Benzofuran derivatives and their anti-tubercular, anti-bacterial activities

A formal [4 + 1] annulation incorporating styrylogous aldol condensation to access functionalized 2-styryl-benzofurans

Despite the well-established aldol reaction and its vinylogous variants, the styrylogous version has been scarcely reported. Herein, we have introduced a styrylogous aldol condensation reaction. A novel base-mediated formal [4 + 1] annulation, integrating O-allylation and styrylogous aldol condensation, has been disclosed. This transformation involves ortho-hydroxyaryl aldehydes/ketones in conjunction with distally-activated cinnamyl (pseudo)halides. The presented transition metal-free process forms C-O and CC bonds, enabling the synthesis of functionalized 2-styryl-benzofuran derivatives in moderate to good yields. The application potential of the developed method has been demonstrated in the efficient syntheses of 2-aminostyryl-benzofuran derivatives, which have proven to act as potent inhibitors for Aβ fibril formation related to Alzheimer's disease (AD).

Acid-Regulated Selective Synthesis of Benzofuran Derivatives via Single-Component BDA Retro-Aldol/Michael Addition Cascade and [4 + 2] Cycloaddition Reactions

The acid-controlled single-component retro-aldol/Michael addition cascade reaction and [4 + 2] cycloaddition of benzofuran-derived azadienes (BDAs) are reported for the first time. Under the conditions of trifluoromethanesulfonic acid as the catalyst and with the addition of water, BDAs initiate the retro-aldol reaction, followed by a 1,4-Michael addition, yielding (arylmethylene)bis(dibenzofuran) products with excellent yields and broad substrate applicability. This represents the first application of BDAs in a retro-aldol reaction. In contrast, in the absence of water and with boron trifluoride etherate as the catalyst, BDAs undergo a [4 + 2] cycloaddition reaction, constructing the spiro[benzofuran-2,3'-benzofuro[3,2-b]pyridine] framework with high yields and diastereoselectivity. The method features mild conditions and high atom economy, and provides a new approach for constructing benzofuran scaffold derivatives.

Efficient strategy for alleviating neuronal apoptosis and oxidative stress damage of Alzheimer's disease through dual targeting BCL-2 gene promoter i-motif and β-amyloid

Alzheimer's disease (AD) is a severe neurodegenerative disorder characterized by abnormal metabolism of β-amyloid (Aβ) precursor proteins and neuronal apoptosis, ultimately leading to cognitive dysfunction. The pathogenesis of AD is complex, and current single-target therapies are not effective in preventing the rapid progression of AD, which highlights the urgent need for developing multi-target drugs. In this study, a series of compounds were synthesized through a multi-targeting ligand strategy. After extensive screening and evaluation, we found a lead compound B14, which showed excellent dual targeting ability for effectively alleviating neuronal apoptosis and oxidative stress damage of AD. In our molecular and cellular level experiments, B14 could target and stabilize the i-motif structure formed on the BCL-2 promoter to upregulate BCL-2 expression, which could also bind to Aβ and inhibit its deposition. In the Aβ1-42-induced cell model, B14 could maintain mitochondrial function and number, regulate intracellular reactive oxygen species (ROS) and Ca2+ metabolism disorders, and effectively reduce Aβ1-42-induced apoptosis. Further studies showed that B14 also exhibited good ability to cross the blood-brain barrier (BBB), which significantly improved learning memory and cognitive deficits, reduced brain Aβ plaques, alleviated inflammation and restored oxidative stress markers in APP/PS1 mice. Our findings provide an innovative strategy of dual targeting BCL-2 promoter i-motif for transcriptional regulation and Aβ aggregation synergistically for mitigating AD pathologies. B14 represents a promising multi-target lead compound with a good potential for further development for AD treatment.

Regiodivergent and Enantioselective Allylic C-H Alkylation of Allyl Ethers: Optimization, Scope, Mechanism and Application

Vinyl ethers and allyl ethers are important motifs in natural products and pharmaceuticals. Among various methods toward their synthesis, direct allylic C-H functionalization of allyl ethers is one of the most efficient approaches. In this study, one of two regioisomers, a vinyl ether or an allyl ether, could be obtained, depending on whether a Lewis acid co-catalyst was present. Furthermore, branched allyl ethers were smoothly prepared in excellent regio- and enantioselectivity (up to 20 : 1 b/l, 99 % ee) by synergistic catalysis with an achiral Pd(0) complex and a chiral Lewis acid catalyst.

