Synthesis and antimicrobial evaluation of amide derivatives of benzodifuran-2-carboxylic acid

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.

Optimization of Osthole as a Pesticide Candidate: Synthesis, Crystal Structures, and Agrochemical Properties of Acrylate Derivatives of Isopropenyl 2,3-Dihydrobenzofurans

For high-value-added application of osthole derivatives as a pesticide candidate in crop protection, by the use of osthole as a lead compound, a series of novel acrylate derivatives of isopropenyl 2,3-dihydrobenzofurans were prepared by the successive bromination, rearrangement, and esterization reactions. Three-dimensional structures of four compounds were determined by single-crystal X-ray diffraction. The possible mechanism for construction of this new isopropenyl 2,3-dihydrobenzofuran skeleton from the osthole was presented. Against Plutella xylostella Linnaeus, compound 32 (R = PhCH2CH2) displayed 3.5-fold potent insecticidal activity of osthole. Against Tetranychus cinnabarinus Boisduval, compound 40 (LC50: 0.165 mg/mL; R = (CH2)13CH3) showed 8.3-fold pronounced acaricidal activity of osthole (LC50: 1.367 mg/mL); notably, its control effect can be comparable to that of the commercial acaricide spirodiclofen. Additionally, the scanning electron microscopy imaging method demonstrated that compound 40 can destroy the stratum corneum of T. cinnabarinus. Compound 40 can be further explored as a lead acaricidal agent.

A DR/NIR Hybrid Polymeric Tool for Functional Bio-Coatings: Theoretical Study, Cytotoxicity, and Antimicrobial Activity

Among modern biomaterials, hybrid tools containing an organic component and a metal cation are recognized as added value, and, for many advanced biomedical applications, synthetic polymers are used as thin protective/functional coatings for medical or prosthetic devices and implants. These materials require specific non-degradability, biocompatibility, antimicrobial, and antiproliferative properties to address safety aspects concerning their use in medicine. Moreover, bioimaging monitoring of the biomedical device and/or implant through biological tissues is a desirable ability. This article reports a novel hybrid metallopolymer obtained by grafting zinc-coordinated fragments to an organic polymeric matrix. This hybrid polymer, owing to its relevant emission in the deep red to near-infrared (DR/NIR) region, is monitorable; therefore, it represents a potential material for biomedical coating. Furthermore, it shows good biocompatibility and adhesion properties and excellent stability in slightly acidic/basic water solutions. Finally, in contact with the superficial layers of human skin, it shows antimicrobial properties against Staphylococcus aureus bacterial strains.

CD, UV, and In Silico Insights on the Effect of 1,3-Bis(1'-uracilyl)-2-propanone on Serum Albumin Structure

1,3-diaryl-2-propanone derivatives are synthetic compounds used as building blocks for the realization not only of antimicrobial drugs but also of new nanomaterials thanks to their ability to self-assemble in solution and interact with nucleopeptides. However, their ability to interact with proteins is a scarcely investigated theme considering the therapeutic importance that 1,3-diaryl-2-propanones could have in the modulation of protein-driven processes. Within this scope, we investigated the protein binding ability of 1,3-bis(1'-uracilyl)-2-propanone, which was previously synthesized in our laboratory utilizing a Dakin-West reaction and herein indicated as U2O, using bovine serum albumin (BSA) as the model protein. Through circular dichroism (CD) and UV spectroscopy, we demonstrated that the compound, but not the similar thymine derivative T2O, was able to alter the secondary structure of the serum albumin leading to significant consequences in terms of BSA structure with respect to the unbound protein (Δβ-turn + Δβ-sheet = +23.6%, Δα = -16.7%) as revealed in our CD binding studies. Moreover, molecular docking studies suggested that U2O is preferentially housed in the domain IIIB of the protein, and its affinity for the albumin is higher than that of the reference ligand HA 14-1 (HDOCK score (top 1-3 poses): -157.11 ± 1.38 (U2O); -129.80 ± 6.92 (HA 14-1); binding energy: -7.6 kcal/mol (U2O); -5.9 kcal/mol (HA 14-1)) and T2O (HDOCK score (top 1-3 poses): -149.93 ± 2.35; binding energy: -7.0 kcal/mol). Overall, the above findings suggest the ability of 1,3-bis(1'-uracilyl)-2-propanone to bind serum albumins and the observed reduction of the α-helix structure with the concomitant increase in the β-structure are consistent with a partial protein destabilization due to the interaction with U2O.

