Development of novel transition metal-catalyzed synthetic approaches for the synthesis of a dihydrobenzofuran nucleus: a review.

The synthesis of dihydrobenzofuran scaffolds bears pivotal significance in the field of medicinal chemistry and organic synthesis. These heterocyclic scaffolds hold immense prospects owing to their significant pharmaceutical applications as they are extensively employed as essential precursors for constructing complex organic frameworks. Their versatility and importance make them an interesting subject of study for researchers in the scientific community. While exploring their synthesis, researchers have unveiled various novel and efficient pathways for assembling the dihydrobenzofuran core. In the wake of extensive data being continuously reported each year, we have outlined the recent updates (post 2020) on novel methodological accomplishments employing the efficient catalytic role of several transition metals to forge dihydrobenzofuran functionalities.

Exploring the synthetic potential of epoxide ring opening reactions toward the synthesis of alkaloids and terpenoids: a review.

Epoxides are oxygen containing heterocycles which are significantly employed as crucial intermediates in various organic transformations. They are considered highly reactive three-membered heterocycles due to ring strain and they undergo epoxide ring opening reactions with diverse range of nucleophiles. Epoxide ring-opening reactions have gained prominence as flexible and effective means to obtain various functionalized molecules. These reactions have garnered substantial attention in organic synthesis, driven by the need to comprehend the synthesis of biologically and structurally important organic compounds. They have also found applications in the synthesis of complex natural products. In this review article, we have summarized the implementation of epoxide ring opening reactions in the synthesis of alkaloids and terpenoids based natural products reported within the last decade (2014-2023).

The Fluorescence Sensing Capability of 1,4-dihydroxyanthraquinone Towards Metal Ions and Imaging Cells.

Fluorescence and colorimetric sensors have gained significant traction in diverse scientific domains, including environmental, agricultural, and pharmaceutical chemistry. This article comprehensively surveys recent advancements in developing sensors employing 1,4-dihydroxyanthraquinone(1,4-DHAQ). The study delves into the unique properties of 1,4-dihydroxyanthraquinone(1,4-DHAQ) as a sensor, focusing on its capacity to detect Cu2+ ions and elucidating its fluorescence quenching mechanisms. Furthermore, the interaction of dihydroxyanthraquinone with Ga(III), Al(III), and In(III) ions is explored under both aqueous and non-aqueous conditions, leading to the formation of distinctive fluorescent species. The investigation extends to factors influencing ligand behavior, including time dependency, temperature, solvent type, counterions, and pH levels. These key parameters are systematically analyzed to understand sensor performance better. In conclusion, the article investigates the utility of the 1,4-dihydroxyanthraquinone-Zn2+ probe as a versatile sensing platform for phosphate anions, particularly in live cell imaging. The findings contribute to the evolving landscape of sensor technologies, offering insights into the diverse applications and potential advancements in this burgeoning field.

Steglich esterification: A versatile synthetic approach toward the synthesis of natural products, their analogues/derivatives.

The exploitation of natural products and their analogues in the field of pharmacology has been regarded as of great importance. It can be attributed to the fact that these scaffolds exhibit diverse chemical properties, distinct biological activities and zenith specificity in their biochemical processes, enabling them to act as favorable structures for lead compounds. The synthesis of natural products has been a crafty and hard-to-achieve task. Steglich esterification reaction has played a significant role in that area. It is a mild and efficient technique for constructing ester linkages. This technique involves the establishment of ester moiety via a carbodiimide-based condensation of a carboxylic acid with an alcohol, thiol or an amine catalyzed by dimethyl aminopyridine (DMAP). Specifically, labile reagents with multiple reactive sites are esterified efficiently with the classical and modified Steglich esterification conditions, which accounts for their synthetic utility. This review encloses the performance of the Steglich esterification reaction in forging the ester linkage for executing the total synthesis of natural products and their derivatives since 2018.

Update on novel synthetic approaches towards the construction of carbazole nuclei: a review.

The carbazole scaffold is a significant entity in organic compounds due to its variety of biological and synthetic applications. Traditionally, carbazole skeletons have been synthesized either via the Grabe-Ullman method, Clemo-Perkin method or Tauber method. With the passage of time, these methods have been modified and explored to accomplish the synthesis of target compounds. These methods include hydroarylations, C-H activations, annulations and cyclization reactions mediated by a variety of catalysts to construct carbazole-based compounds. This brief review article intends to provide recent updates on important methodological developments reported for the synthesis of carbazole nuclei covering 2019-2023.

Gilman reagent toward the synthesis of natural products.

