A novel and easy two-step, microwave-assisted method for the synthesis of halophenyl pyrrolo[2,3-b]quinoxalines via their pyrrolo precursors. Evaluation of their bioactivity

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

Substituted 4-acetyl-3-hydroxy-3-pyrroline-2-ones have been prepared via three-component reactions and the tautomerism of these 3-pyrroline-2-ones is due to the slight difference of energy, and the significantly large rate constant of transformation between two tautomers. 1,4,5-Trisubstituted pyrrolidine-2,3-dione derivatives were prepared from the above mentioned 2-pyrrolidinone derivatives and aliphatic amines, which exist in enamine form and are stabilized by an intramolecular hydrogen bond. A possible reaction mechanism between 3-pyrroline-2-one and aliphatic amine (CH3NH2) was proposed based on computational results and the main product is formed favorably following the PES via the lowest ΔG # pathway in both the gas-phase and an ethanol solvent model. DFT calculations showed that kinetic selectivity is more significant than thermodynamic selectivity for forming main products.

Synthesis and evaluation of the antioxidant activity of 3-pyrroline-2-ones: experimental and theoretical insights

The heterocyclic γ-lactam ring 2-pyrrolidinone has four carbon atoms and one nitrogen atom. Among the group of derivatives of 2-pyrrolidinones, 1,5-dihydro-2H-pyrrol-2-ones, also known as 3-pyrroline-2-ones, play a significant structural role in a variety of bioactive natural compounds. In this study, three-component reactions were used to successfully synthesize six polysubstituted 3-hydroxy-3-pyrroline-2-one derivatives. The antioxidant activity of the compounds was tested by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, identifying 4-ethoxycarbonyl-3-hydroxy-5-(4-methylphenyl)-1-phenyl-3-pyrroline-2-one (4b) as the most promising radical scavenger. Quantum chemistry calculations of the thermodynamics and kinetics of the radical scavenging activity also suggest that 4b is an effective HO˙ radical scavenger, with k_overall values of 2.05 × 10⁹ and 1.54 × 10¹⁰ M⁻¹ s⁻¹ in pentyl ethanoate and water, respectively. On the other hand, 4b could not scavenge hydroperoxyl radicals in either media. The ability of 4b to scavenge hydroxyl radicals in polar and non-polar environments is comparable to that of conventional antioxidants such as melatonin, gallic acid, indole-3-carbinol, ramalin, or Trolox. Thus 4b may be classed as a promising HO˙ radical scavenger in the physiological environment.

Derivatives of 3-hydroxy-3-pyrroline-2-one were effectively synthesized via multicomponent reactions and exhibited potential HO˙ radical scavenging activity.

Quinoxaline Derivatives as Antiviral Agents: A Systematic Review

Background: In recent decades, several viruses have jumped from animals to humans, triggering sizable outbreaks. The current unprecedent outbreak SARS-COV-2 is prompting a search for new cost-effective therapies to combat this deadly pathogen. Suitably functionalized polysubstituted quinoxalines show very interesting biological properties (antiviral, anticancer, and antileishmanial), ensuring them a bright future in medicinal chemistry. Objectives: Focusing on the promising development of new quinoxaline derivatives as antiviral drugs, this review forms part of our program on the anti-infectious activity of quinoxaline derivatives. Methods: Study compiles and discusses recently published studies concerning the therapeutic potential of the antiviral activity of quinoxaline derivatives, covering the literature between 2010 and 2020. Results: A final total of 20 studies included in this review. Conclusions: This review points to a growing interest in the development of compounds bearing a quinoxaline moiety for antiviral treatment. This promising moiety with different molecular targets warrants further investigation, which may well yield even more encouraging results regarding this scaffold.

Multicomponent Reaction of Aldehydes, Amines and Oxalacetate Analogues Leading to Biologically Attractive Pyrrole Derivatives

Pyrrole is a very important pharmacophoric moiety. It has been widely incorporated into the skeleton of antitumor, anti-inflammatory, antibacterial, antioxidant and antifungal active substances. Access to this key heterocycle by diverse routes is particularly attractive in terms of chemistry, and also from the environmental point of view. The present minireview summarizes the reported methods for the preparation of highly substituted pyrrole derivatives based on the one-pot multicomponent reaction of aldehydes, primary amines, and oxalacetate analogues as well as their biology.

One-pot synthesis of biologically active 1,2,3-trisubstituted pyrrolo[2,3-b]quinoxalines through a palladium-catalyzed reaction with internal alkyne moieties

Synthesis of 2,3-disubstituted 1-alkylpyrrolo[2,3-b]quinoxalines was accomplished through the reaction of 3-chloroquinoxalin-2-amines with internal alkynes in the presence of Pd(OAc)[Formula: see text], NaOAc, and KOtBu in DMSO. This method afforded desired pyrrolo[2,3-b]quinoxalines in 65-92% reaction yields. The minimum inhibition concentration and minimum bactericidal concentration determinations against Micrococcus luteus and Pseudomonas aeruginosa revealed that some of the synthesized compounds showed the same values compared to tetracycline. These compounds could be used in the future research for the development of new antibiotics.