Protein Binding of Benzofuran Derivatives: A CD Spectroscopic and In Silico Comparative Study of the Effects of 4-Nitrophenyl Functionalized Benzofurans and Benzodifurans on BSA Protein Structure

Benzofuran derivatives are synthetic compounds that are finding an increasing interest in the scientific community not only as building blocks for the realization of new materials, but also as potential drugs thanks to their ability to interact with nucleic acids, interfere with the amyloid peptide aggregation and cancer cell cycle. However, their ability to interact with proteins is a theme still in need of investigation for the therapeutic importance that benzofurans could have in the modulation of protein-driven processes and for the possibility of making use of serum albumins as benzofurans delivery systems. To this scope, we investigated the protein binding ability of two 4-nitrophenyl-functionalized benzofurans previously synthesized in our laboratory and herein indicated as BF1 and BDF1, which differed for the number of furan rings (a single moiety in BF1, two in BDF1), using bovine serum albumin (BSA) as a model protein. By circular dichroism (CD) spectroscopy we demonstrated the ability of the two heteroaromatic compounds to alter the secondary structure of the serum albumin leading to different consequences in terms of BSA thermal stability with respect to the unbound protein (ΔT_m > 3 °C for BF1, −0.8 °C for BDF1 with respect to unbound BSA, in PBS buffer, pH 7.5) as revealed in our CD melting studies. Moreover, a molecular docking study allowed us to compare the possible ligand binding modes of the mono and difuranic derivatives showing that while BF1 is preferentially housed in the interior of protein structure, BDF1 is predicted to bind the albumin surface with a lower affinity than BF1. Interestingly, the different affinity for the protein target predicted computationally was confirmed also experimentally by fluorescence spectroscopy (k_D = 142.4 ± 64.6 nM for BDF1 vs. 28.4 ± 10.1 nM for BF1). Overall, the above findings suggest the ability of benzofurans to bind serum albumins that could act as their carriers in drug delivery applications.

Synthesis of novel indole-isoxazole hybrids and evaluation of their cytotoxic activities on hepatocellular carcinoma cell lines

BACKGROUND

Liver cancer is predicted to be the sixth most diagnosed cancer globally and fourth leading cause of cancer deaths. In this study, a series of indole-3-isoxazole-5-carboxamide derivatives were designed, synthesized, and evaluated for their anticancer activities. The chemical structures of these of final compounds and intermediates were characterized by using IR, HRMS, 1H-NMR and 13C-NMR spectroscopy and element analysis.

RESULTS

The cytotoxic activity was performed against Huh7, MCF7 and HCT116 cancer cell lines using sulforhodamine B assay. Some compounds showed potent anticancer activities and three of them were chosen for further evaluation on liver cancer cell lines based on SRB assay and real-time cell growth tracking analysis. Compounds were shown to cause arrest in the G0/G1 phase in Huh7 cells and caused a significant decrease in CDK4 levels. A good correlation was obtained between the theoretical predictions of bioavailability using Molinspiration calculation, Lipinski's rule of five, and experimental verification. These investigations reveal that indole-isoxazole hybrid system have the potential for the development of novel anticancer agents.

CONCLUSIONS

This study has provided data that will form the basis of further studies that aim to optimize both the design and synthesis of novel compounds that have higher anticancer activities.