With the ever-increasing scope of organocuprates, a well-established Gilman reagent has been considered as an unprecedented synthetic tool in modern organic chemistry. The broad research profile of the Gilman reagent (R2CuLi in THF or Et2O) is owing to its propensity to carry out three kinds of reactions, i.e., epoxide ring opening reactions, 1,4-conjugate addition reactions, and SN2 reactions in a regioselective manner. This review examines the applications of Gilman reagent in the total synthesis of both abundant and scarce natural products of remarkable synthetic pharmaceutical profile reported since 2011. The presented insights will be of a vital roadmap to general organic synthesis and it will contribute to the development of new natural products and their analogues in future drug discovery.

Recent Trends in the Petasis Reaction: A Review of Novel Catalytic Synthetic Approaches with Applications of the Petasis Reaction.

The Petasis reaction, also called the Petasis Borono-Mannich reaction, is a multicomponent reaction that couples a carbonyl derivative, an amine and boronic acids to yield substituted amines. The reaction proceeds efficiently in the presence or absence of a specific catalyst and solvent. By employing this reaction, a diverse range of chiral derivatives can easily be obtained, including α-amino acids. A broad substrate scope, high yields, distinct functional group tolerance and the availability of diverse catalytic systems constitute key features of this reaction. In this review article, attention has been drawn toward the recently reported methodologies for executing the Petasis reaction to produce structurally simple to complex aryl/allyl amino scaffolds.

Effects of Metal Ions and Substituents on HOMO-LUMO Gap Evident from UV-Visible and Fluorescence Spectra of Anthracene Derivatives.

Controlled intake of complex metal cations and anions in the human body and other biological systems is essential for the health and well-being of the environment. Anthracene and anthracene derivatives are the most widely used sensors for this purpose. Because of their convenience, better detection and results are preferred over colorimetric sensors, which offer better color detection by the naked eye. This review article will present different designs of chemosensors using fluorescence and UV-visible spectroscopy to determine different ions. Density functional theory and Austin model 1 are widely used for theoretical and computational studies of the energy levels of molecules. The Indo/Cis method is used to calculate the geometries of anthracene oligomers. A novel anthracene-based fluorescent probe containing the benzothiazole group BFA was highly sensitive and selective toward trivalent cations (Cr3+ and Fe3+). This sensor is not sensitive to other ions, including Aluminum trivalent ions. (N- ((anthracen-9-yl) methyl)-N-(pyridin-2-yl) pyridin-2-amine) has been designed to detect zinc and copper. Click chemistry using photodimerization can be used to form cellulose nanoparticles. TEMPO-mediated hypohalite oxidation converts hydroxyl groups to carboxylic groups. Amide linkage formation between amine and carboxylic acid was followed by the installation of an alkyne group. Copper (I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC) was used to produce highly photoresponsive and fluorescent cellulose nanoparticles by using coumarin, anthracene, and generated nanomaterials. The effects of naphthalene and phenanthrene on the spectra of anthracene were determined in a dilute solution. Temperature and solvent effects introduce different changes in fluorescence, emission, and absorption bands, leading to some changes in the configuration of anthracene. The solvent and temperature effects on variations of emission maxima of exciplex anthracene-diethylaniline (DEA) are also discussed.

Investigating the Use of Coumarin Derivatives as Lasers.

A benzene ring and a lactone ring combine to form the chemical coumarin. Dye lasers have made significant advances in laser technology. The coumarin molecule itself is a non-fluorescent but it displays high fluorescence when electron-denoting substituents such as sulfonamide, benzopyrone, amine, benzothiazole, hydroxyl, methoxy are substituted at various positions. Substituted coumarin possesses the highest energy properties, photostability, and alteration in electron mobility, and therefore could be effectively used as dye lasers. These are considered some of the best fluorophores due to their outstanding photophysical and photochemical properties, which include high fluorescence quantum yields, great photostability, good functionality, and a wide spectrum range. Various inorganic materials are used in classic laser technology to generate the necessary emission. Inorganic lasers come in various types and can emit light in the electromagnetic spectrum's ultraviolet, visible, or infrared parts. Inorganic lasers have certain limitations, which is why coumarin lasers are becoming increasingly popular due to their many advantages. Compared to inorganic lasers, dye lasers offer far better tunability and cover the entire visible and near-infrared range. They only emit at very few specific wavelengths and in extremely narrow bands. The property is therefore presented in this review.

