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A few computational studies indicated that some inhibitors of viral RNA–polymerase such as favipiravir could also inhibit cysteine proteases. The potential dual action of favipiravir as an inhibitor for both RNA–polymerase and proteases promises enhanced therapeutic efficacy of the drug against coronaviruses. To shed more light on this phenomenon, in view of the chemical structure of favipiravir and the recent advances in this field, six novel derivatives of 3-methyl quinoxaline were synthesized. In silico methods confirmed the abilities of these compounds to occupy the active-site clefts of both 3CLpro and PLpro with favorable interactions, while the ADMET evaluations predicted low toxicity and high bioavailability for them. Then, due to the high similarities between PLpro and papain, the inhibitory impacts of favipiravir and the synthesized quinoxalines on the kinetics of papain were thoroughly investigated. The outcome revealed that the potential dual-action of favipiravir-like compounds is a possibility that should be taken into account in designing more effective and safe drugs against coronavirus. [ABSTRACT FROM AUTHOR]

Halogenation of Y‐series small‐molecule acceptors (Y‐SMAs) is identified as an effective strategy to optimize photoelectric properties for achieving improved power‐conversion‐efficiencies (PCEs) in binary organic solar cells (OSCs). However, the effect of different halogenation in the 2D‐structured large π‐fused core of guest Y‐SMAs on ternary OSCs has not yet been systematically studied. Herein, four 2D‐conjugated Y‐SMAs (X‐QTP‐4F, including halogen‐free H‐QTP‐4F, chlorinated Cl‐QTP‐4F, brominated Br‐QTP‐4F, and iodinated I‐QTP‐4F) by attaching different halogens into 2D‐conjugation extended dibenzo[f,h]quinoxaline core are developed. Among these X‐QTP‐4F, Cl‐QTP‐4F has a higher absorption coefficient, optimized molecular crystallinity and packing, suitable cascade energy levels, and complementary absorption with PM6:L8‐BO host. Moreover, among ternary PM6:L8‐BO:X‐QTP‐4F blends, PM6:L8‐BO:Cl‐QTP‐4F obtains a more uniform and size‐suitable fibrillary network morphology, improved molecular crystallinity and packing, as well as optimized vertical phase distribution, thus boosting charge generation, transport, extraction, and suppressing energy loss of OSCs. Consequently, the PM6:L8‐BO:Cl‐QTP‐4F‐based OSCs achieve a 19.0% efficiency, which is among the state‐of‐the‐art OSCs based on 2D‐conjugated Y‐SMAs and superior to these devices based on PM6:L8‐BO host (17.70%) and with guests of H‐QTP‐4F (18.23%), Br‐QTP‐4F (18.39%), and I‐QTP‐4F (17.62%). The work indicates that halogenation in 2D‐structured dibenzo[f,h]quinoxaline core of Y‐SMAs guests is a promising strategy to gain efficient ternary OSCs. [ABSTRACT FROM AUTHOR]

Demonstrated here is an external photo‐sensitizer‐free (auto‐sensitized) singlet oxygen‐enabled solvent‐dependent tertiary hydroxylation and aryl‐alkyl spiro‐etherification of C3‐maleimidated quinoxalines. Such "reagent‐less" photo‐oxygenation at Csp3‐H and etherification involving Csp3‐H/Csp2‐H are unparalleled. Possibly, the highly π‐conjugated N‐H tautomer allows the substrate to get excited by irradiation, and subsequently, it attains the triplet state via ISC. This excited triplet‐state sensitized molecule then transfers its energy to a triplet‐state oxygen (3O2) generating reactive singlet oxygen (1O2) for hydroxylation and spirocyclization depending on the solvent used. In HFIP, the generated alkoxy radical accepts a proton via HAT giving hydroxylated product. In contrast, in an aprotic PhCl it underwent a radical addition at the ortho‐position of the C2 aryl to provide spiro‐ether. An unprecedented orthogonal spiro‐etherification was observed via the displacement of o‐substitutents for ortho (−OEt, −OMe, −F, −Cl, −Br) substituted substrates. The order of ipso substitution follows the trend −OMe>−OEt>−F>−H>−Cl>−Br. Both these oxygenation reactions can be carried out with nearly equal ease using direct sunlight without the requirement of any elaborate reaction setup. Demonstration of large‐scale synthesis and a few interesting transformations have also been realized. Furthermore, several insightful control experiments and quantum chemical computations were performed to unravel the mechanism. [ABSTRACT FROM AUTHOR]

The nano size Cu-Zn ferrite particles substituted to Mg2+ and La3+ having general chemical formula MgxCu0.3Zn0.7-xLayFe2-yO4 (x = 0.1, 0.2, 0.3, 0.4, 0.5; and y = 0.0, 0.025, 0.050, 0.075, 0.10) prepared through sol-gel method. The prepared mixed metal oxide nanoparticles were characterized employing techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) analyses. The prepared MgxCu0.3Zn0.7-xLayFe2-yO4 magnetic nanoparticles were used as a efficient, recoverable and heterogeneous catalyst for the one-pot synthesis of quinoxalines 3(a–g) and 1,5-benzodiazepines 5(a–h) under mild reaction conditions in good yields. The recyclability of catalyst was tested for five times without significant decrease in the catalytic activity. Catalyst has been used for the synthesis of different derivatives of quinoxalines in short time (20 to 30 min) with 90 -97% yield. Also, different derivatives of 1,5-benzodiazepines have been synthesized in short time (15 to 30 min) with 89 -98% yield using the catalyst. [ABSTRACT FROM AUTHOR]

The rising instances of drug resistance in Mycobacterium tuberculosis strains pose a significant global health challenge. Conventional tuberculosis (TB) treatments, which typically involve multiple antibiotics, face hurdles like drug resistance, reduced effectiveness, and heightened toxicity. Consequently, there is a pressing need for innovative anti-TB agents with new modes of action. Decaprenyl-phosphoryl-β-d-ribose 2′-epimerase 1(DprE1), a crucial enzyme in Mycobacterium tuberculosis, plays a vital role in cell wall biosynthesis – a critical aspect for the bacterium’s survival. Building on the success of diarylquinolines like bedaquiline, targeting DprE1 presents a promising avenue for developing anti-TB drugs, especially against drug-resistant strains. Our research focused on discovering novel DprE1 inhibitors using a ligand-based drug design strategy, starting with the established non-covalent inhibitor Ty38c. We assembled a library of 16 molecules, modifying them based on factors like drug-like properties, chemical accessibility, and synthetic feasibility. Molecular docking analyses of this library identified three molecules with binding affinities comparable to Ty38c. Among these, KS_QD_05 and KS_QD_04 are promising candidates, which were further validated through molecular dynamics simulation studies where root-mean-square deviation (RMSD) values of all three complexes reached a plateau, measuring around 0.3 nm, indicating that the apoprotein and all complexes stabilized during the simulation. The ligands KS_QD_04 and KS_QD_05 displayed significantly stable deviation. KS_QD_05 reached about 0.1 nm equilibrium value. However, the ligand KS_QD_04 reached an RMSD value of 0.17 nm and showed distress at 70 nm. KS_QD_04 and KS_QD_05 showed an average value of 1-3 H-bond interaction and regarding the RMSF values, both the compounds showed fluctuations less than 0.5 nm in the case of Mtb. DprE1 enzyme. This indicates the potential of both compounds to become lead compounds in the pursuit of DprE1 inhibitors for TB treatment.

