Pentafulvenes are a unique class of compounds that originally attracted attention due to their propensity to display nonbenzenoid aromaticity. Subsequently, they were recognized as valuable synthons ...for the construction of a wide range of compounds by virtue of their ability to display multiple cycloaddition profiles. Naturally, this area of organic chemistry has experienced rapid growth over the last five decades, fueled by elegant work showcasing the unique reactivity of pentafulvenes in a plethora of cycloaddition reactions. In this Review, we have attempted to provide a systematic account of the methods for the generation of pentafulvenes, their rich and varied cycloaddition chemistry, organometallic reactions, and theoretical studies that support their versatility. Further, we have highlighted their applications in the synthesis of a variety of complex structural frameworks. It is our conviction that this Review will be useful to a wide range of chemists, and will spur further research in this promising area.
The carbonyl moiety is one of the indispensable sub-units in organic synthesis with significant applications in medicinal as well as materials chemistry. Hence the insertion of a carbonyl group
via
...simple and highly efficient routes has been one of the most challenging tasks for organic chemists. Though the direct utilisation of CO gas in carbonylation is the fundamental procedure for the construction of carbonyl compounds, it has certain drawbacks due to its toxic and explosive nature. As a result, the need for cheap and efficient CO surrogates has gained much attention nowadays by which CO gas can be easily generated
in situ
or
ex situ
. In this review we discuss the advantages of chloroform as CO surrogate and have surveyed recent carbonylation reactions where chloroform has been used as CO source.
Transition-metal-catalyzed carbonylation reaction using chloroform as CO surrogate to synthesize carbonylated heterocyclic moieties.
Phenanthridine derivatives are one of the most intensively studied families of biologically active compounds. There has been considerable scientific interest in the turn of this century in the ...synthesis of these N‐containing heterocycles as they are prevalent in many alkaloids and also possess striking biological activities including antibacterial, antifungal, antitumor activities. In this regard, a number of synthetic approaches toward the construction of phenanthridine moieties with various substituents, and to increase their yield have been developed by the synthetic organic community. Even though many researchers have developed various innovative methods for the synthesis of phenanthridine derivatives for the past few years, still there is substantial scope for the discovery of novel synthetic methods. In this review, the latest developments in the diverse synthetic strategies of phenanthridine derivatives in the presence and absence of metals were described. The present review also enlightens the use of different reagents, the diversity of the substrates identified, and the plausible mechanisms unravelled towards the construction of these biologically relevant scaffolds.
Green and sustainable smart coatings with multiple functionalities that exhibit an excellent response to triggers, are essential in order to reduce energy consumption, usage of fossil resources, and ...to enhance economic impact. In the current work, oxyresveratrol (OXY) is extracted from coconut shell waste and subsequently used as a green corrosion inhibitor, encapsulated in mesoporous silica (MSNP) nanocontainers. Castor oil is a non-edible vegetable oil; it is epoxidized and crosslinked with bio-sourced citric acid and reinforced with oxyresveratrol-silica nanoparticles. The bio-based composite coating showed excellent anti-corrosive properties with improved thermal stability. At 2 wt% of OXY-MSNP content, the corrosion potential shifted to −0.028 V from −0.666 V, and the corrosion current reduced significantly from 30.53 μA cm
−2
to 0.0074 μA cm
−2
with an inhibition efficiency of 99.97%. The corrosive protection was found to be effective in 3.5 wt% NaCl solutions of acidic, neutral, and basic media, thus demonstrating the suitability of the coating in all environments. The coating also showed complete self-healing potential within 48 h, as confirmed by SEM micrographs, Electrochemical Impedance Spectroscopy and Potentiodynamic Polarisation studies. The coating inhibited the growth of both Gram-positive (
S. aureus
) and Gram-negative (
E. coli
) bacteria revealing a strong antibacterial effect. This type of bio-based self-sanitizing composite coating paves the way for the development of multifunctional smart coatings with self-healing, antimicrobial and anticorrosion properties from waste material in a sustainable manner.
Green and sustainable smart coatings with multiple functionalities that exhibit an excellent response to triggers, are essential in order to reduce energy consumption, usage of fossil resources, and to enhance economic impact.
Display omitted
•(-)-Ampelopsin F (AmF) isolated from Vatica chinensis L.•Cells treated with AmF exhibited a significant increase in insulin secretion potential in Beta-TC-6 cell lines.•AmF-treated ...cells showed an elevation in intracellular calcium concentration.•AmF upregulated the expression of GLUT2 and glucokinase.•AmF effectively inhibited the activity of DPP4.