Bacterial Tyrosinase Inhibition, Hemolytic and Thrombolytic Screening, and In Silico Modeling of Rationally Designed Tosyl Piperazine-Engrafted Dithiocarbamate Derivatives.

Piperazine is a privileged moiety that is a structural part of many clinical drugs. Piperazine-based scaffolds have attracted the attention of pharmaceutical and medicinal scientists to develop novel, efficient therapeutic agents owing to their significant and promising biological profile. In the current study, an ecofriendly ultrasonic-assisted synthetic approach was applied to achieve a novel series of 1-tosyl piperazine dithiocarbamate acetamide hybrids 4a-4j, which was evaluated for in vitro tyrosinase inhibition and thrombolytic and hemolytic cytotoxic activities. Among all the piperazine-based dithiocarbamate acetamide target molecules 4a-4j, the structural analogs 4d displayed excellent tyrosinase inhibition efficacy (IC50 = 6.88 ± 0.11 µM) which was better than the reference standard drugs kojic acid (30.34 ± 0.75 µM) and ascorbic acid (11.5 ± 1.00 µM), respectively, which was further confirmed by in silico induced-fit docking (IFD) simulation Good tyrosinase activities were exhibited by 4g (IC50 = 7.24 ± 0.15 µM), 4b (IC50 = 8.01 ± 0.11 µM) and 4c (IC50 = 8.1 ± 0.30 µM) dithiocarbamate acetamides, which were also better tyrosinase inhibitors than the reference drugs but were less active than the 4d structural hybrid. All the derivatives are less toxic, having values in the 0.29 ± 0.01% to 15.6 ± 0.5% range. The scaffold 4b demonstrated better hemolytic potential (0.29 ± 0.01%), while a remarkably high thrombolytic chemotherapeutic potential was displayed by analog 4e (67.3 ± 0.2%).

Effect of Substituents on Solubility, Medicinal, Absorption, Emission and Cationic/Anionic Detection Properties of Anthraquinone Derivatives.

Anthraquinones constitute an important class of compounds with wide applications. The solubility of derivatives at 298.15 K was discussed in ethanol-water solution and at atmospheric pressure, the solubility of 1-amino-4-hydroxy-9,10-anthraquinone (AHAQ) in binary solvents (ethanol-water combinations) was determined. Colour strength and fastening properties depend upon the kind and position of a hydrophobic group connected to the phenoxy ring of Anthraquinone moiety. There is a continuing interest in the creation of novel anthraquinone derivatives with biological activities since they have demonstrated potential for treating multiple sclerosis. For this purpose, by utilizing voltammetric and absorption studies, interactions of various derivatives with calf thymus DNA (ct-DNA) and the cationic surfactant cetyltrimethylammoniumbromide (CTAB) were examined. Here prominent Hydrophobic interaction and electron transfer resulting in binding to CTAB micelles were observed. The polarity index of the media was assessed and associated with the electrochemical parameters. The medicinal behaviour of Anthraquinone derivatives was a result of electron transfer reactions with DNA. UV-Visible and fluorescence properties were due to the transitions between n* and π* orbitals. Large absorption band with low dichroic ratio was characteristic of various derivatives of Anthraquinone. Presence of -NH group proves various derivatives remarkable calorimetric and anionic sensors.

Effect of Chloride, Sulfate, and Ferrate Salts on Electronic Energy Levels of Anthracene Proving it a Potential Candidate as an ON and ON-OFF UV-Vis Sensor.

Anthracene molecule possesses remarkable optical activity and till today this molecule is of special interest of scientists. Present study is focused on the study of effects of Chloride, Sulfate, Nitrate and Ferrate salts on absorption and emission spectra of targeted fluorophore in carbontetrachloride, chloroform, dichloromethane and methanol. Prominent solvatochromic effects shows dependence of HOMO-LUMO orbitals on solvent polarity. Anthracene molecules exhibits changes in absorption and emission spectra, and show both ON and ON-OFF behavior on addition of said ions. Based on experimental results it was concluded that fluorophore molecule could be used more effectively as UV-Visible (UV-V) sensors in comparison to the emission sensor.

Simmons-Smith Cyclopropanation: A Multifaceted Synthetic Protocol toward the Synthesis of Natural Products and Drugs: A Review.