We describe herein a method for transition‐metal‐free (hetero)arylsulfonylation of 1‐iodopyrrolo[1,2‐a]quinoxalines with sodium arylsulfinates. The corresponding aryl iodides were in situ prepared from eletrophilic iodination of C1−H bonds in pyrrolo[1,2‐a]quinoxalines with N‐iodosuccinimide. The ensuing sulfonylation only required DMSO as solvent and completed after 15 min. Many arylsulfinates bearing chloro, bromo, methylsufonyl, acetamide, and nitro groups were competent substrates. Heteroarylsulfonylation of pyrrolo[1,2‐a]quinoxalines were also feasible. [ABSTRACT FROM AUTHOR]

A series of pyrrolo[3,2‐f]quinoxaline derivatives have been obtained by a three‐component domino reaction of quinoxalin‐6‐amine, arylglyoxal monohydrates, and cyclic 1,3‐dicarbonyl compounds in ethanol medium at 80°C catalyzed by acetic acid. The notable features of this synthesis are excellent regioselectivity, operational simplicity, relatively mild reaction conditions, and good yields. [ABSTRACT FROM AUTHOR]

Herein, we report the design and synthesis of a novel series of 6-((1H-1,2,3-triazol-4-yl)methyl)-6H-indolo[2,3-b]quinoxalines (22–29) via the copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. The target compounds formed through two pathways (A and B). The structures of the newly click synthesised 1,2,3-triazole-6H-indolo[2,3-b]quinoxalines (22–29) were confirmed on the basis of their elemental analysis and spectral data. Some of these compounds exhibited significant antiproliferative effects against tested cancer cells, including hepatocellular carcinoma (Hep-G2), breast cancer (MCF-7), and colon cancer (HCT116), relative to healthy noncancerous control skin fibroblast cells (BJ-1) to evaluate their cytotoxic effects. Among the tested compounds, compound 27 exhibited strong activity with IC50 = 9.3 ± 1.1, 1.5 ± 0.1, 2.4 ± 0.2, and 17.3 ± 1.2 against cancer cell lines HCT-116, HepG-2, MCF-7, and BJ-1, respectively. Therefore, compound 27 was selected for further investigation. Cell cycle analysis of liver cancer (HepG-2) cells treated with 27 showed cell cycle arrest in the S and G0/G1 phases and strong apoptotic activity, as indicated by Annexin V-FITC staining. Compound 27 was also found to fit in the ATP binding pocket during docking experiments combined with molecular dynamics simulation. Lastly, we conducted a Petra/Osiris/Molinspiration (POM) study on the synthesized compound. The most promising candidates were identified by evaluating primary in silico parameters, which showed considerable differences among individual synthesized compounds. These features can promote future drug candidate design to produce better derivatives in the search for anticancer agents, particularly those with favorable ADME parameters, low toxicity, anticipated bioactivity, and bright futures. [ABSTRACT FROM AUTHOR]

The integration of photovoltaic technologies within agricultural settings, also known as agrivoltaics, is attracting increasing attention as a sustainable approach to ensure both clean energy and food supply. The success of this strategy relies on the development of innovative materials that can selectively convert specific wavelengths into energy while being transparent to photosynthetically relevant light. To this aim, here we report our endeavors in the synthesis of a new class of D‐π‐A‐π‐D quinoxaline fluorophores and their use in the preparation of wavelength‐selective luminescent solar concentrators. The dyes were expeditiously prepared following a direct arylation protocol and extensively characterized by spectroscopic analyses and computational studies. They present high light harvesting ability in the green region of the visible spectrum and good emission properties, which were fully retained in the solid state when embedded into a poly methyl methacrylate (PMMA) matrix. These materials were employed to construct LSC devices of promising efficiency, fostering further developments for the use of wavelength‐selective LSC in agrivoltaic systems. [ABSTRACT FROM AUTHOR]

Photochemical properties of terarylenes with quinoxalines bridge unit and allomaltol fragment was investigated. We have demonstrated that starting compounds with hydroxyl group in 3‐hydroxy‐4‐pyranone substituent does not undergo any photoinduced transformations. Wherein, conversion to methoxy derivatives allows one to realize photochemical 6π‐electrocyclization for considered quinoxalines. Based on data of x‐ray analysis the observed difference in reactivity is connected with the presence of hydrogen bond in hydroxyl derivatives. As a result of carried out research photochemical approach to novel benzo[a]pyrano[3,2‐c]phenazin‐4‐ones was implemented. [ABSTRACT FROM AUTHOR]

We report two methods for selective morpholinomethylation and formylation of C1 − H bonds in pyrrolo[1,2-a]quinoxalines. Reaction of pyrrolo[1,2-a]quinoxalines and morpholine using CuI catalyst, (bis(trifluoroacetoxy)iodo)benzene oxidant, and DMSO solvent yielded the morpholinomethylation products. Meanwhile, formylation of C1 − H bonds in pyrrolo[1,2-a]quinoxalines progressed in the presence of CuI catalyst, trifluoroacetic acid, and DMSO solvent. Compounds bearing halogen, methylsulfonyl, pyridine, and thiophene groups were isolated in moderate yields. [ABSTRACT FROM AUTHOR]

Quinoxaline-based compounds show promising inhibition of protoporphyrinogen oxidase (PPO), a key enzyme in chlorophyll production and a prime target for herbicide development. However, their precise molecular interactions remain largely unexplored. This study investigates 1-propyl-3-phenylquinoxalin-2(1H)-one (Qnz), a novel quinoxaline derivative designed and synthesized as a representative system. We examined its interaction, at the atomic level, with the active site of Nicotiana tabacum PPO (NtPPO) using an integrated molecular docking and DFT-based quantum mechanics cluster approach. The nature and strength of observed noncovalent interactions were theoretically evaluated using quantum theory of atoms-in-molecules (QTAIM), independent gradient model (IGM), and natural bond orbital (NBO) methods. Our analysis revealed a fascinating set of unconventional interactions that contribute to the stability of the Qnz–NtPPO complex, namely weak hydrogen bonding, homopolar dihydrogen interactions, π–stacking, and carbonyl–carbonyl interactions. Interestingly, the study uncovered the unexpected role of several less common amino acids—including Gly178, Ser235, and nonpolar aliphatic leucines—in facilitating molecular recognition. Moreover, the employed computational approaches have proven to be a powerful tool for analyzing interactions within the binding pocket. [ABSTRACT FROM AUTHOR]