Traditional utilization, botany, phytochemistry, pharmacology, pharmaceutical analysis, processing and application of the seeds of Herpetospermum pedunculosum (Ser.) C.B. Clarke: a comprehensive review

The seed of Herpetospermum pedunculosum (Ser.) C.B. Clarke, known in Chinese as Bo-Leng-Gua-Zi and in Tibetan as Sejimedo, are here abbreviated as H. pedunculosum seeds. Herpetospermum pedunculosum seeds is a traditional Chinese medicine for protecting the liver, clearing heat, and detoxifying. A total of 125 chemical metabolites of H. pedunculosum seeds are found, including lignans, fatty acids, terpenes, coumarins, and others. The pharmacological activities of H. pedunculosum seeds are mainly in hepatoprotective, antioxidant, anti-cancer cells, and anticholestatic effects. In clinical application, it is mainly used in combination with other traditional Chinese medicines to play a key role in treating the liver disease. This paper gives a systematic review of above research aspects, proposes the potential limitations and put forward plausible solutions. Relevant literatures were searched in PubMed, Web of Science and Chinese National Knowledge Infrastructure with Herpetospermum as the key word. A number of studies have shown that H. pedunculosum seeds exert excellent hepatoprotective effects by acting on NF-κB, TGF-β, and Keap1-Nrf2 signaling pathways, which provide a solid base for its clinic application. However, more research is needed to explore the standard cultivation and quality evaluation of H. pedunculosum seeds and systematical structure-activity relationship of its active metabolites.

Synthesis and anti-tumor activity of new benzofuran-based chalcone derivatives as potent VEGFR-2 inhibitors

Cancer is one of the most significant public health problems worldwide, and the discovery and development of efficient VEGFR-2 inhibitors has been a research hotspot in cancer treatment. In the present work, a series of novel benzofuran-based chalcone derivatives have been prepared, and in vitro anti-tumor activities of them have been evaluated. The results indicated that the compounds displayed potent anticancer activity against HCC1806, HeLa and A549 cell lines. The preliminary mechanism study showed that 4g could effectively induce the apoptosis of HCC1806 cells, and showed inhibitory effect on VEFGR-2. The molecular docking study indicated that 4g had an obvious binding site with the target VEGFR-2 (PDB ID: 4BSK). Therefore, the benzofuran-based chalcone derivatives could be considered as potent VEGFR-2 inhibitors.

Recent trends for chemoselectivity modulation in one-pot organic transformations

In organic reactions, chemoselectivity refers to the selective reactivity of one functional group in the presence of another. This can be more successful if the reagent and reaction parameters are appropriately chosen. One-pot reactions have been shown to be an effective structural variety technique for the development of novel heterocyclic or carbocyclic compounds. This review article focuses on recent efforts by researchers from around the world to synthesise novel organic molecules utilising these methodologies (2013-2024), as well as their mechanism insights. The substrate, catalyst, solvent, and temperature conditions all have a significant impact on chemoselectivity in the organic reactions described here. The manipulation of chemoselectivity in organic processes creates new potential for the production of novel heterocycles and carbocycles.

Synthesis of Benzofuran Derivatives via a DMAP-Mediated Tandem Cyclization Reaction Involving ortho-Hydroxy α-Aminosulfones

An efficient cascade cyclization strategy was developed to synthesize aminobenzofuran spiroindanone and spirobarbituric acid derivatives utilizing 2-bromo-1,3-indandione, 5-bromo-1,3-dimethylbarbituric acid, and ortho-hydroxy α-aminosulfones as substrates. Under the optimized reaction conditions, the corresponding products were obtained with high efficiency, exceeding 95% and 85% yields for the respective derivatives. This protocol demonstrates exceptional substrate versatility and robust scalability up to the Gram scale, establishing a stable platform for the synthesis of 3-aminobenzofuran derivative. The successful synthesis paves the way for further biological evaluations with potential implications in scientific research.

Synthesis, Biological Properties, and Molecular Docking Study of Novel 1,2,3-Triazole-8-quinolinol Hybrids

A new series of 1,2,3-triazole-8-quinolinol hybrids were synthesized in good yields using monosubstituted acetonitriles and 5-azidomethyl-8-quinolinol as the starting reagents via a one-step protocol. The structures of 1,2,3-triazole-8-quinolinol hybrids were characterized by nuclear magnetic resonance (1H and 13C NMR) spectroscopy and elemental analysis. Antibacterial activity in vitro of all the synthesized hybrids was investigated against Escherichia coli (E. coli), Xanthomonas fragariae (X. fragariae), Staphylococcus aureus (S. aureus), and Bacillus subtilis (B. subtilis) applying the methods of disk diffusion and minimal inhibition concentration (MIC). Hybrid 7 exhibited excellent antibacterial capacity, with an MIC value of 10 μg/mL against S. aureus and 20 μg/mL against B. subtilis, E. coli, and X. fragariae, which were comparable to those that of the standard antibiotic nitroxoline. A structure-activity relationship (SAR) study of 1,2,3-triazole-8-quinolinol hybrids showed that introducing electron-donating substituents in the 1,2,3-triazole ring at the 4-position is important for activity. Quantum chemical calculations have been undertaken to employ the Gaussian software in the B3LYP, HF, and M062X basis sets using 3-21g, 6-31g, and SDD levels to further explain linkages within the antibacterial findings. Furthermore, molecular docking investigations were also conducted to investigate the binding affinities as well as the interactions of some hybrids with the target proteins. An absorption, distribution, metabolism, excretion, and toxicity (ADME/T) investigation was carried out to scrutinize the viability of employing the 1,2,3-triazole-8-quinolinol hybrids as medicines.

