial and antioxidant agents

Addressed herein a series of thioureas starting from various amines and nicotinic acid have been synthesized. Notably, thiourea based scaffolds are increasingly employed in medicinal chemistry owing to their tunable physicochemical and structural properties. As well-known from the literature, the pyridine ring contains various biological properties, especially antimicrobial activity. Therefore, we performed the synthesis of biologically important thiourea derivatives containing pyridine ring. The structures of the synthesized compounds were characterized by ¹H NMR, ¹³C NMR and FT-IR. In the second part of the study, newly synthesized compounds were also tested in order to demonstrate their antimicrobial and antioxidant properties. All compounds exhibited moderate activity against all tested bacteria known to cause nosocomial infections, which have acquired resistance to many antibiotics, as compared to the standard antibiotics and also strong antioxidant properties. Therefore, they can be evaluated as possible seeds of agents in the treatment of bacterial infections and many health problems related to aging such as cancer, and neurodegenerative diseases.

Activation of Nrf2 signaling pathway by natural and synthetic chalcones: a therapeutic road map for oxidative stress

Introduction:Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a key role in diverse gene expressions responsible for protection against oxidative stress and xenobiotics. Chalcones with a common chemical scaffold of 1,3-diaryl-2- propen-1-one, are abundantly present in nature with a wide variety of pharmacological properties. This review will discuss the interactions of natural and synthetic chalcones with Nrf2 signaling.Areas covered:Chalcones are reportedly found to activate Nrf2 signaling pathway, expression of Nrf2-regulated antioxidant genes, induce cytoprotective proteins and upregulate multidrug resistance-associated proteins. Chalcones being soft electrophiles are less prone to hostile off-target effects and unlikely to induce carcinogenicity and mutagenicity. Furthermore, their low toxicity, structural diversity, feasibility in structural reorganization and the presence of α,β-unsaturated carbonyl group which makes them suitable drug candidates targeting Nrf2-dependent diseases.Expert opinion:Nrf2-Keap1 signaling pathway plays a central role in redox signaling. However, available therapeutic agents for Nrf2 activation have limited practical applications due to their associated risks, relatively low efficacy and bioavailability. The designing and fabrication of new chemical entities with chalcone scaffold-based Michael acceptor mechanism should be aimed as potential therapeutic Nrf2 activators to target oxidative stress and inflammation-mediated diseases such as atherosclerosis, Parkinson's disease and many more.

Pyridine azo disperse dye derivatives and their selenium nanoparticles (SeNPs): synthesis, fastness properties, and antimicrobial evaluations

Aim

Aiming to produce pyridine azo disperse dyes with good fastness properties and promising antimicrobial activity, a number of novel systems of polyfunctionalized pyridine azo dyes and their selenium nanoparticles (SeNPs) were synthesized.

Materials and methods

The synthesized products were formed by the reaction of diazotized aniline derivatives or diazotized amino antipyrene with any of dibenzoyl methane or benzoyl acetone and cyanoacetamide in boiling ethanolic sodium ethoxide. The structures of the newly synthesized compounds were elucidated by elemental analysis and spectral data. Moreover, (SeNPs) of the pyridine azo disperse dyes were characterized by Ultra-Violet -Visible spectrophotometry, dynamic light scattering , X-ray diffraction, and transmission electron microscope analysis. On the other hand, the synthesized dyes and its (SeNPs) were applied for disperse dyeing of nylon 66 and their fastness properties were measured, such as washing, rubbing, perspiration, and light fastness. In addition, the antimicrobial activities for all the synthesized compounds and for (SeNPs) prepared compounds (2bN, 2cN, 2fN, 2gN, 2hN) were evaluated.

Results

Compounds 2bN, 2c, 2cN, 2fN, 2gN, 2h, 2hN, and 2i were the most active compounds against all Gram-positive and Gram-negative bacterial species. While, compounds 2b, 2f, 2g, and 5b were the most active toward some of the bacterial strains (at least two from the selected four strains). Moreover, compounds 2bN, 2cN, 2fN, 2gN, 2h, 2hN showed higher activity toward the fungal strain. Also, the minimal inhibitory concentrations for all the most active compounds were determined.

Conclusion

Finally, all the (SeNPs) compounds revealed higher activity against bacterial and fungal strains than the other synthesized compounds.

A model compound for pyridinechalcone-based multistate systems. Ring opening-closure as the slowest kinetic step of the multistate

Amino-substituted pyridinechalcones configure multistate systems where a new type of flavylium derivative with potential biological activity are present.

Heterocyclization of polarized system: synthesis, antioxidant and anti-inflammatory 4-(pyridin-3-yl)-6-(thiophen-2-yl) pyrimidine-2-thiol derivatives

Background

Chalcones are intent in the daily diet as a favorable chemotherapeutic compound; on the other hand thiophene moiety is present in a large number of bioactive molecules having diverse biological efficiency.

Results

Our current goal is the synthesis of (E)-1-(pyridin-3-yl)-3-(thiophen-2-yl) prop-2-en-1-one 3 that^’s used as a starting compound to synthesize the novel pyrimidine-2-thiol, pyrazole, pyran derivatives. Chalcones 3 was prepared by condensation of 3-acetylpyridine with thiophene 2-carboxaldehyde which reacted with thiourea to obtain pyrimidinthiol derivative 4. Compound 4 was allowed to react with hydrazine hydrate to afford 2-hydrazinylpyrimidine derivative 5. Compound 5 was used as a key intermediate for a facile synthesis of the targets 6 and 7. In contrast, pyranone 8 was obtained by transformation of compound 5. Using as a precursor for the synthesis of new pyrazolo pyrimidine derivatives 9–10. The major incentive behind the preparation of these compounds was the immense biological activities associated to these heterocyclic derivatives.

Conclusions

The newly synthesized compounds (1–4) showed potent anti-inflammatory activities both in vitro and in vivo. They also exhibited promising antioxidant vitalities against α, α-diphenyl-β-picrylhydrazyl scavenging activity and lipid peroxidation. In conclusion, compound 1 showed a hopefully anti-inflammatory and antioxidant activities.