Simmons-Smith cyclopropanation is a widely used reaction in organic synthesis for stereospecific conversion of alkenes into cyclopropane. The utility of this reaction can be realized by the fact that the cyclopropane motif is a privileged synthetic intermediate and a core structural unit of many biologically active natural compounds such as terpenoids, alkaloids, nucleosides, amino acids, fatty acids, polyketides and drugs. The modified form of Simmons-Smith cyclopropanation involves the employment of Et2Zn and CH2I2 (Furukawa reagent) toward the total synthesis of a variety of structurally complex natural products that possess broad range of biological activities including anticancer, antimicrobial and antiviral activities. This review aims to provide an intriguing glimpse of the Furukawa-modified Simmons-Smith cyclopropanation, within the year range of 2005 to 2022.

Investigation of boron-doped graphene oxide anchored with copper sulphide flowers as visible light active photocatalyst for methylene blue degradation.

The non-biodegradable nature of waste emitted from the agriculture and industrial sector contaminates freshwater reserves. Fabrication of highly effective and low-cost heterogeneous photocatalysts is crucial for sustainable wastewater treatment. The present research study aims to construct a novel photocatalyst using a facile ultrasonication-assisted hydrothermal method. Metal sulphides and doped carbon support materials work well to fabricate hybrid sunlight active systems that efficiently harness green energy and are eco-friendly. Boron-doped graphene oxide-supported copper sulphide nanocomposite was synthesized hydrothermally and was assessed for sunlight-assisted photocatalytic degradation of methylene blue dye. BGO/CuS was characterized through various techniques such as SEM-EDS, XRD, XPS, FTIR, BET, PL, and UV-Vis DRS spectroscopy. The bandgap of BGO-CuS was found to be 2.51 eV as evaluated through the tauc plot method. The enhanced dye degradation was obtained at optimum conditions of pH = 8, catalyst concentration (20 mg/100 mL for BGO-CuS), oxidant dose (10 mM for BGO-CuS), and optimum time of irradiation was 60 min. The novel boron-doped nanocomposite effectively degraded methylene blue up to 95% under sunlight. Holes and hydroxyl radicals were the key reactive species. Response surface methodology was used to analyze the interaction among several interacting parameters to remove dye methylene blue effectively.

The Corey-Seebach Reagent in the 21st Century: A Review.

The Corey-Seebach reagent plays an important role in organic synthesis because of its broad synthetic applications. The Corey-Seebach reagent is formed by the reaction of an aldehyde or a ketone with 1,3-propane-dithiol under acidic conditions, followed by deprotonation with n-butyllithium. A large variety of natural products (alkaloids, terpenoids, and polyketides) can be accessed successfully by utilizing this reagent. This review article focuses on the recent contributions (post-2006) of the Corey-Seebach reagent towards the total synthesis of natural products such as alkaloids (lycoplanine A, diterpenoid alkaloids, etc.), terpenoids (bisnorditerpene, totarol, etc.), polyketide (ambruticin J, biakamides, etc.), and heterocycles such as rodocaine and substituted pyridines, as well and their applications towards important organic synthesis.

Synthetic Potential of Regio- and Stereoselective Ring Expansion Reactions of Six-Membered Carbo- and Heterocyclic Ring Systems: A Review.

Ring expansion reactions fascinate synthetic chemists owing to their importance in synthesizing biologically active compounds and their efficacy in medicinal chemistry. The present review summarizes a number of synthetic methodologies, including stereoselective and regioselective pathways adopted by scientists, for framing medium- to large-size carbo- and heterocycles involving lactams, lactone, azepine and azulene derivatives via ring expansion of six-membered carbo- and heterocycles that have been reported from 2007-2022. Numerous rearrangement and cycloaddition reactions involving Tiffeneau-Demjanov rearrangement, Aza-Claisen rearrangement, Schmidt rearrangement, Beckmann rearrangement, etc., have been described in this regard.

Protease inhibition, in vitro antibacterial and IFD/MM-GBSA studies of ciprofloxacin-based acetanilides.

In this study, we have investigated ciprofloxacin-based acetanilides for their in-vitro inhibitory study against gram +ve, -ve bacteria and serine protease activity. The compounds 4e and 4g showed excellent antibacterial activity against Bacillus subtilis with a zone of inhibition (ZI) values of 40 ± 0.9 mm, 37 ± 1.4 mm and with MIC values of 4.0 ± 0.78 mg/mL, 3.0 ± 0.98 mg/ML respectively, while 4a and 4i were found most active against Escherichia coli, with ZI values 38 ± 0.1 mm, 46 ± 1.8 mm and with MIC values of 1.0 ± 0.25 mg/mL, 1.0 ± 0.23 mg/mL respectively. All derivatives (4a-j) significantly inhibited the catalytic activity of serine protease, while 4a exhibited a maximum (100%) inhibitory effect at 96 minutes having 22.50 minutes [Formula: see text], and non-competitive inhibition with 0.1±0.00µM Ki. The IFD/MM-GBSA studies highlighted the binding mode of 4a for protease inhibition and indicated improved binding affinity with -107.62 kcal/mol of ΔGbind.