An eco‐conscious, metal‐free protocol has been developed to synthesize a diverse collection of biologically and pharmacologically active quinoxaline and pyrazine derivatives. The protocol involves a one‐pot condensation of various 1,2‐diamines with 1,2‐diones using thiourea dioxide as a catalyst and water as a solvent at ambient temperature. Notably, the catalyst can be reused up to five times without any significant loss of efficacy. The green aspects of this method involved milder reaction conditions, higher yields with shorter reaction times, simple work‐up, non‐chromatographic separations, good reusability, and easy catalyst recovery by simple filtration. Moreover, the reaction is successfully accelerated to a multigram scale, making it favourable for production at a larger scale. [ABSTRACT FROM AUTHOR]

Candida ranks as among the most frequently encountered fungal infections that associated with high morbidity and mortality. Quinoxaline derivatives are a group of small molecules that showed a promising antimicrobial activity. This study aimed to investigate the fungicidal effects of 3-hydrazinoquinoxaline-2-thiol against Candida in comparison with Amphotericin B in vitro as a reference. Also, we aim to assess the efficacy of 3-hydrazinoquinoxaline-2-thiol in vivo using mice oral candidiasis model. Fifty-six Candida isolates were subjected to susceptibility testing by broth microdilution method for 3-hydrazinoquinoxaline-2-thiol and Amphotericin B. Therefore, Minimal inhibitory concentrations (MIC) were assessed and compared. The oral candidiasis mice model was used to evaluate the activity of 3-hydrazinoquinoxaline-2-thiol in vivo. Microbiological evaluation of progression and ELISA were used in this study. 3-hydrazinoquinoxaline-2-thiol was more effective than Amphotericin B against most clinical isolates of Candida albicans. Higher effectiveness was seen against Candida glabrata and Candida parapsilosis isolates. However, the efficiency against Candida tropicalis isolates varies. 3-hydrazinoquinoxaline-2-thiol was also effective against Pichia kudriavzevii and Clavispora lusitaniae. 3-hydrazinoquinoxaline-2-thiol showed a good efficacy in mice model against C. albicans cells ATCC 10231. 3-hydrazinoquinoxaline-2-thiol has shown promising antifungal and anti-inflammatory activity against different Candida species. More tests and experiments are needed. [ABSTRACT FROM AUTHOR]

A new series of quinoxaline‐sulfonamide derivatives 3–12 were synthesized using fragment‐based drug design by reaction of quinoxaline sulfonyl chloride (QSC) with different amines and hydrazines. The quinoxaline‐sulfonamide derivatives were evaluated for antidiabetic and anti‐Alzheimer's potential against α‐glucosidase, α‐amylase, and acetylcholinesterase enzymes. These derivatives showed good to moderate potency against α‐amylase and α‐glucosidase with inhibitory percentages between 24.34 ± 0.01%–63.09 ± 0.02% and 28.95 ± 0.04%–75.36 ± 0.01%, respectively. Surprisingly, bis‐sulfonamide quinoxaline derivative 4 revealed the most potent activity with inhibitory percentages of 75.36 ± 0.01% and 63.09 ± 0.02% against α‐glucosidase and α‐amylase compared to acarbose (IP = 57.79 ± 0.01% and 67.33 ± 0.01%), respectively. Moreover, the quinoxaline derivative 3 exhibited potency as α‐glucosidase and α‐amylase inhibitory with a minute decline from compound 4 and acarbose with inhibitory percentages of 44.93 ± 0.01% and 38.95 ± 0.01%. Additionally, in vitro acetylcholinesterase inhibitory activity for designed derivatives exhibited weak to moderate activity. Still, sulfonamide‐quinoxaline derivative 3 emerged as the most active member with inhibitory percentage of 41.92 ± 0.02% compared with donepezil (IP = 67.27 ± 0.60%). The DFT calculations, docking simulation, target prediction, and ADMET analysis were performed and discussed in detail. [ABSTRACT FROM AUTHOR]

A series of 3-chloro-1-aryl-4-dihydro-2H-pyrrolo[2,3-b]quinoxalin-2-ones and 3-chloro-1-aryl-6,7-dimethyl-1,4-dihydro-2H-pyrrolo[2,3-b]quinoxalin-2-ones was prepared by the condensation of o-phenylenediamine or 4,5-dimethyl-1,2-aminobenzene with N-aryl-3,4-dichloro-maleimides. All the prepared quinoxalines were tested for their antitumor activity against three human cancer cell lines (prostate cells PC3, colorectal cells Caco-2, and cervical cells HeLa), and a mammalian cell line (Vero cells). The compounds were also tested for their antibacterial properties against three different bacterial cells Escherichia coli, Bacillus spizizenii, and Pseudomonas aeruginosa. The compounds 3c, 3d, 3g, 3h, 3i and 4a, 4b, 4h showed anti-proliferative activity against the tested cell lines. Regarding their antibacterial activity, compounds 3a, 3g, 4a, and 4h showed inhibitory activity against E. coli, and B. spizizenii only. [ABSTRACT FROM AUTHOR]

Context: Due to the widely known positive contributions of the quinoxaline group in organic semiconductors, we conducted a fully computational study using quantum mechanical methods to investigate the effect of quinoxaline in the electron acceptor unit with the combination of different chalcogen atoms on the band gap of a series of donor–acceptor-donor type conjugated polymers. Using density functional theory, we mainly calculated the electronic band gap values of the structures containing four different chalcogen atoms (O, S, Se, and Te) in the electron donor and acceptor units. While chalcogendiazoloquinoxaline groups were used as the electron acceptor units, furan, thiophene, selenophene, and tellurophene were used as the donor units. Our theoretical results showed that the use of heavy chalcogen atoms in both donor and acceptor units resulted in a low band gap. Besides this, the effect of heavy chalcogen atoms used in the electron donor units is much more pronounced compared to the ones used in the acceptor units. More importantly, our findings proved that the inclusion of the chalcogendiazoloquinoxaline group instead of benzochalcogenadiazole as the acceptor unit significantly decreases the electronic band gap of the conjugated polymer. The lowest band gap was found to be 0.10 eV for the 4,9-di(tellurophen-2-yl)-[1,2,5]telluradiazolo[3,4-g]quinoxaline polymer. Methods: Conformational analysis of the monomers and their corresponding oligomers was performed at the B3LYP/LANL2DZ level of theory. Then, long-range corrected hybrid functional LC-BLYP in a combination with the LANL2DZ basis set was utilized for the calculation of electronic properties and HOMO and LUMO energy gaps of monomers and oligomers through the reoptimization of the lowest energy conformers obtained from the B3LYP/LANL2DZ calculations in the previous step. All energy minimum structures were confirmed through vibrational frequency analysis at both calculation levels. The Gaussian 09 rev. D.01 software was used for all calculations, and GaussView 5.0.9 for visualizations. [ABSTRACT FROM AUTHOR]