Diastereoselective Synthesis of Dihydrobenzofuran Spirooxindoles and Their Transformation into Benzofuroquinolinones by Ring Expansion of Oxindole Core

A mild and efficient approach for the diastereoselective synthesis of dihydrobenzofuran spirooxindoles using 3-chlorooxindoles and imines is presented. This process involves a formal [4 + 1] annulation, yielding the product with excellent diastereoselectivity. Furthermore, a novel method for constructing benzofuroquinolinone scaffolds through the ring expansion of oxindoles has been established. This method involves a lactam ring expansion to the quinolinone skeleton. Besides, a one-pot procedure for creating benzofuroquinolinone scaffolds from 3-chlorooxindoles and imines is also provided.

Synthesis of Benzofuran-Fused Oxepines through Cs2CO3-Promoted [4 + 3] Annulation of Aurones with Crotonate-Derived Sulfonium Salts

Benzofuran-fused derivatives display important and reliable therapeutic properties. Herein, we describe the synthesis of benzofuran-fused oxepines using aurones and crotonate-derived sulfonium salts via a [4 + 3] annulation reaction in the presence of Cs2CO3. This reaction proceeds under mild and operationally simple conditions. The synthetic utility of this approach was highlighted by several transformations, including the efficient synthesis of a novel tetracyclic fused benzofuran derivative.

Direct α-Arylation of Benzo[b]furans Catalyzed by a Pd3 Cluster

As an interim paradigm for the catalysts between those based on more conventional mononuclear molecular Pd complexes and Pdn nanoparticles widely used in organic synthesis, polynuclear palladium clusters have attracted great attention for their unique reactivity and electronic properties. However, the development of Pd cluster catalysts for organic transformations and mechanistic investigations is still largely unexploited. Herein, we disclose the use of trinuclear palladium (Pd3Cl) species as an active catalyst for the direct C-H α-arylation of benzo[b]furans with aryl iodides to afford 2-arylbenzofurans in good yields under mild conditions. With this method, broad substrate adaptability was observed, and several drug intermediates were synthesized in high yields. Mechanistic studies indicated that the Pd3 core most likely remained intact throughout the reaction course.

Mask and Release Strategy-Enabled Diversity-Oriented Synthesis for DNA-Encoded Library

An ideal DNA-encoded library (DEL) selection requires the library to consist of diverse core skeletons and cover chemical space as much as possible. However, the lack of efficient on-DNA synthetic approaches toward core skeletons has greatly restricted the diversity of DEL. To mitigate this issue, this work disclosed a "Mask & Release" strategy to streamline the challenging on-DNA core skeleton synthesis. N-phenoxyacetamide is used as a masked phenol and versatile directing group to mediate diversified DNA-compatible C-H functionalization, introducing the 1st-dimensional diversity at a defined site, and simultaneously releasing the phenol functionality, which can facilitate the introduction of the 2nd diversity. This work not only provides a set of efficient syntheses toward DNA-conjugated drug-like core skeletons such as ortho-alkenyl/sulfiliminyl/cyclopropyl phenol, benzofuran, dihydrobenzofuran but also provides a paradigm for on-DNA core skeleton synthetic method development.

Copper ion-based chemical elicitation induces production of new benzofurans in Anthostomella brabeji, an endophytic fungus of Paepalanthus planifolius

The present work reports the effects of chemical elicitors and epigenetic modifiers on the production and diversification of secondary metabolites produced by Anthostomella brabeji - an endophytic fungus isolated from Paepalanthus planifolius (Eriocaulaceae). The fungus was cultivated under four different small-scale culture conditions in potato dextrose broth (PDB): PDB (control), PDB + Mg+2, PDB + Cu+2 and PDB + 5-AZA (5-azacytidine). The incorporation of Cu+2 into PDB medium yielded the most promising results as the most significant differences in the metabolic profile of A. brabeji were observed under this condition. The chemical analysis of the PDB + Cu+2 extract resulted in the isolation of seven metabolites, including three new benzofuran derivatives (2, 4 and 6) and four known compounds (1, 3, 5 and 7). The metabolites were tested using the Gram-positive bacterium Staphylococcus aureus, Gram-negative bacteria Salmonella sp. and Escherichia coli, and six yeasts of Candida albicans and non-albicans. The EtOAc extract (PDB + Cu+2), and compounds 1, 2 and 7 exhibited relevant antifungal activity against Candida spp., with minimum inhibitory concentration ranging from 62.5 to 500.0 μg/mL.

