Scaffolds In Medicinal Chemistry Research Articles

A review on synthesis of coumarin derived schiff’s base metal complexes and their control over E. coli bacterium

Nowadays, the dilemma of drug resistance to antibacterial strains is of huge concern. Among the bacteria, Escherchia coli (E. coli) is the major pathogen, which is found in human and other animals. It is responsible for variety of severe diseases. A variety of commonly used antibiotics such as amoxicillin, gentamycin, etc and fluid replacement method are the suggested treatments for the infections caused by E. coli. In a study, it was established that the metal-based heterocyclic drugs demonstrated a different mode of action compared to the commonly used heterocyclic antibacterial drugs. Coumarin, an oxaheterocycle, is a privileged scaffold in medicinal chemistry. Metal complexes of coumarin-derived Schiff’s bases exhibit a broad range of pharmacological activities. Therefore, in the present review article, we have focused on the synthesis of metal complexes of coumarin derived Schiff’s bases as well as their respective Schiff’s base ligands and their antibacterial activities against the gram-negative bacterium E. coli.

A ChemoEnzymatic Approach for the Preparation of “Linear‐Shaped” Diaryl Pyrazines as Potential Antiprotozoal Agents

AbstractNitrogenous heterocyclic rings are present in a wide range of drugs, natural compounds, and fine chemicals and are considered privileged scaffolds in medicinal chemistry. Seeking novel anti‐protozoal drugs acting on new targets or by novel mechanisms of action, we focused on a preliminary evaluation of the potential of “linear‐shaped” diaryl pyrazines. To this purpose, a two‐enzyme chemoenzymatic synthesis of this heteroaromatic core was carried out. Specifically, starting from simple, commercially available aromatic aldehydes, the target pyrazines were obtained through a sequence of biocatalytic benzoin condensation, chemical oxidation and a transaminase‐mediated tandem process of transamination and cyclization. The profiles of the compounds as antiprotozoal agents were evaluated in vitro against parasites cultures of the Leishmania and Plasmodium genera and using the human cell line HepG2.

Pyrazole Scaffold: Potential PTP1B Inhibitors for Diabetes Treatment.

The overexpression of the Protein Tyrosine Phosphatase 1B (PTP1B), a key role in the development of insulin resistance, diabetes (T2DM) and obesity, seems to have a substantial impact as a negative regulator of the insulin and leptin signaling pathways. Therefore, inhibiting PTP1B is a prospective therapeutic approach for the treatment of diabetes and obesity. However, the pyrazole scaffold is expected to be of significant pharmaceutical interest due to its broad spectrum of pharmacological actions. This study aims to focus on the significance of pyrazole scaffold in medicinal chemistry, the impact of PTP1B in diabetes and the therapeutic approach of pyrazole scaffold to treat T2DM. A comprehensive analysis of the published literature in several pharmaceutical and medical databases, such as the Web of Science (WoS), PubMed, ResearchGate, ScienceDirect etc., were indeed successfully completed and classified accordingly. Results: As reviewed, the various derivatives of the pyrazole scaffold exhibited prominent PTP1B inhibitory activity. The result showed that derivatives of oxadiazole and dibenzyl amine, chloro substituents, 1, 3-diaryl pyrazole derivatives with rhodanine-3-alkanoic acid groups, naphthalene and also 1, 3, 5-triazine-1H-pyrazole-triazolothiadiazole derivatives, octyl and tetradecyl derivative, indole- and N-phenylpyrazole-glycyrrhetinic acid derivatives with trifluoromethyl group, 2,3-pyrazole ring-substituted-4,4-dimethyl lithocholic acid derivatives with 4- fluoro phenyl substituted and additional benzene ring in the pyrazole scaffold significantly inhibits PTP1B. In silico study observed that pyrazole scaffold interacted with amino acid residues like TYR46, ASP48, PHE182, TYR46, ALA217 and ILE219. Diabetes is a metabolic disorder that elevates the risk of mortality and severe complications. PTP1B is a crucial component in the management of diabetes and obesity. As a result, PTP1B is a promising therapeutic target for the treatment of T2DM and obesity in humans. We concluded that the pyrazole scaffold has prominent inhibitory potential against PTP1B.

A Review on Synthetic Thiazole Derivatives as an Antimalarial Agent.