2,3-Bis[5-(pyren-1-yl)thiophen-2-yl]quinoxalines and 2,3-bis{5-[4-(9H-carbazol-9-yl)phenyl]thiophen-2-yl}pyrazino[2,3-f][1,10]phenanthroline were synthesized. One- and two-photon absorption and emission of the compounds were studied, the cross sections of the two-photon absorption were found to be equal to 101–476 GM in THF. Fluorescent responses of pyrene-containing fluorophores and dipyrido-annelated quinoxaline to nitroaromatic compounds and metal cations, respectively, were investigated. [ABSTRACT FROM AUTHOR]

A simple synthetic route to poorly available polycyclic systems with a [1,2,5]oxadiazolo-[3,4-b]quinoxaline backbone has been developed, which is based on the sequence of nucleophilic aromatic substitution of hydrogen and the Scholl cross-coupling. According to the data from electrochemical and photophysical measurements, the synthesized compounds can be potentially considered as the narrow-gap (from 1.97 to 2.34 eV) n-type organic semiconductors, the energy levels of which are comparable to those of top commercially available electronic semiconductors. [ABSTRACT FROM AUTHOR]

Olaquindox (OLA) and quinocetone (QCT) have been prohibited in aquatic products due to their significant toxicity and side effects. In this study, rapid and visual europium nanoparticle (EuNP)-based lateral flow strip biosensors (LFSBs) were developed for the simultaneous quantitative detection of OLA, QCT, and 3-methyl-quinoxaline-2-carboxylic acid (MQCA) in fish feed and tissue. The EuNP-LFSBs enabled sensitive detection for OLA, QCT, and MQCA with a limit of detection of 0.067, 0.017, and 0.099 ng/mL (R2 ≥ 0.9776) within 10 min. The average recovery of the EuNP-LFSBs was 95.13%, and relative standard deviations were below 9.38%. The method was verified by high-performance liquid chromatography (HPLC), and the test results were consistent. Therefore, the proposed LFSBs serve as a powerful tool to monitor quinoxalines in fish feeds and their residues in fish tissues. [ABSTRACT FROM AUTHOR]

A simple synthetic route to poorly available polycyclic systems with a [1,2,5]oxadiazolo-[3,4-b]quinoxaline backbone has been developed, which is based on the sequence of nucleophilic aromatic substitution of hydrogen and the Scholl cross-coupling. According to the data from electrochemical and photophysical measurements, the synthesized compounds can be potentially considered as the narrow-gap (from 1.97 to 2.34 eV) n-type organic semiconductors, the energy levels of which are comparable to those of top commercially available electronic semiconductors. [ABSTRACT FROM AUTHOR]

We report the efficient, sustainable one‐pot synthesis of a wide variety of N‐polyheterocycles, such as imidazo‐quinolines and quinoxalines, and furoquinolines, from easily available nitroaromatics and glycols via a molybdenum catalytic domino reduction‐imine formation‐intramolecular cyclization‐oxidation sequence. It is worth highlighting that the recycling and incorporation of the waste carbonyl byproduct, generated in the reduction step, into the final compound is realized. In addition, the overall efficiency and atom economy of the process are further improved owing to the participation of one reaction intermediate as reductant that allows lowering the amount of external reducing agent employed. [ABSTRACT FROM AUTHOR]

Background: Candida represents a prevalent fungal infection, notable for its substantial implications on morbidity and mortality rates. In the landscape of prospective treatments, quinoxaline derivatives emerge as a category of compact compounds exhibiting notable potential in addressing infections. These derivatives showcase promising antimicrobial efficacy coupled with favorable pharmacokinetic and safety characteristics. Aims: The central aim of this investigation was to examine the antifungal characteristics of 2-Chloro-3-hydrazinylquinoxaline against diverse strains of Candida and Aspergillus in vitro. Additionally, we endeavored to assess the in vivo efficacy of 2-Chloro-3-hydrazinylquinoxaline using a murine model for oral candidiasis induced by C. albicans cells ATCC 10231. Results: 2-Chloro-3-hydrazinylquinoxaline demonstrated noteworthy effectiveness when tested against various reference strains of Candida species. It exhibited heightened efficacy, particularly against Candida krusei isolates. However, its performance against Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, and Candida auris isolates exhibited variability. Notably, 2-Chloro-3-hydrazinylquinoxaline manifests variable efficacy against Aspergillus fumigatus, Aspergillus niger, Aspergillus terreus and Aspergillus flavus and no effect against Aspergillus brasiliensis. In a murine model, 2-Chloro-3-hydrazinylquinoxaline exhibited significant efficacy in combating the C. albicans cells ATCC 10231 strain, underscoring its potential as a viable treatment option. Conclusion: 2-Chloro-3-hydrazinylquinoxaline has demonstrated substantial potential in effectively addressing various Candida and Aspergillus species, showcasing dual attributes of antifungal and anti-inflammatory properties. However, to attain a more comprehensive understanding of its therapeutic capabilities, further investigations, incorporating additional tests and experiments, are imperative. [ABSTRACT FROM AUTHOR]

Heterocycles are very common in many naturally occurring bioactive compounds as well as in the commercially available drug molecules. Very recently spiroheterocycles have gained considerable attention due to their wide range of pharmacological applicability. Among many others, 11H‐indeno[1,2‐b]quinoxalin‐11‐one in recent time have gained significant attention as an important building block to prepare structurally diverse biologically promising spiroheterocycles under various reaction conditions. On the other hand, it was found that one‐pot three‐component reaction strategy plays an important role in the preparation of spiroheterocycles starting from 11H‐indeno[1,2‐b]quinoxalin‐11‐one as it has many advantages including high atom economy, operational simplicity, easy workup procedures, reduction of byproducts, energy and reaction step efficiency etc. In this review, we have discussed all the recent developments related to the one‐pot three‐component synthesis of biologically promising indenoquinoxaline fused spiroheterocycles starting from 11H‐indeno[1,2‐b]quinoxalin‐11‐ones under diverse reaction conditions. [ABSTRACT FROM AUTHOR]