Uterine microbial communities and their potential role in the regulation of epithelium cell cycle and apoptosis in aged hens

BACKGROUND

Alterations of the uterine microbiome are closely associated with various intrauterine diseases and physiological conditions, which are well-established in mammals. However, as representative oviparous animals, the research on the uterine microbial ecosystem and its functions with physiological homeostasis is limited in chickens. Additionally, continuous egg-laying disrupts the oviducal immune defenses of aged hens, susceptible to pathogen invasion, causing poor egg quality and food-borne infections in humans. Here, we investigated aging-related changes in the oviduct microbial colonization and transmission from the gut to eggs and their roles in a hen model.

RESULTS

The results of 16S rDNA sequencing showed significant differences in the oviduct microbial composition between young (38 weeks) and aged (77 weeks) laying hens. SourceTracker analysis further revealed differences in the effects of microbial transmission on the oviducal microbiota between young and aged hens. Enhanced barrier defense with cell apoptosis suppression and cell cycle arrest of the uterus were observed in aged hens reducing microbial transmission from the lower to upper reproductive tract. In addition, a total of 361 significantly differential metabolites were identified using metabolomics in the aged uterine microbiota, especially in products of amino acid metabolism and biosynthesis of various secondary metabolites, which might have essential effects on cell apoptosis by regulating immune responses and cell cycle. Notably, antibiotics disrupted uterine microbiota by dietary intervention and direct perfusion did not retard aging-related physiological changes but further aggravated aging processes by disrupting the cell cycle and apoptosis.

CONCLUSIONS

The microbiota continuum along the reproductive tract in aged birds differs from that in young birds, especially with a significant shift in the uterus. The aged uterine microbiota probably contributes to the regulation of cell cycle and apoptosis by microbial metabolites primarily involved in amino acid metabolism and biosynthesis of various secondary metabolites. These findings provide new insights into the roles of the reproductive tract microbiota in regulating the cell programming of the aged host, contributing to the exploration of the microbiome as a target for diagnosing aging health status and therapy for gynecological diseases in women. Video Abstract.

Helichrysum stoechas (L.) Moench Inflorescence Extract for Tomato Disease Management

Helichrysum stoechas is a singular halophyte that has been shown to have anti-inflammatory, antioxidant, and allelopathic properties. In the work presented herein, we have characterized its inflorescences hydromethanolic extract and assessed its antifungal activity for the pre- and postharvest management of tomato crop diseases. Gas chromatography-mass spectrometry characterization of the extract showed that 4-ethenyl-1,3-benzenediol, 2,3-dihydro-benzofuran, quinic acid, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-1-benzopyran-4-one, 1,6-anhydro-β-D-glucopyranose, catechol, scopoletin, and maltol were the main constituents. The co-occurrence of pyranones, benzenediols, and quinic acids as phytoconstituents of H. stoechas extract resulted in promising in vitro minimum inhibitory concentrations of 500, 375, 500, 187.5, 187.5, and 375 μg·mL-1 against mycelia of Alternaria alternata, Colletotrichum coccodes, Fusarium oxysporum f. sp. lycopersici, Rhizoctonia solani, Sclerotinia sclerotiorum, and Verticillium dahliae, respectively. Further, to assess the potential of H. stoechas inflorescence extract for postharvest tomato crop protection, ex situ tests were conducted against C. coccodes, obtaining high protection at a dose of 750 μg·mL-1. Taking into consideration that the demonstrated activity is among the highest reported to date for plant extracts and comparable to that of the synthetic fungicides tested as positive controls, H. stoechas inflorescence extract may be put forward as a promising biorational and may deserve further testing in field-scale studies.

In Silico Development of Novel Benzofuran-1,3,4-Oxadiazoles as Lead Inhibitors of M. tuberculosis Polyketide Synthase 13

Benzofuran and 1,3,4-oxadiazole are privileged and versatile heterocyclic pharmacophores which display a broad spectrum of biological and pharmacological therapeutic potential against a wide variety of diseases. This article reports in silico CADD (computer-aided drug design) and molecular hybridization approaches for the evaluation of the chemotherapeutic efficacy of 16 S-linked N-phenyl acetamide moiety containing benzofuran-1,3,4-oxadiazole scaffolds BF1-BF16. This virtual screening was carried out to discover and assess the chemotherapeutic efficacy of BF1-BF16 structural motifs as Mycobacterium tuberculosis polyketide synthase 13 (Mtb Pks13) enzyme inhibitors. The CADD study results revealed that the benzofuran clubbed oxadiazole derivatives BF3, BF4, and BF8 showed excellent and remarkably significant binding energies against the Mtb Pks13 enzyme comparable with the standard benzofuran-based TAM-16 inhibitor. The best binding affinity scores were displayed by 1,3,4-oxadiazoles-based benzofuran scaffolds BF3 (-14.23 kcal/mol), BF4 (-14.82 kcal/mol), and BF8 (-14.11 kcal/mol), in comparison to the binding affinity score of the standard reference TAM-16 drug (-14.61 kcal/mol). 2,5-Dimethoxy moiety-based bromobenzofuran-oxadiazole derivative BF4 demonstrated the highest binding affinity score amongst the screened compounds, and was higher than the reference Pks13 inhibitor TAM-16 drug. The bindings of these three leads BF3, BF4, and BF8 were further confirmed by the MM-PBSA investigations in which they also exhibited strong bindings with the Pks13 of Mtb. Moreover, the stability analysis of these benzofuran-1,3,4-oxadiazoles in the active sites of the Pks13 enzyme was achieved through molecular dynamic (MD) simulations at 250 ns virtual simulation time, which indicated that these three in silico predicted bio-potent benzofuran tethered oxadiazole molecules BF3, BF4, and BF8 demonstrated stability with the active site of the Pks13 enzyme.