Naphthalene and its Derivatives: Efficient Fluorescence Probes for Detecting and Imaging Purposes.

Naphthalene, white crystalline solid having polycyclic aromatic hydrocarbon with characteristic mothball order is naturally present in crucial oils of various plants. Naphthalene derivatives are extensive drug resources and are use as wetting agents, surfactants and as insecticides. These derivatives exhibit unique photo physical and chemical properties. These characteristics make them the most studied group of organic compounds. Naphthalene dyes have rigid plane and large π-electron conjugation. Therefor they have high quantum yield and excellent photostability. Naphthalene based fluorescence probes due to hydrophobic nature exhibit excellent sensing and selectivity properties towards anions and cations and also used as a part of target biomolecules. In conjugated probe system, introducing naphthalene moiety caused improvement in photo-stability. Therefore among various conjugated framework, naphthalene derivatives are considered excellent candidate for the construction of organic electronic appliances. These derivatives are useful for a variety of applications owing to their strong fluorescence, electroactivity and photostability. This article is based upon investigation of photophysical properties of naphthalene derivatives and fluorescence detecting probe of naphthalene. For photophysical properties the techniques under investigation are UV visible spectroscopy and fluorescence spectroscopy. Concentration dependent spectra and solvatochromic shifts on UV visible spectra are also part of discussion.

Study of Interactions Between 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine and Human DNA by Theoretical, Spectroscopic and Viscometric measurements.

From the last few years mode of interactions between drugs and DNA is an attractive research area as it bridges chemistry, molecular biology and medicinal science. Interactions between small heterocyclic molecules and human DNA is a noteworthy feature in pharmacology for investigation of drugs mechanism and designing of more effective and target specific drugs with fewer side effects. The present research work focuses on the theoretical investigations of 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine (SASA) by using Gaussian (16 W) software to predict optimized geometry, HOMO-LUMO gap, bond length, bond angle, dihedral angle, electronic and vibrational spectra. Possible reaction site observed in SASA was C7, C9 and C18 as these atoms show maximum charge density. Later the interactions of SASA with human DNA was explored spectroscopic investigations and viscometric investigations at physiological buffers of pH of 4.7 (stomach pH) and 7.4 (blood pH) respectively. Maximum absorbance between SASA-DNA complex was observed in buffer solution of pH 3.4 at wavelength of 370 nm, whereas at 7.4 has maximim absorbance between. Spectroscopic results reflects the bathochromic and hyperchromic shift succeeding the addition of human DNA. During viscosity measurement, intercalation and electrostatic mode of interaction were detected at low and high concentration of drug in solution respectively. Increase in the value of rate constant was observed with the increase in concentration of drug. Larger values of rate constant were observed at pH 7.4 in comparison to pH 3.5. Rate constant, thermodynamic parameters and viscometric analysis prefers the intake of SASA via blood.

Mixed micellar solubilization for procion blue MxR entrapment and optimization of necessary parameters for micellar enhanced ultrafiltration.

In this study, micellar enhanced ultrafiltration, MEUF, being an active methodology, has been employed to remove Procion Blue MxR (PBM) from synthetic effluent. MEUF is being applied to reduce the toxicity level of aqueous system using the micellar media of cationic surfactants i.e. Cetyl trimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC). Subsequently, the effect of addition of nonionic surfactant, Triton X-100 (TX-100), on solubilizing power of cationic surfactants is investigated. The values of partition coefficient and free energy of partition reflect the extent of interaction of the dye with the surfactants. Initially molecules of pollutants i.e. dye form ion pairs with ionic surfactants and, later on, the same is incorporated within micelle. Maximum value of free energy of partition ΔGp has been found to be -55.49 kJmol-1 and -50.43 kJmol in the presence of CPC and CTAB, respectively. The size of pollutant, thus, increases and, consequently, can be easily filtered. The effect of various factors i.e. concentration of surfactant, concentration of electrolyte (NaCl), transmembrane pressure, revolutions per minute (RPM) and pH, have been investigated to find the optimum conditions for maximum removal of PBM from aqueous system. The efficiency of MEUF has been assessed by calculating the values of rejection percentage and permeate flux. Both the surfactants were observed as strong candidates for PBM encapsulation but overall, maximum rejection percentage (R%) of 96.90% was attained by CPC.