The main objective of the present work is to synthesize and identify the potential breast cancer medication of 2-aryl quinoxaline -derivatives via in silico investigations. Synthesis of 2-aryl quinoxaline derivatives have been achieved via the reaction of 3-aroylmethylene-2H-indol-2-ones 1 with various 1,2-diamines. Good yields were obtained at 60 °C in methanol by using graphene oxide (GO) as catalyst, however, the regio selectivity in case of unsymmetrically substituted diamines were low to moderated. This is the first report of the oxidative cleavage of C = C bond during the course of the reaction. Molecular docking study of these synthesized compounds were employed to calculate the binding affinity with human epidermal growth factor receptor 2 (HER2). 6-Bromo-3-phenylpyrido[2,3-b]pyrazine 3k showed highest binding energy of −7.70 kcal/mol depicting the potential inhibitor of HER2 receptor protein. However, this study needs to be supported by in vitro and in vivo studies. [ABSTRACT FROM AUTHOR]

ABSTRACT Purpose: Bioactive molecules are relevant to fight cancer and associated conditions. Quinoxaline is a privileged N-heterocycle, notably as anticancer agents. Herein, we report the evaluation of the quinoxaline derivatives DEQX and OAQX as anticancer agents, as well as in function of their anti-inflammatory and analgesic activities. Methods: Quinoxalines were synthesized and tested as anticancer agents based on cell viability and Annexin V-FITC apoptosis. Anti-inflammatory activity was evaluated from mouse carrageenan peritonitis and levels of interleukin (IL)-1β and tumor necrosis factor (TNF)-alfa for enzyme-linked immunosorbent assay. Hot-plate and acetic acid-induced writing test were employed to investigate analgesia. Results: Both reduced the Ht-29 cell viability in a dependent-concentration manner (p < 0.001). Total apoptosis was detected for cells treated with 12.5 and 25 µg/mL of both the compounds for 24 and 48 h (all doses, p < 0.0001). DEQX (all doses, p < 0.01) and OAQX (all doses, p < 0.001) acted in leukocyte migration and decreased the IL-1β and TNF-β levels (p < 0.05). DEQX (all doses, p < 0.05) and OAQX (5mg/kg, p < 0.001) showed peripheral analgesic effect. Conclusions: In-vitro and in-vivo results suggest that these quinoxalines are promising for application in pharmacological area due to their anticancer, anti-inflammatory, and peripheric analgesia.

This study introduces novel Liquid Organic Hydrogen Carriers (LOHCs) derived from quinoxaline. It shows that strategically incorporating N atoms and methyl groups markedly improves the hydrogen release kinetics. This structural modulation optimizes the adsorption properties and enables low-temp C–H bond activation, providing valuable insights for developing efficient LOHCs. [ABSTRACT FROM AUTHOR]

Dyes based on quinoline and quinoxaline skeletons were designed for application as visible light photoinitiators. The obtained compounds absorb electromagnetic radiation on the border between ultraviolet and visible light, which allows the use of dental lamps as light sources during the initiation of the photopolymerization reaction. Their another desirable feature is the ability to create a long-lived excited state, which enables the chain reaction to proceed through the mechanism of intermolecular electron transfer. In two-component photoinitiating systems, in the presence of an electron donor or a hydrogen atom donor, the synthesized compounds show excellent abilities to photoinitiate the polymerization of acrylates. In control tests, the efficiency of photopolymerization using modified quinoline and quinoxaline derivatives is comparable to that obtained using a typical, commercial photoinitiator for dentistry, camphorquinone. Moreover, the use of the tested compounds requires a small amount of photoinitiator (only 0.04% by weight) to initiate the reaction. The research also showed a significant acceleration of the photopolymerization process and shortening of the reaction time. In practice, this means that the new two-component initiating systems can be used in much lower concentrations without slowing down the speed of obtaining polymer materials. It is worth emphasizing that these two features of the new initiating system allow for cost reduction by reducing financial outlays on both materials (photoinitiators) and electricity. [ABSTRACT FROM AUTHOR]

We present a new category of quinoxaline di-N-oxides (QdNOs) containing amino acid side chains with dual antituberculosis and antileishmanial activity. These compounds were synthesized by combining a regioselective 2,5-piperazinedione opening and a Beirut reaction and were screened for their activity against Mycobacterium tuberculosis and the promastigote and amastigote forms of representative species of the Leishmania genus. Most QdNOs exhibited promising antitubercular activity with IC50 values ranging from 4.28 to 49.95 μM, comparable to clinically established drugs. Structure–activity relationship analysis emphasized the importance of substituents on the aromatic ring and the side chain. Antileishmanial tests showed that some selected compounds exhibited activity comparable to the positive control miltefosine against promastigotes of Leishmania amazonensis and Leishmania donovani. Notably, some compounds were found to be also more potent and less toxic than miltefosine in intracellular amastigote assays against Leishmania amazonensis. The compound showing the best dual antitubercular and leishmanicidal profile and a good selectivity index, 4h, can be regarded as a hit compound that opens up new opportunities for the development of integrated therapies against co-infections. [ABSTRACT FROM AUTHOR]

The cytotoxic activity, EGFR/VEGFR2 target inhibition, apoptotic activity, RT-PCR gene expression, in vivo employing a solid-Ehrlich carcinoma model, and in silico investigations for highlighting the binding affinity of eight quinoxaline derivatives were tested for anticancer activities. The results showed that compound 8 (N-allyl quinoxaline) had potent cytotoxicity against A594 and MCF-7 cancer cells with IC50 values of 0.86 and 1.06 µM, respectively, with noncytotoxic activity against WISH and MCF-10A cells having IC50 values more than 100 µM. Furthermore, it strongly induced apoptotic cell death in A549 and MCF-7 cells by 43.13% and 34.07%, respectively, stopping the cell cycle at S and G1-phases. For the molecular target, the results showed that compound 8 had a promising EGFR inhibition activity with an IC50 value of 0.088µM compared to Sorafenib (IC50 = 0.056 µM), and it had a promising VEGFR2 inhibition activity with an IC50 value of 0.108µM compared to Sorafenib (IC50 = 0.049 µM). Treatment with compound 8 ameliorated biochemical and histochemical parameters near normal in the in vivo investigation, with a tumor inhibition ratio of 68.19% compared to 64.8% for 5-FU treatment. Finally, the molecular docking study demonstrated the binding affinity through binding energy and interactive binding mode inside the EGFR/VEGFR2 proteins. Potent EGFR and VEGFR2 inhibition of compound 8 suggests its potential for development as a selective anticancer drug. [ABSTRACT FROM AUTHOR]