Redox-neutral rhodium(III)-catalyzed divergent synthesis of tetrasubstituted 1,3-enynes and alkynylated benzofurans

With the assistance of the acetamido directing group (DG), a rhodium-catalyzed C-H alkenylation/DG migration cascade for the synthesis of tetrasubstituted 1,3-enynes from N-phenoxyacetamides and 1,3-diynes has been achieved in this work. Alternatively, a rhodium-catalyzed [3 + 2] annulation for the synthesis of alkynylated benzofurans from the same set of substrates has also been achieved by simply changing the reaction conditions. This work highlights the tunable divergent synthesis of valuable compounds triggered by C-H activation.

Recent Advances in Gold(I)-Catalyzed Approaches to Three-Type Small-Molecule Scaffolds via Arylalkyne Activation

Gold catalysts possess the advantages of water and oxygen resistance, with the possibility of catalyzing many novel chemical transformations, especially in the syntheses of small-molecule skeletons, in addition to achieving the rapid construction of multiple chemical bonds and ring systems in one step. In this feature paper, we summarize recent advances in the construction of small-molecule scaffolds, such as benzene, cyclopentene, furan, and pyran, based on gold-catalyzed cyclization of arylalkyne derivatives within the last decade. We hope that this review will serve as a useful reference for chemists to apply gold-catalyzed strategies to the syntheses of related natural products and active molecules, hopefully providing useful guidance for the exploration of additional novel gold-catalyzed approaches.

A minireview of 1,2,3-triazole hybrids with O-heterocycles as leads in medicinal chemistry

Over the past few decades, the dynamic progress in the synthesis and screening of heterocyclic compounds against various targets has made a significant contribution in the field of medicinal chemistry. Among the wide array of heterocyclic compounds, triazole moiety has attracted the attention of researchers owing to its vast therapeutic potential and easy preparation via copper and ruthenium-catalyzed azide-alkyne cycloaddition reactions. Triazole skeletons are found as major structural components in a different class of drugs possessing diverse pharmacological profiles including anti-cancer, anti-bacterial, anti-fungal, anti-viral, anti-oxidant, anti-inflammatory, anti-diabetic, anti-tubercular, and anti-depressant among various others. Furthermore, in the past few years, a significantly large number of triazole hybrids were synthesized with various heterocyclic moieties in order to gain the added advantage of the improved pharmacological profile, overcoming the multiple drug resistance and reduced toxicity from molecular hybridization. Among these synthesized triazole hybrids, many compounds are available commercially and used for treating different infections/disorders like tazobactam and cefatrizine as potent anti-bacterial agents while isavuconazole and ravuconazole as anti-fungal activities to name a few. In this review, we will summarize the biological activities of various 1,2,3-triazole hybrids with copious oxygen-containing heterocycles as lead compounds in medicinal chemistry. This review will be very helpful for researchers working in the field of molecular modeling, drug design and development, and medicinal chemistry.

Synthesis of Novel Ferrocene-Benzofuran Hybrids via Palladium- and Copper-Catalyzed Reactions

The combination of the ferrocene skeleton with pharmacophores often leads to molecules with interesting biological properties. Five ferrocene-benzofuran hybrids of different structures were synthesized by transition metal catalyzed reactions. The efficiency of both homogeneous and heterogeneous catalytic methods was tested. The products were characterized using 1H, 13C NMR and FTIR spectroscopy, HRMS and cyclic voltammetry. The structure of one of the new compounds was also proved with X-ray crystallography. The new hybrids showed moderate cytotoxicity on MCF-7 and MDA-MB-231 cell lines. It is remarkable that the less curable MDA-MB-231 cell line was more sensitive to treatment with three ferrocene derivatives.