Resveratrol oligomers, ranging from dimers to octamers, are formed through regioselective synthesis involving the phenoxy radical coupling of resveratrol building blocks, exhibiting remarkable therapeutic potential, including antidiabetic properties. In this study, we elucidate the mechanistic insights into the insulin secretion potential of a resveratrol dimer, (-)-Ampelopsin F (AmF), isolated from the acetone extract of Vatica chinensis L. stem bark in Pancreatic Beta-TC-6 cell lines. The AmF (50 µM) treated cells exhibited a 3.5-fold increase in insulin secretion potential as compared to unstimulated cells, which was achieved through the enhancement of mitochondrial membrane hyperpolarization, elevation of intracellular calcium concentration, and upregulation of GLUT2 and glucokinase expression in pancreatic Beta-TC-6 cell lines. Furthermore, AmF effectively inhibited the activity of DPP4, showcasing a 2.5-fold decrease compared to the control and a significant 6.5-fold reduction compared to the positive control. These findings emphasize AmF as a potential lead for the management of diabetes mellitus and point to its possible application in the next therapeutic initiatives.
Pterospermum rubiginosum is an evergreen plant in Western Ghats, India, used by traditional tribal healers due to its excellent biological potential for treating inflammation and pain relief ...procedures. The bark extract is also consumed to relieve the inflammatory changes at the bone fractured site. The traditional medicinal plant in India have to be characterized for its diverse phytochemical moieties, its interactive multiple target sites, and to reveal the hidden molecular mechanism behind the biological potency.
The study focussed on plant material characterization, computational analysis (prediction study), toxicological screening (In vivo), and anti-inflammatory evaluation of P. rubiginosum methanolic bark extracts (PRME) in LPS-induced RAW 264.7 cells.
The pure compound isolation of PRME and their biological interactions were used to predict the bioactive components, molecular targets, and molecular pathways of PRME in inhibiting inflammatory mediators. The anti-inflammatory effects of PRME extract were evaluated in the lipopolysaccharide (LPS)-induced RAW264.7 macrophage cell model. The toxicity evaluation of PRME was performed in healthy 30 Sprague–Dawley experimental rats, were randomly divided into five groups for toxicological evaluation for 90 days. The tissue levels of oxidative stress and organ toxicity markers were measured using the ELISA method. Nuclear magnetic resonance spectroscopy (NMR) was performed to characterize the bioactive molecules.
Structural characterization revealed the presence of vanillic acid, 4-O-methyl gallic acid, E-resveratrol, gallocatechin, 4′-O-methyl gallocatechin, and catechin. Molecular docking of NF-kB exhibited significant interactions with vanillic acid and 4-O-methyl gallic acid with binding energy −351.159 Kcal/Mol and −326.5505 Kcal/Mol, respectively. The PRME-treated animals showed an increase in total GPx and antioxidant levels (SOD and catalase). Histopathological examination revealed no variation in the liver, renal and splenic tissue's cellular pattern. PRME inhibited the pro-inflammatory parameters (IL-1β, IL-6, and TNF-α) in LPS-induced RAW 264.7 cells. The protein level of TNF-α and NF-kB protein expression study brought out a notable reduction and exhibited a good correlation with the gene expression study.
The current study establishes the therapeutic potential of PRME as an effective inhibitory agent against LPS-activated RAW 264.7 cells induced inflammatory mediators. Long-term toxicity evaluation on SD rats confirmed the non-toxic nature of PRME up to 250mg/body weight for 3 months.
Display omitted
•The phytochemical characterization revealed the presence of vanillic acid, 4-O-methylgallic acid, E-resveratrol, gallocatechin, 4-O-methylgallocatechin, and catechin from PRME.•Molecular docking studies confirmed the drugability of phytochemicals isolated from PRME.•Molecular docking evaluation of NF-kB exhibited significant interactions with vanillic acid and 4-O-methylgallic acid with remarkable binding energy.•Long-term toxicity evaluation on Sprague-Dawley rats confirmed that PRME is non-toxic up to 250mg/body weight for 3 months.•The current study establishes the therapeutic potential of PRME as an effective anti-inflammatory agent against LPS-activated RAW 264.7 cells induced inflammatory mediators.
Smart multifunctional epoxy coating prepared by incorporating bio-nanocomposites of two isolated phytochemicals bergenin and malabaricone C in mesoporous silica nanoparticles showed excellent ...corrosion inhibition property. This smart antimicrobial and corrosion resistant coating was active in acidic, basic and neutral media containing 3.5 wt% NaCl. The coatings exhibit their best performance in near neutral media. Polarisation studies and EIS data showed that an epoxy composite coating containing 3% bergenin nanocomposite prevents corrosion on mild steel and aluminium alloys far better than a pure epoxy coating. Quantitative and qualitative analysis of the antimicrobial action of the coatings revealed that malabaricone C is an excellent antimicrobial agent in smart coating showing 99.99% efficiency, and the coating exhibited activity against both gram positive and negative bacteria like S. aureus and P. aeruginosa.