Creation of new fluorophores is important for understanding the structure–property relationship, by which the required optical properties are likely to be attained. Herein, through theory calculation, it is found that furan‐modified thiadiazolo quinoxaline acting as an electron acceptor can endow donor–acceptor–donor (D–A–D) type second near‐infrared (NIR‐II) fluorophores with longer emission wavelength than the other thiadiazolo quinoxaline‐based acceptors containing pyridine, pyrrole, thiophene, and phenyl groups, respectively. On the basis of this theoretical prediction, a D–A–D type NIR‐II fluorophore with 6,7‐di(furan‐2‐yl)‐[1,2,5]thiadiazolo[3,4‐g] quinoxaline (DFTQ) as the acceptor and dithieno[3,2‐b:2′,3′‐d]pyrrole (DTP) as the donor is designed and synthesized, and the aggregation‐induced emission (AIE) function is further achieved by introducing the AIE units of tetraphenylethylene (TPE) and triphenylamine (TPA), respectively, totally forming three NIR‐II fluorophores DFTQ–DTP, DFTQ–DTPE, and DFTQ–DTPA. For biological applications, the fluorophores are encapsulated by amphiphilic DSPE–PEG2000 to generate water‐dispersible nanoparticles (NPs). Almost the whole emission of each of the NPs falls into the NIR‐II spectral range, with part emission beyond 1300 nm. By using DFTQ–DTPA NPs as the contrast and photothermal therapy (PTT) agent, high‐resolution in vivo fluorescence imaging is achieved in the greater than 1300 nm window, and their good performance in photoacoustic imaging and high tumor PTT efficacy in tumor‐bearing mice are also demonstrated. Taken together, this work mainly provides a strong electron acceptor for constructing long‐emitting fluorophores, and by using the electron acceptor, a AIE fluorophore with desirable quantum yield (QY) and photothermal conversion efficienciy (PCE) is synthesized and demonstrated to be promising in fluorescence/photoacoustic imaging and PTT. [ABSTRACT FROM AUTHOR]

Here, a cyclometalated Pt(II) clamshell dimer (complex 2) has been synthesized with the primary ligand of dibenzo(f,h)quinoxaline and an ancillary ligand of N,N′-diphenylformamidine. In addition, a mononuclear Pt(II) complex 1a and a binuclear Pt(II) complex 1b were also prepared. Complex 1a was coordinated by one cyclometalated ligand of dibenzo(f,h)quinoxaline, one chloride ion, and one N,N′-diphenylformamidine. Complex 1b was coordinated by one cyclometalated ligand of dibenzo(f,h)quinoxaline, two chloride ions, and two N,N′-diphenylformamidines. All of these three complexes were characterized by nuclear magnetic resonance (NMR) spectroscopy, high-resolution mass spectrometry (HRMS), elemental analyses, and single-crystal X-ray diffraction (XRD). The Pt–Pt distance in complex 2 was 2.8439(2) Å. It also exhibited a near-infrared (near-IR) emission at 887 nm in the pure solid state. On the other hand, complexes 1a and 1b exhibited triplet emission at 589 and 660 nm, respectively, in the pure solid state. Furthermore, in 2 wt% poly(Me methacrylate) (PMMA) films, complex 1a showed a triplet emission at 548 nm (with Φ = 84% and τ = 5.53 μs) and complex 1b showed an emission at 627 nm (with Φ = 79% and τ = 4.07 μs). Due to its great photophysical properties, complex 1b was deposited onto quartz plates for the detection of organic solvent vapors and it showed unique emission quenching for the vapor of tetrahydrofuran. [ABSTRACT FROM AUTHOR]

This manuscript describes the development of alkyne addition to the aziridine moiety of aziridinoquinoxalines using dual Ir(III)/Cu(I) catalytic system under green light‐emitting diode (LED) photolysis (λmax=525 nm). This mild method features high levels of chemo‐ and regioselectivity and was used to generate 30 highly functionalized substituted dihydroquinoxalines in 36–98 % yield. This transformation was also carried asymmetrically using phthalazinamine‐based chiral ligand to provide 9 chiral addition products in 96 : 4 to 86 : 14 e.r. The experimental and quantum chemical explorations of this reaction suggest a mechanism that involves Ir(III)‐catalyzed triplet energy transfer followed by a ring‐opening reaction ultimately leading to the formation of azomethine ylide intermediates. These azomethine intermediates undergo sequential protonation/copper(I) acetylide addition to provide the products. [ABSTRACT FROM AUTHOR]

In the title compound, C17H12N2O,the quinoxaline moiety shows deviations of 0.0288 (7) to -0.0370 (7) Å from the mean plane (r.m.s. deviation of fitted atoms = 0.0223 Å). In the crystal, corrugated layers two molecules thick are formed by C--H⋯N hydrogen bonds and π-stacking interactions. [ABSTRACT FROM AUTHOR]

The Y-type compound 67dTPA-FQ combining 2-phenylfuro[2,3-b]quinoxaline (FQ) with triphenylamine (TPA) demonstrated to be a green fluorescence emitter (519 nm) with a ΔES1T1 of 0.40 eV. Herein, TPA units in 67dTPA-FQ were replaced with 10-phenyl-10H-phenoxazine (Ph-PXZ) units to shift the S1 energy to a lower direction to reduce ΔES1T1 and realize thermally-activated delayed fluorescence (TADF). Thus, Y-shaped (67dPXZ-FQ) and T-shaped (58dPXZ-FQ) compounds were synthesized. As the donor changed from TPA to PXZ, the emission bands of the Y- and T-shaped compounds in toluene shifted to 585 nm and 631 nm, respectively. As we expected, ΔES1T1 for Y- and T-shaped compounds decreased to 0.12 eV and 0.15 eV, respectively, well lower than 0.3 eV. Unfortunately, the TADF feature was not observed. Theoretical calculations revealed that the HOMO and LUMO orbitals of both compounds were completely located at one of the PXZ fragment and 2-phenylfuro[2,3-b]quinoxaline moiety, respectively, yielding a complete electron separation by phenylene bridges between the acceptor FQ and PXZ. As a result, the oscillator strength (f) of the S1 → S0 transition was only 0.0001–0.0002, leading to weak radiative transition capability of the S1 state. As a result, a low fluorescent yield of 25–36% was obtained. Moreover, the calculated spin–orbital coupling value between the S1 and T1 was only 0.13 cm−1 for both 67dPXZ-FQ and 58dPXZ-FQ, suggesting weak driving capability for the reverse intersystem crossing process. As such, the TADF features of the two compounds were not observed. [ABSTRACT FROM AUTHOR]