Gold(I)-Catalyzed Tandem Cyclization/Hydroarylation of o-Alkynylphenols with Haloalkynes

A convenient and mild protocol for the gold-catalyzed intermolecular coupling of o-alkynylphenols with haloalkynes to give vinyl benzofurans is reported. In this work, the gold catalyst SIPrAuCl and the co-catalyst NaBARF would corporately promote the intramolecular cyclization of the o-alkynylphenol to benzofuran, and then a selective hydroarylation of benzofuran to haloalkyne was catalyzed by the same catalysts. Computational studies suggest that the hydroarylation process takes place via a concerted nucleophilic attack pathway of the benzofuran to the C2 carbon of the activated haloalkyne, and reveal the original driving force of this hydroarylation process.

Selective synthesis of 3-formylbenzofuran and 3-acylbenzofuran using a chalcone rearrangement strategy

We developed a method for highly selective synthesis of two benzofuran isomers, by rearranging and subsequently transforming 2-hydroxychalcones. Depending on the reaction conditions, synthesis of 3-formylbenzofurans, unconventional products, and 3-acylbenzofurans was achieved through cyclized 2,3-dihydrobenzofurans obtained from the rearranged products. The facile synthesis of 3-formylbenzofurans facilitated synthesis of the natural product, puerariafuran, from the corresponding chalcone.

Visible-Light-Promoted bis(Difluoromethylation)/Cyclization of 2-Vinyloxy Arylalkynes to Prepare Benzofuran Derivatives

A visible-light-promoted difluoromethylation/cyclization of 2-vinyloxy arylalkynes was developed, providing a variety of bis(difluoromethyl)-substituted benzofurans in moderate to good yields. A plausible mechanism involving difluoromethyl radical cascade cyclization and solvent-promoted ionic addition was proposed. This protocol has the advantages of having mild reaction conditions, simple operation, and good functional group tolerance.

Recent Progress in the Development of Novel Mycobacterium Cell Wall Inhibitor to Combat Drug-Resistant Tuberculosis

Despite decades of research in drug development against TB, it is still the leading cause of death due to infectious diseases. The long treatment duration, patient noncompliance coupled with the ability of the tuberculosis bacilli to resist the current drugs increases multidrug-resistant tuberculosis that exacerbates the situation. Identification of novel drug targets is important for the advancement of drug development against Mycobacterium tuberculosis. The development of an effective treatment course that could help us eradicates TB. Hence, we require drugs that could eliminate the bacteria and shorten the treatment duration. This review briefly describes the available data on the peptidoglycan component structural characterization, identification of the metabolic pathway, and the key enzymes involved in the peptidoglycan synthesis, like N-Acetylglucosamine-1-phosphate uridyltransferase, mur enzyme, alanine racemase as well as their inhibition. Besides, this paper also provides studies on mycolic acid and arabinogalactan synthesis and the transport mechanisms that show considerable promise as new targets to develop a new product with their inhibiter.

Synthesis, characterization and antibiotic evaluation of some novel (E)-3-(4-diphenylamino)phenyl)-1-(4′-fluorophenyl)prop-2-en-1-one chalcones and their analogues

Background

The increase in resistance of pathogenic organisms to the available chemotherapeutic agents are critical challenges in drug design and development, motivating researchers to look for novel compounds that can combat multidrug-resistant organisms. Recently, chalcones have been proved to be attractive moieties in drug discovery.

Results

Eight novel triphenylamine chalcones with different substitution patterns were successfully synthesized via the conventional Claisen–Schmidt condensation reaction in an alkaline medium at room temperature, and recrystallized using ethanol, the percentage yield of the compounds were between 30 and 92%. The structures of the synthesized chalcones were successfully characterized and confirmed using FT-IR, NMR spectroscopic and GC–MS spectrometric techniques.

Conclusions

The results of the biological studies showed that all the synthesized chalcones possess remarkable activities against the tested microbes, by showing a significant zone of inhibitions relative to that of the standard drugs used. The investigation revealed that 1b showed highest ZOI (30 mm), lowest MIC (12.5 µg/ml) and MBC/MFC (50 µg/ml) on Aspergillus niger. Therefore, displayed better antifungal potential as compared to the rest of the compounds, and can be a potential antifungal drug candidate.

Structure-Activity Relationship of Benzofuran Derivatives with Potential Anticancer Activity

Benzofuran is a heterocyclic compound found naturally in plants and it can also be obtained through synthetic reactions. Multiple physicochemical characteristics and versatile features distinguish benzofuran, and its chemical structure is composed of fused benzene and furan rings. Benzofuran derivatives are essential compounds that hold vital biological activities to design novel therapies with enhanced efficacy compared to conventional treatments. Therefore, medicinal chemists used its core to synthesize new derivatives that can be applied to a variety of disorders. Benzofuran exhibited potential effectiveness in chronic diseases such as hypertension, neurodegenerative and oxidative conditions, and dyslipidemia. In acute infections, benzofuran revealed anti-infective properties against microorganisms like viruses, bacteria, and parasites. In recent years, the complex nature and the number of acquired or resistant cancer cases have been largely increasing. Benzofuran derivatives revealed potential anticancer activity with lower incidence or severity of adverse events normally encountered during chemotherapeutic treatments. This review discusses the structure-activity relationship (SAR) of several benzofuran derivatives in order to elucidate the possible substitution alternatives and structural requirements for a highly potent and selective anticancer activity.