A Novel DR/NIR T-Shaped AIEgen: Synthesis and X-Ray Crystal Structure Study

We developed a new benzodifuran derivative as the condensation product between 2,6-diamino-4-(4-nitrophenyl)benzo[1,2-b:4,5-b’]difuran-3,7-dicarboxylate and 3-hydroxy-2-naphthaldehyde. The intramolecular hydrogen-bond interactions in the terminal half-salen moieties produce a sterically encumbered highly conjugated main plane and a D-A-D (donor-acceptor-donor) T-shaped structure. The novel AIEgen (aggregation-induced enhanced emission generator) fulfils the requirement of RIR (restriction of intramolecular rotation) molecules. DR/NIR (deep red/near infrared) emission was recorded in solution and in the solid state, with a noteworthy photoluminescence quantum yield recorded on the neat crystals which undergo some mechanochromism. The crystal structure study of the probe from data collected at a synchrotron X-ray source shows a main aromatic plane π-stacked in a columnar arrangement.

Crystal structures of butyl 2-amino-5-hy-droxy-4-(4-nitro-phen-yl)benzo-furan-3-carboxyl-ate and 2-meth-oxy-ethyl 2-amino-5-hy-droxy-4-(4-nitro-phen-yl)benzo-furan-3-carboxyl-ate

The title benzo-furan derivatives 2-amino-5-hy-droxy-4-(4-nitro-phen-yl)benzo-furan-3-carboxyl-ate (BF1), C19H18N2O6, and 2-meth-oxy-ethyl 2-amino-5-hy-droxy-4-(4-nitro-phen-yl)benzo-furan-3-carboxyl-ate (BF2), C18H16N2O7, recently attracted attention because of their promising anti-tumoral activity. BF1 crystallizes in the space group P . BF2 in the space group P21/c. The nitro-phenyl group is inclined to benzo-furan moiety with a dihedral angle between their mean planes of 69.2 (2)° in BF1 and 60.20 (6)° in BF2. A common feature in the mol-ecular structures of BF1 and BF2 is the intra-molecular N-H⋯Ocarbon-yl hydrogen bond. In the crystal of BF1, the mol-ecules are linked head-to-tail into a one-dimensional hydrogen-bonding pattern along the a-axis direction. In BF2, pairs of head-to-tail hydrogen-bonded chains of mol-ecules along the b-axis direction are linked by O-H⋯Ometh-oxy hydrogen bonds. In BF1, the butyl group is disordered over two orientations with occupancies of 0.557 (13) and 0.443 (13).

Recent Development on Importance of Heterocyclic Amides as Potential Bioactive Molecules: A Review

Background:

Heterocyclic compounds are an integral part of the chemical and life sciences and constitute a considerable quantum of the modern research that is being currently pursued throughout the world.

Methods:

This review was prepared by collecting the available literature reports on various databases and an extract was prepared for each report after thorough study and compiling the recent literature reports on heterocyclic amides from 2007 to 2018.

Results:

This review summarizes the bio-potential of heterocyclic amides as antimicrobial, anticancer, anti-tubercular and antimalarial agents which would be very promising in the field of medicinal chemistry.

Conclusion:

A wide variety of heterocyclic amides have already been reported and some are currently being used as active medicaments for the treatment of disease. Still, the research groups are focusing on the development of newer heterocyclic amide derivatives with better efficacy, potency and lesser side effects. This area has got the tremendous potential to come up with new chemical entities of medicinal importance.

Quinolone derivatives and their antifungal activities: An overview

More than 300 million people suffer from the incidence of life-threatening invasive fungal infections, resulting in over 1.35 million deaths annually. Currently, the antifungal agents available in clinics are rather limited, and the rapid development of resistance to the existing antifungal drugs has further aggravated mortality. Quinolones possess a broad spectrum of chemotherapeutic properties and demonstrate considerable antifungal activities as well. Various quinolone derivatives have been screened for their antifungal activities, and some of them exhibit excellent potency against both drug-susceptible and drug-resistant fungi. This review aims to outline the recent advances in quinolone derivatives as potential antifungal agents and summarize the structure-activity relationship, to provide insights for the rational design of more active candidates.

Benzodifurans for biomedical applications: BZ4, a selective anti-proliferative and anti-amyloid lead compound

AIM

Our goal is to evaluate benzodifuran-based scaffolds for biomedical applications.

METHODOLOGY

We here explored the anticancer and anti-amyloid activities of a novel compound (BZ4) in comparison with other known benzodifuran analogs, previously studied in our group, and we have explored its ability to interact with different DNA model systems.