2-Chloro-3-substituted quinoxalines (3) are significant precursors in the synthesis of 2,3-di-unsymmetrically substituted quinoxalines, including quinacillin, which has been shown to be effective against a number of transplantable diseases and cancer cells. Despite the fact that there are two ways to produce 2-chloro-3-substituted quinoxalines (3), both procedures are hampered by high temperatures, metal contamination, and toxic reagents. A visible-light-induced radical cascade cyclization of ortho-diisocyanoarenes (1) with alkyl(aryl)sulfinic acids (2) and trichloroisocyanuric acid has been developed. Also, a plausible reaction mechanism and synthetic uses of 2-chloro-3-substituted quinoxalines (3) towards a few 2,3-di-unsymmetrically-substituted quinoxalines have been described. This novel approach easily accesses 2-chloro-3-substituted quinoxalines (3) in good yields, without using elevated temperatures, or metal- or toxic reagents. [ABSTRACT FROM AUTHOR]

In this study, we synthesized sulfamic acid-functionalized Fe3O4 nanoparticles (Fe3O4@EDA-SO3H) as an effective nanomagnetic solid acid catalyst. This magnetically recoverable catalyst was well characterized by FT-IR, XRD, TGA, VSM, SEM, EDX, TEM, and CHN techniques. The prepared catalyst exhibited high efficiency in the synthesis of quinoxaline, benzothiazole, and benzoxazole derivatives such as 3,2-diphenylquinoxaline (97%), 2-phenyl-benzothiazole (97%), and 2-(4-chlorophenyl)benzoxazole (95%) via simple and mild conditions. The catalyst can be readily separated from the reaction medium by employing an external magnet and reused several times without significant loss of its catalytic activity. [ABSTRACT FROM AUTHOR]

We designed and synthesized thirty novel quinoxaline aryl ethers as anticancer agents, and the structures of final compounds were confirmed with various analytical techniques like Mass, 1H NMR, 13C NMR, FTIR, and elemental analyses. The compounds were tested against three cancer cell lines: colon cancer (HCT‐116), breast cancer (MDA‐MB‐231), prostate cancer (DU‐145), and one normal cell line: human embryonic kidney cell line (HEK‐293). The obtained results indicate that two compounds, FQ and MQ, with IC50 values < 16 μM, were the most active compounds. Molecular docking studies revealed the binding of FQ and MQ molecules in the active site of the c‐Met kinase (PDB ID: 3F66, 1.40 Å). Furthermore, QikProp ADME prediction and the MDS analysis preserved those critical docking data of both compounds, FQ and MQ. Western blotting was used to confirm the impact of the compounds FQ and MQ on the inhibition of the c‐Met kinase receptor. The apoptosis assays were performed to investigate the mechanism of cell death for the most active compounds, FQ and MQ. The Annexin V/7‐AAD assay indicated apoptosis in MDA‐MB‐231 cells treated with FQ and MQ, with FQ (21.4%) showing a higher efficacy in killing MDA‐MB‐231 cells than MQ (14.25%). The Caspase 3/7 7‐AAD assay further supported these findings, revealing higher percentages of apoptotic cells for FQ‐treated MDA‐MB‐231 cells (41.8%). The results obtained from the apoptosis assay conclude that FQ exhibits better anticancer activity against MDA‐MB‐231 cells than MQ. [ABSTRACT FROM AUTHOR]

In the title compound, C31H24N4O2, the quinoxaline units are distinctly non-planar and twisted end-to-end. In the crystal, C--H…O and C--H…N hydrogen bonds link the molecules into chains extending along the a-axis direction. The chains are linked through π-stacking interactions between inversion-related quinoxaline moieties. [ABSTRACT FROM AUTHOR]

Unfused‐ring acceptors with different electron‐deficient central units, dithieno[3,2‐f:2′,3′‐h]quinoxaline (KS40) and dithieno[3,2‐e:2′,3′‐g]‐2,1,3‐benzoxadiazole (KS41) are synthesized and characterized. When blended with PM6, KS40 with a weaker electron‐accepting quinoxaline exhibits a much higher open‐circuit voltage (VOC) of 0.945 V. As a result, the KS40‐based device achieves a power conversion efficiency (PCE) of 12.2%. PM6:KS41‐based devices, in contrast, afford improved charge mobilities as well as suppressed recombination behavior, which eventually leads to an improvement in the fill factor (72.4%). Consequently, the device is able to achieve a PCE of 11.6%. [ABSTRACT FROM AUTHOR]

The pharmacological importance of quinoxaline derivatives in antibacterial research is well recognized. This study focuses on the synthesis of new 2,3‐dichloroquinoxaline derivatives containing thioether/ether groups to explore their potential as potent antibacterial agents against various pathogenic bacteria. Most of the compounds exhibited significant antibacterial properties comparable to the standard drug chlorhexidine (CHX). The derivatives of 2‐chloro‐3‐(arylthiol)quinoxaline demonstrated efficacy against Escherichia coli with minimum inhibitory concentrations (MIC) of 2.5 mg/mL and minimum bactericidal concentrations (MBC) of 2.5 to 5.0 mg/mL. These derivatives also showed similar sensitivity to Bacillus pumilus. In addition, molecular docking simulations were performed to investigate the interaction between the synthesized compounds and the DNA gyrase protein (PDB ID: 1KZN), a target for antibiotics. Among the synthesized compounds, 2,3‐bis(3‐nitrophenoxy)quinoxaline exhibited the most favourable docking score of −8.36 kcal/mol, with a binding affinity comparable to that of the reference ligand clorobiocin (−9.3 kcal/mol). [ABSTRACT FROM AUTHOR]

Functional groups adjacent to the redox active center would have an uncompromising effect on the diffusion kinetics of the charge carriers. They expedite the diffusion process by extensive H-bonding, charge delocalization, and functional group polarization by tautomerism or resonance which would have long held influence on the electrochemical performance of the material. Herein, we introduced a ketonic functional group adjacent to the quinoxaline redox center which accelerates the diffusion of the charge carriers. Quinoxaline nuclei with free rotating phenyl rings (DAB) exhibited a specific capacitance of 156.4 mAhg−1 at 50 mAg−1 which was found drastically decreased due to the excessive dissolution of the material as well as the uncontrolled ring flipping of the phenyl rings. By introducing a ketone functional group and stagnant phenyl rings with a fused ring system the specific capacitance was found to be improved to a considerable extent. The quinoxaline redox center with a fused ring system and symmetrically placed ketone functional groups (TKQ) exhibited a specific capacitance of 286.7 mAhg−1 at 50 mAg−1 and remained 224.8 mAhg−1 after prolonged 1000 cycles, with 95% coulombic efficiency and 79.4% retention in the discharge capacity. The study suggests that smart molecular engineering is necessary for excellent rate performance, rate reversibility, coulombic efficiency, and capacity retention. [ABSTRACT FROM AUTHOR]