Optimization of TAM16, a Benzofuran That Inhibits the Thioesterase Activity of Pks13; Evaluation toward a Preclinical Candidate for a Novel Antituberculosis Clinical Target

With increasing drug resistance in tuberculosis (TB) patient populations, there is an urgent need for new drugs. Ideally, new agents should work through novel targets so that they are unencumbered by preexisting clinical resistance to current treatments. Benzofuran 1 was identified as a potential lead for TB inhibiting a novel target, the thioesterase domain of Pks13. Although, having promising activity against Mycobacterium tuberculosis, its main liability was inhibition of the hERG cardiac ion channel. This article describes the optimization of the series toward a preclinical candidate. Despite improvements in the hERG liability in vitro, when new compounds were assessed in ex vivo cardiotoxicity models, they still induced cardiac irregularities. Further series development was stopped because of concerns around an insufficient safety window. However, the demonstration of in vivo activity for multiple series members further validates Pks13 as an attractive novel target for antitubercular drugs and supports development of alternative chemotypes.

Pd/Cu-catalyzed access to novel 3-(benzofuran-2-ylmethyl) substituted (pyrazolo/benzo)triazinone derivatives: their in silico/in vitro evaluation as inhibitors of chorismate mutase (CM)

In view of the reported chorismate mutase (CM or MtbCM) inhibitory activities of 3-indolylmethyl substituted (pyrazolo/benzo)triazinone derivatives the structurally similar 3-(benzofuran-2-ylmethyl) substituted (pyrazolo/benzo)triazinones were designed and evaluated in silico against CM. The docking of target molecules was performed at the interface site of MtbCM (PDB: 2FP2). All the best ranked molecules participated in a strong H-bonding with the ILE67 of the B chain at the backbone position in addition to several hydrophobic/van der Waals interactions with the hydrophobic residues. Based on encouraging docking results, the one-pot synthesis of newly designed benzofuran derivatives was carried out using tandem Pd/Cu-catalyzed Sonogashira cross-coupling followed by intramolecular cyclization of 2-iodophenols with appropriate terminal alkynes. A range of novel 3-(benzofuran-2-ylmethyl) substituted (pyrazolo/benzo)triazinone derivatives were prepared in high (>80%) yields. Three molecules i.e.3h, 3i and 3m that participated in good interaction with CM in silico showed encouraging (64–65%) inhibition at 30 μM in vitro. An SAR within this class of molecules suggested that the benzotriazinone series in general was better than the pyrazolotriazinone series. Based on molecular docking in silico, CM inhibition in vitro and computational ADME prediction the benzofuran derivatives 3i and 3m seemed to be of further medicinal interest in the context of discovery and development of new anti-tubercular agents.

We report the Pd/Cu-catalyzed synthesis, in silico molecular docking, in vitro CM inhibition and computational ADME prediction of novel 3-(benzofuran-2-ylmethyl) substituted (pyrazolo/benzo)triazinone derivatives.

Development of novel benzofuran-isatin conjugates as potential antiproliferative agents with apoptosis inducing mechanism in Colon cancer

In the current work, a new set of carbohydrazide linked benzofuran-isatin conjugates (5a-e and 7a-i) was designed and synthesised. The anticancer activity for compounds (5b-d, 7a, 7b, 7d and 7g) was measured against NCI-55 human cancer cell lines. Compound 5d was the most efficient, and thus subjected to the five-dose screen where it showed excellent broad activity against almost all tested cancer subpanels. Furthermore, all conjugates (5a-e and 7a-i) showed a good anti-proliferative activity towards colorectal cancer SW-620 and HT-29 cell lines, with an excellent inhibitory effect for compounds 5a and 5d (IC50 = 8.7 and 9.4 µM (5a), and 6.5 and 9.8 µM for (5d), respectively). Both compounds displayed selective cytotoxicity with good safety profile. In addition, both compounds provoked apoptosis in a dose dependent manner in SW-620 cells. Also, they significantly inhibited the anti-apoptotic Bcl2 protein expression and increased the cleaved PARP level that resulted in SW-620 cells apoptosis.

