Synthesis and antimicrobial activity of coumarin pyrazole pyrimidine 2,4,6(1H,3H,5H)triones and thioxopyrimidine4,6(1H,5H)diones

An Efficient and Versatile Deep Eutectic Solvent-Mediated Green Method for the Synthesis of Functionalized Coumarins

Herein, we report a green and efficient synthetic route for the construction of diverse functionalized coumarins in good-to-excellent yields (60-98%) via the Pechmann condensation. The optimized synthetic route involves a biodegradable, reusable, and inexpensive deep eutectic solvent (DES) of choline chloride and l-(+)-tartaric acid in a ratio of 1:2 at 110 °C. Interestingly, phloroglucinol and ethyl acetoacetate, upon reaction, furnished the functionalized coumarin (20) in 98% yield within 10 min. On the other front, the same DES at relatively lower reaction temperature (90 °C) was found to provide the bis-coumarins in decent yields (81-97%) within 20-45 min. Moreover, this particular method was found to be quite effective for large-scale coumarin synthesis without noteworthy reduction in the yields of the desired products. Noticeably, in this versatile approach, the DES plays a dual role as solvent as well as catalyst, and it was effectively recycled and reused four times with no significant drop-down in the yield of the product.

Design, synthesis and biological evaluation of novel deoxyvasicinone-indole as multi-target agents for Alzheimer's disease

In this study, a series of multifunctional hybrids (6a-6l) against Alzheimer's disease were designed and obtained by conjugating the pharmacophores of deoxyvasicinone and indole. These analogs of deoxyvasicinone-indole were evaluated as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), and as inhibitors of amyloid aggregation (Aβ_1-42) for treatment of Alzheimer's disease (AD). Subsequently, AChE induced Aβ aggregation inhibition test was also performed for selected compounds. Biological activity results demonstrated that compound 6b was the most potent and balanced dual ChEs inhibitor with IC₅₀ values 0.12 µM and 0.15 µM for eeAChE and eqBuChE, respectively. Kinetic analysis and docking study indicated that compound 6b was a mixed-type inhibitor for both AChE and BuChE. Compound 6b also found to be the best inhibitors of self-induced Aβ_1-42 aggregation with IC₅₀ values of 1.21 µM. Compound 6b also afforded excellent inhibition of AChE-induced Aβ_1-42 aggregation by 81.1%. Overall, these results indicate that 6b may be considered as lead compound for the development of highly effective anti-AD drugs.

I2/DMSO-catalyzed one-pot approach for the synthesis of 1,3,4-selenadiazoles

A three-component cascade reaction for the synthesis of 1,3,4-selenadiazoles and their derivatives from arylaldehydes, hydrazine, and elemental selenium by using molecular iodine is reported. This strategy is operationally simple, well-suited to a wide range of functional groups, and provides the desired products in moderate to excellent yields. The proposed mechanism predicts that the reaction tolerated a radical process.

Hybrid Molecules Development: A Versatile Landscape for the Control of Antifungal Drug Resistance: A Review

Hybrid molecule approach of drug design has become popular due to advantages such as delayed resistance, reduced toxicity, ease of treatment of co-infection and lower cost of preclinical evaluation. Antifungal drugs currently available for the treatment of fungal diseases suffer a major side effect of drug resistance. Hybrid drugs development is one of the approaches that has been employed to control microbial resistance. Their antifungal activity is influenced by their design. This review is focused on hybrid molecules exhibiting antifungal properties to guide scientists in search of more efficient drugs for the treatment of fungal diseases.

Co3O4/NiO@GQD@SO3H nanocomposite as a superior catalyst for the synthesis of chromenpyrimidines

A three-component reaction involving aromatic aldehydes, 6-amino-1,3-dimethyluracil and 4-hydroxycoumarin was achieved in the presence of the Co₃O₄/NiO@GQD@SO₃H nanocomposite as a highly effective heterogeneous catalyst to produce chromenpyrimidines. The catalyst was characterized via FT-IR, SEM, XRD, EDS, TGA, BET and VSM. This new catalyst was demonstrated to be highly effective in the preparation of chromenpyrimidines. Atom economy, low catalyst loading, reusable catalyst, applicability to a wide range of substrates and high product yields are some of the important features of this protocol.

A flexible and highly efficient protocol for the synthesis of chromenpyrimidines using the Co₃O₄/NiO@GQD@SO₃H nanocomposite has been developed.

Sulfonation of carbonized xylan-type hemicellulose: a renewable and effective biomass-based biocatalyst for the synthesis of O- and N-heterocycles

The application of biomass-based carbonaceous solid acids in catalysis is attracting increasing attention in the field of chemistry.

Fe(III)-montmorillonite catalysed one pot synthesis of 5-substituted dihydropyrimidine derivatives as potent antimicrobial agents

Objectives

This paper aims to describe the synthesis of a series of novel 5-substituted dihydropyrimidine derivatives using Fe-(III)-montmorillonite as an efficient and reusable catalyst.

Methods

The structures of the synthesized compounds were confirmed by Fourier transform-infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) and mass spectroscopy methods. The title compounds were screened for antimicrobial activity, and molecular docking studies were conducted.

Results

The results revealed that the catalyst significantly enhanced the reaction time and product yield. The antimicrobial activity results indicated that compounds 4c, 4e and 4k exhibited promising antimicrobial activity against the tested microorganisms.

Conclusion

The catalyst can be recycled at least two to three times without a noticeable decrease in its catalytic activity. The synthesized compounds displayed promising antimicrobial activity.

Design and Microwave Assisted Synthesis of Coumarin Derivatives as PDE Inhibitors

Coumarins appended to benzimidazole through pyrazole are designed and synthesized using microwave irradiation. These compounds were analyzed for phosphodiesterase (PDE) inhibition indirectly by motility pattern in human spermatozoa. Some of the synthesized compounds, namely, 5d, 5e, 5f, 5g, 5h, and 5k, have exhibited potent inhibitory activity on PDE.

Recent advances and perspectives in the synthesis of bioactive coumarins

The impressive pharmacological properties shown by a number of coumarins have led to extraordinarily large emphasis being placed on the design of more efficient and greener synthetic procedures to produce them.

2,5-Disubstituted 1,3,4-oxadiazole derivatives of chromeno[4,3-b]pyridine: synthesis and study of antimicrobial potency

A convenient synthesis of 1,3,4-oxadiazole containing derivatives of chromeno[4,3-

3-(1-Phenyl-4-((2-(4-arylthiazol-2-yl)hydrazono)methyl)-1H-pyrazol-3-yl)-2H-chromen-2-ones: one-pot three component condensation, in vitro antimicrobial, antioxidant and molecular docking studies

A series of novel pyrazolyl coumarin bearing 2,4-disubstituted thiazole derivatives (5a-l) have been synthesized efficientlyviathree-component one-pot manner by Hantzsch condensation.

Cholinium ionic liquids as cheap and reusable catalysts for the synthesis of coumarins via Pechmann reaction under solvent-free conditions

Ionic liquid [N₁₁₂OH][HSO₄] was found to be an efficient and reusable catalyst for Pechmann reaction under solvent-free conditions. UV-vis studies suggested that the high catalytic performance of this catalyst was mainly due to its ability to increase the content of keto tautomer of ethyl acetoacetate.