A visible-light-promoted formal [2 + 2 + 1] cyclization of N-aryl glycines with quinoxalin-2(1H)-ones to synthesize tetrahydroimidazo[1,5-a]quinoxalin-4(5H)-ones have been developed. The protocol features operational simplicity, mild reaction conditions with blue LED light employing Ru(bpy)3Cl2. 6H2O as a photoredox catalyst, a combination of O2 from air and Cu(OAc)2 as the oxidant and broad substrate applicability. [ABSTRACT FROM AUTHOR]

Due to their benefits like low cost, simple processing, mass production, and effective conversion of solar energy into electrical energy, dye-sensitized solar cell (DSSC) devices have garnered a lot of attention in the scientific community over the past few years. It is well known that the architecture and composition of the photosensitizers play a key role in improving the functioning of the DSSC. Among the many types of fundamental units, benzimidazole and quinoxaline architectures have been particularly effective in the fabrication of DSSCs due to their extreme flexibility. The main aim of this review discussion is to focus on the application of benzimidazole and quinoxaline dyes in DSSC. Incorporating benzimidazole and quinoxaline units into dyes with a D−π−A arrangement showed enhance light-harvesting, optoelectronic, electrochemical, and photovoltaic capabilities while preventing electron recombination processes. Moreover, the maximum efficiency of benzimidazole when incorporated as ancillary donor, main donor, acceptor, n-spacer and ligand have been demonstrated. Therefore, the performance of quinoxaline dyes based on internal acceptor with one donor at (5, 8), double donor at (5, 8), double donor at (2, 3) positions as well as fused quinoxaline-Indolo based donor unit have been received a particular attention in this work. This comparative and comprehensive overview provides up-to-date knowledge and may serve as a lighthouse for young aspiring researchers interested in exploring molecular engineering potential for creating and synthesizing more efficient exotic materials for solar cells. [ABSTRACT FROM AUTHOR]

This review article provides a comprehensive overview of recent advancements in electron transport materials derived from quinoxaline, along with their applications in various electronic devices. We focus on their utilization in organic solar cells (OSCs), dye-sensitized solar cells (DSSCs), organic field-effect transistors (OFETs), organic-light emitting diodes (OLEDs) and other organic electronic technologies. Notably, the potential of quinoxaline derivatives as non-fullerene acceptors in OSCs, auxiliary acceptors and bridging materials in DSSCs, and n-type semiconductors in transistor devices is discussed in detail. Additionally, their significance as thermally activated delayed fluorescence emitters and chromophores for OLEDs, sensors and electrochromic devices is explored. The review emphasizes the remarkable characteristics and versatility of quinoxaline derivatives in electron transport applications. Furthermore, ongoing research efforts aimed at enhancing their performance and addressing key challenges in various applications are presented.

A cascade one‐pot strategy to construct 31 examples of furo‐fused quinoxalines in up to 88% yields has been devised from readily accessible β‐ketothioamides and quinoxalin‐2‐ones in open flask at room temperature under TBHP mediated conditions. Mechanistic studies revealed that the overall reactivity relies on the seamless integration of intermolecular radical coupling and intramolecular cyclization via desulfhydration of C=S bond cleavage. Generation of H2S as the only by‐product makes this process highly attractive. Furthermore, the photophysical behavior of the furo‐fused quinoxalines has also been studied. [ABSTRACT FROM AUTHOR]

Quinoxaline is a heterocyclic compound with a two-membered ring structure that undergoes redox cycling to produce toxic free radicals. It has antiviral, antibacterial, antifungal, and antitumor activities. However, the biological functions that are involved in mounting a response against the toxic effects of quinoxaline have not been investigated. Herein, we performed a genome-wide screen using the yeast haploid mutant collection and reported the identification of 12 mutants that displayed varying sensitivity towards quinoxaline. No mutant was recovered that showed resistance to quinoxaline. The quinoxaline-sensitive mutants were deleted for genes that encode cell cycle function, as well as genes that belong to other physiological pathways such as the vacuolar detoxification process. Three of the highly sensitive gene-deletion mutants lack the DDC1, DUN1, and MFT1 genes. While Ddc1 and Dun1 are known to perform roles in the cell cycle arrest pathway, the role of Mft1 remains unclear. We show that the mft1Δ mutant is as sensitive to quinoxaline as the ddc1Δ mutant. However, the double mutant ddc1Δ mft1Δ lacking the DDC1 and MFT1 genes, is extremely sensitive to quinoxaline, as compared to the ddc1Δ and mft1Δ single mutants. We further show that the mft1Δ mutant is unable to arrest in the G2/M phase in response to the drug. We conclude that Mft1 performs a unique function independent of Ddc1 in the cell cycle arrest pathway in response to quinoxaline exposure. This is the first demonstration that quinoxaline exerts its toxic effect likely by inducing oxidative DNA damage causing cell cycle arrest. We suggest that clinical applications of quinoxaline and its derivatives should entail targeting cancer cells with defective cell cycle arrest. [ABSTRACT FROM AUTHOR]

It is shown that the reaction of conjugated ynones containing a phosphoryl group with o‐phenylenediamines can, depending on the conditions, lead to the selective formation of phosphorylated 1,5‐benzodiazepines and quinoxalines. Phosphorylated quinoxalines can be used for synthesis of substituted vinyl quinoxalines. [ABSTRACT FROM AUTHOR]

A cobalt‐catalyzed annulation of o‐phenylenediamines and internal alkynes for the synthesis of quinoxalines is developed. This method provides a variety of quinoxalines in good to high yields under a simple and mild reaction conditions with molecular O2 as a terminal oxidant. Preliminary mechanistic studies show that a novel reaction mechanism is involved in the current reaction, which is different from the previous reported dicarbonyl compound mechanism via the oxidation of the alkyne. [ABSTRACT FROM AUTHOR]

A simple method for the preparation of 2-aryl-3-(2-aminoaryl)quinoxalines from 2-alkynylnitrobenzenes and 1,2-diaminoarenes was described. The reactions could proceed under mild conditions. The 1-nitro-2-(phenylethynyl)benzenes, simple starting materials, could generate the key intermediate 3H-indole-3-ones in situ in the presence of PPh3. After a cyclization with 1,2-diaminobenzenes, the 3H-indole-3-ones were then transformed into biologically valuable quinoxalines. [ABSTRACT FROM AUTHOR]