Development of 3-methyl/3-(morpholinomethyl)benzofuran derivatives as novel antitumor agents towards non-small cell lung cancer cells

As one of the most lethal malignancies, lung cancer is considered to account for approximately one-fifth of all malignant tumours-related deaths worldwide. This study reports the synthesis and in vitro biological assessment of two sets of 3-methylbenzofurans (4a-d, 6a-c, 8a-c and 11) and 3-(morpholinomethyl)benzofurans (15a-c, 16a-b, 17a-b and 18) as potential anticancer agents towards non-small cell lung carcinoma A549 and NCI-H23 cell lines, with VEGFR-2 inhibitory activity. The target benzofuran-based derivatives efficiently inhibited the growth of both A549 and NCI-H23 cell lines with IC50 spanning in ranges 1.48-47.02 and 0.49-68.9 µM, respectively. The three most active benzofurans (4b, 15a and 16a) were further investigated for their effects on the cell cycle progression and apoptosis in A549 (for 4b) and NCI-H23 (for 15a and 16a) cell lines. Furthermore, benzofurans 4b, 15a and 16a displayed good VEGFR-2 inhibitory activity with IC50 equal 77.97, 132.5 and 45.4 nM, respectively.

Asymmetric 1,4-Michael Addition Reaction of Azadienes with α-Thiocyanoindanones Catalyzed by Bifunctional Chiral Squaramide

In this paper, the organocatalytic asymmetric 1,4-Michael addition reaction of azadienes and α-thiocyanoindanones was investigated. A series of chiral benzofuran compounds containing thiocyano group and quaternary carbon center were synthesized in moderate yields with good enantioselectivities (up to 90:10 er) and high diastereoselectivities (up to >95:5 dr). This is the first case of 1,4-Michael addition reaction using α-thiocyanoindanones to obtain a series of chiral thiocyano compounds and further broaden the scope of application of azadiene substrates. In addition, a possible reaction mechanism is also described in the article.

Novel N-(2-Methoxydibenzofuran-3-yl)-2-aryloxyacetamide Derivatives: Synthesis and Biological Investigation

Background:

Dibenzofuran ring is a typical heterocyle that is found in many natural sources and its derivatives exhibit a wide scale of biological applications similar to its analog ring systems; furan and benzofuran.

Materials and Methods:

Novel N-(2-methoxydibenzofuran-3-yl)-2-aryloxyacetamide derivatives (2a-l) were synthesized and evaluated for their cytotoxic activity against A549 lung cancer and NIH/3T3 mouse embryofibroblast cell lines. The inhibition percentages of cathepsin D, L, acetylcholinesterase (AChE) and butrylcholinesterase (BuChE) enzymes provoked by the compounds were also determined.

Results and Discussion:

Most of the compounds exhibited significant cytotoxicity whose IC50 values were identified lower than the tested lowest concentration (<3.90 μg/mL). Compound 2i against cathepsin D and compound 2k against cathepsin L displayed the highest inhibitory activity. Regrettably, the compounds demonstrated very weak AChE and BuChE inhibition.

Conclusion:

Compounds 2b, 2c, 2e, 2i and 2k exhibited the highest antiproliferative activity against A549 cell lines with selective profile. However, they did not display satisfying results on tested enzymes.

Dearomative 1,6-addition of P(O)–H to in situ formed p-QM-like ion pairs from 2-benzofuryl-ols to C3-phosphinoyl hydrobenzofurans

We report a dearomative C3-phosphorylation and a tandem C3-phosphorylation/aromatization of 2-benzofuryl-ols with P(O)–H species to afford C3-phosphinoyl hydrobenzofurans and benzofurans, respectively.

N-Heterocyclic carbene catalyzed asymmetric [3 + 3] cycloaddtion of β,β-disubstituted, α,β-unsaturated carboxylic esters with 3-aminobenzofurans

An NHC-catalyzed β-carbon functionalization reaction to afford enantioenriched benzofuran fused δ-lactams bearing an all-carbon quaternary stereocenter is documented.

Copper-catalyzed one-pot synthesis of 2-(2,2,2-trifluoroethyl)-substituted benzofused heterocycles

A method for copper-catalyzed synthesis of 2-trifluoroethyl-substituted benzofurans and indoles from the reaction of salicylaldehyde/2-aminobenzaldehyde p-tosylhydrazones with 2-bromo-3,3,3-trifluoropropene has been developed.

Palladium-Catalyzed C-H Arylation of Benzofurans with Triarylantimony Difluorides for the Synthesis of 2-Arylbenzofurans

Pd-catalyzed regioselective C-H arylation is a useful tool for the chemical modification of aromatic heterocycles and 2-arylbenzofuran derivatives are of interest as biologically active substances. Herein, the reaction of triarylantimony difluorides with benzofurans under aerobic conditions in 1,2-DCE, using 5 mol% Pd (OAc)2 and 2 eq. of CuCl2 at 80 °C, produced a variety of 2-arylbenzofurans in moderate-to-high yields. The reaction is sensitive to the electronic nature of the substituents on the benzene ring of the triarylantimony difluorides: an electron-donating group showed higher reactivity than an electron-withdrawing group. Single crystal X-ray analysis of tri(p-methylphenyl) antimony difluoride revealed that the central antimony atom exhibits trigonal bipyramidal geometry.