Display omitted
•Green corrosion inhibitors developed from V. indica and M. malabarica•Bergenin-malabaricone C composite show excellent corrosion inhibition efficiency.•Modified coating is effective for both aluminium and mild steel protection.•Coating was effective against both gram positive and gram negative bacteria.
Abstract
Copper-mediated carbon–heteroatom bond-forming reactions involving a wide range of substrates have been in the spotlight for many organic chemists. This review highlights developments ...between 2010 and 2019 in both stoichiometric and catalytic copper-mediated reactions, and also examples of nickel-mediated reactions, under modified Chan–Lam cross-coupling conditions using various nucleophiles; examples include chemo- and regioselective N-arylations or O-arylations. The utilization of various nucleophiles as coupling partners together with reaction optimization (including the choice of copper source, ligands, base, and other additives), limitations, scope, and mechanisms are examined; these have benefitted the development of efficient and milder methods. The synthesis of medicinally valuable or pharmaceutically important nitrogen heterocycles, including isotope-labeled compounds, is also included. Chan–Lam coupling reaction can now form twelve different C–element bonds, making it one of the most diverse and mild reactions known in organic chemistry.
1 Introduction
2 Construction of C–N and C–O Bonds
2.1 C–N Bond Formation
2.1.1 Original Discovery via Stoichiometric Copper-Mediated C–N Bond Formation
2.1.2 Copper-Catalyzed C–N Bond Formation
2.1.3 Coupling with Azides, Sulfoximines, and Sulfonediimines as Nitrogen Nucleophiles
2.1.4 Coupling with
N
,
N
-Dialkylhydroxylamines
2.1.5 Enolate Coupling with sp
3
-Carbon Nucleophiles
2.1.6 Nickel-Catalyzed Chan–Lam Coupling
2.1.7 Coupling with Amino Acids
2.1.8 Coupling with Alkylboron Reagents
2.1.9 Coupling with Electron-Deficient Heteroarylamines
2.1.10 Selective C–N Bond Formation for the Synthesis of Heterocycle-Containing Compounds
2.1.11 Using Sulfonato-imino Copper(II) Complexes
2.2 C–O Bond Formation
2.2.1 Coupling with (Hetero)arylboron Reagents
2.2.2 Coupling with Alkyl- and Alkenylboron Reagents
3 C–Element (Element = S, P, C, F, Cl, Br, I, Se, Te, At) Bond Forma tion under Modified Chan–Lam Conditions
4 Conclusions
Antimicrobial resistance transmission from farm animals to humans is a critical health concern and hence a detailed molecular surveillance is essential for tracking the spread and consequent ...evolution of antimicrobial resistance. In this study, a pan-drug resistant Klebsiella pneumoniae MS1 strain was isolated from a healthy broiler farm and studied. From the results of the study, MS1 was found to be is resistant to 18 tested antibiotics and has a high-risk to be pathogenic to humans with a probability of 0.80. The whole genome sequencing data of MS1 was used to predict the presence of antimicrobial resistance genes and pathogenicity. The genome analysis has revealed MS1 to have 34 AMR genes. Out of these, the AMR gene OmpK37 codes for an important protein involved in cell permeability and hence in antibiotic resistance. Further analysis was carried out by using an in-genome analysis method to understand the evolution of OmpK37 and the underlying reason for the emergence of resistance. From the detailed analysis, the current study could demonstrate for the first time the evolution of OmpK37 from OmpC. Though structurally OmpK37 was very similar to other porins present in MS1, it was found to have higher mutability as a distinguishing feature which makes it an important protein in monitoring the evolving resistances in microorganisms.
Display omitted
•The whole genome sequencing of Klebsiella pneumoniae MS1 isolated from poultry feces was done.•Phenotypic and genotypic characterisation of antimicrobial resistance was conducted using Vitek-2 and CARD database.•Evolution of AMR genes in the genome was identified using a novel clustering and phylogenetic approach.•Evolution of OmpK37 was studied using phylogenetic approach.
Promalabaricone B (PMB), an acylphenol was isolated from dichloromethane-soluble extract of the seeds of
Houtt. PMB exhibited significant inhibitory activity on
-glucosidase enzyme. The molecular ...docking and dynamics studies of PMB with human maltase-glucoamylase were performed. PMB exhibited an enhanced glucose uptake in L6 myotubes with 46.3% in 2.5
M. Encouraged with these results; we investigated the molecular mechanism of PMB through the upregulation of AMPK. The results revealed that PMB promoted the glucose uptake in myocytes by stimulating the translocation and expression of GLUT4. From this, it is clear that PMB can acts as a potential therapeutic option for diabetes treatment, and its hypoglycaemic effect may be mediated by AMPK upregulation and induction of GLUT4 translocation.