RESULTS

BZ4 shows antiproliferative activity on different cancer cells; does not affect noncancerous control cells and alters the aggregation properties of β-amyloid, as ascertained by circular dichroism, fluorescence spectroscopy and scanning electron microscopy analysis. An overall, qualitative picture on the mechanistic aspects related to the biological activities is discussed in light of the dynamic light scattering, UV, circular dichroism and fluorescence data, as well as of the metal ion-binding properties of BZ4.

Evaluating the biological properties of synthetic 4-nitrophenyl functionalized benzofuran derivatives with telomeric DNA binding and antiproliferative activities

Four 4-nitrophenyl-functionalized benzofuran (BF1, BF2) and benzodifuran (BDF1, BDF2) compounds were synthesized by a convenient route based on the Craven reaction. All the compounds underwent a detailed chemical-physical characterization to evaluate their structural, thermal and optical properties. An investigation on the therapeutic potential of the reported compounds was performed by analyzing their antiproliferative activity on prostatic tumour cells (PC-3). In both classes of compounds, anticancer potential is in direct correlation with the lipophilicity. From our study it emerged that antiproliferative activity was higher for benzofuran derivatives as compared to benzodifuran systems. Moreover, we report a mechanistic study relative to the most promising molecule, i.e. the apolar benzofuran BF1, that relates the antiproliferative properties found in our investigation to its ability to bind telomeric DNA (proven by CD and fluorescence techniques on tel₂₂ G4 DNA), and highlights its unexpected impact on cell cycle progression.

Benzodifuran Derivatives as Potential Antiproliferative Agents: Possible Correlation between Their Bioactivity and Aggregation Properties

To further explore the properties and bioactivity of benzodifurans, three compounds in this class were synthesised and characterised using spectroscopic and spectrometric techniques, as well as SEM and thermogravimetric analysis. The synthesised compounds showed interesting antiproliferative activity on different human cancer cells (HeLa, Hep-G2, WM266), whereas no relevant cytotoxic effect was observed on healthy control cells. To study the possible mechanism of action of the benzodifurans, their ability to bind various model DNA systems, their aggregation properties, and their ability to bind biologically relevant metal ions was evaluated. The molecules were found to form monodisperse nanoaggregates stable at physiological temperature, which are likely related to the observed bioactivity.

Synthesis and Fungicidal Activities of (Z/E)-3,7-Dimethyl-2,6-octadienamide and Its 6,7-Epoxy Analogues

In order to find new lead compounds with high fungicidal activity, (Z/E)-3,7-dimethyl-2,6-octadienoic acids were synthesized via selective two-step oxidation using the commercially available geraniol/nerol as raw materials. Twenty-eight different (Z/E)-3,7-dimethyl-2,6-octadienamide derivatives were prepared by reactions of (Z/E)-carboxylic acid with various aromatic and aliphatic amines, followed by oxidation of peroxyacetic acid to afford their 6,7-epoxy analogues. All of the compounds were characterized by HR-ESI-MS and ¹H-NMR spectral data. The preliminary bioassays showed that some of these compounds exhibited good fungicidal activities against Rhizoctonia solani (R. solani) at a concentration of 50 µg/mL. For example, 5C, 5I and 6b had 94.0%, 93.4% and 91.5% inhibition rates against R. solani, respectively. Compound 5f displayed EC₅₀ values of 4.3 and 9.7 µM against Fusahum graminearum and R. Solani, respectively.

Identification of unusual C–Cl⋯π contacts in 2-(alkylamino)-3-chloro-1,4-naphthoquinones: effect of N-substituents on crystal packing, fluorescence, redox and anti-microbial properties

XRD study demonstrates the opening of unusual C–Cl⋯π synthon in 2-(alkylamino)-3-chloro-1,4-naphthoquinone. Notably, compound holding N-pyridylmethyl exhibits enhanced activity against S. aureus and proved to be more potent than ciprofloxacin.

R. C, Chand K, Santos MA, Keri RS. Benzofuran: an emerging scaffold for antimicrobial agents

The present article systematically gives a comprehensive review of current development of benzofuran-based compounds as antimicrobial agents and the perspectives that they hold for future research.