Thiazole is a widely studied core structure in heterocyclic chemistry and has proven to be a valuable scaffold in medicinal chemistry. The presence of thiazole in both naturally occurring and synthetic pharmacologically active compounds demonstrates the adaptability of these derivatives. The current study attempted to review and compile the contributions of numerous researchers over the last 20 years to the medicinal importance of these scaffolds, with a primary focus on antimalarial activity. The review is based on an extensive search of PubMed, Google Scholar, Elsevier, and other renowned journal sites for a thorough literature survey involving various research and review articles. A comprehensive review of the antimalarial activity of the thiazole scaffold revealed potential therapeutic targets in Plasmodium species. Furthermore, the correlation of structure-activity-relationship (SAR) studies from various articles suggests that the thiazole ring has therapeutic potential. This article intends to point researchers in the right direction for developing potential thiazole-based compounds as antimalarial agents in the future.

Fluorescent 2-carbonyl carbazole ketones: Photophysical properties, molecular structure and selective detection of Fe3+ ion

Owing to the diverse implication of carbazole scaffolds in medicinal chemistry, photoelectronic materials and chromophores, the molecules containing the carbazole motif have attracted significant attention over the years. In this work, the vibronic contributions to carbazole structures could facilely change the solvatochromic effect, absorption wavelength, emission wavelength, and Stokes shifts of six 2-carbonyl carbazole ketones fluorophores. Among them, the structure of 1-(1-methyl-9H-carbazol-2-yl)ethanone (3a) were confirmed from single crystal XRD studies. The ratiometric detection of Fe(III) ion of 2-carbonyl carbazole ketone 3a were investigated. Furthermore, it was speculated that chemosensor 3a toward the recognition of Fe3+ cation was dependent on its rigid structure and good coplanarity of the conjugated system, strong intramolecular charge-transfer of 3a.

Review on advancements of pyranopyrazole: synthetic routes and their medicinal applications.

Pyranopyrazoles are among the most distinguished, biologically potent, and exciting scaffolds in medicinal chemistry and drug discovery. Synthesis and design of pyranopyrazoles using functional modifications via multicomponent reactions (MCRs) are thoroughly found in synthetic protocols by forming new C-C, C-N, and C-O bonds. This review aims to focus on the biological importance of pyranopyrazoles as well as on a diverse synthetic approach for their synthesis using various catalytic systems such as acid-catalyzed, base-catalyzed, ionic liquids and green media-catalyzed, nano-particle-catalyzed, metal oxide-supported catalysts, and silica-supported catalysts. In this review, we have summarized data on the advancements in synthesizing pyranopyrazole from the last two decades to the mid-2023 and research papers describing the importance of these scaffolds. This review will be significant for synthetic organic chemists and researchers working in organic chemistry.

Recent advances in the synthesis and medicinal perspective of pyrazole-based α-amylase inhibitors as antidiabetic agents.

Diabetes is a serioushealth threat across the globe, claiming millions of lives worldwide. Among the various strategies employed, inhibition of α-amylase is a therapeutic protocol for the management ofType 2 diabetes mellitus. α-Amylase is a crucial enzyme involved in the breakdown of dietary starch into simpler units. However, the clinically used α-amylase inhibitors have various drawbacks. Therefore, design and development of novel α-amylase inhibitors have gained significant attention. The pyrazole motif has been identified as a versatile scaffold in medicinal chemistry, and recent studies have led to the identification of various pyrazole-based α-amylase inhibitors. This review compiles therapeutic implications of pyrazole-appended α-amylase inhibitors; their synthesis, biological activities, structure-activity relationships and molecular docking studies are discussed.

LED-induced Ru-photoredox Pd-catalyzed C-H arylation of (6-phenylpyridin-2-yl)pyrimidines and heteroaryl counterparts.

N-heterocycles are essential building blocks and scaffolds in medicinal chemistry. A Pd-catalyzed, Ru-photoredox-mediated C-H arylation is applied herein, for converting a series of functionality-inclusive (6-phenylpyridin-2-yl)pyrimidines to single arylated derivatives, using phenyldiazonium tetrafluoroborate as aryl source. This green chemistry-compliant transformation is induced by LED light. The drug-like modular substrates are constructed via combination of Biginelli multi-component condensation and Suzuki C-C cross-coupling, in order to strategically install, adjacent to the Ph-ring intended to undergo C-H arylation, a (6-pyridin-2-yl)pyrimidine that plays the role of a chelating directing moiety for the C-H arylation catalyst. The scope has been demonstrated on a series of 26 substrates, comprising diverse Ph-ring substituents and substitution patterns, as well as with 13 different aryl donors. Substrates in which the Ph-ring (arylation acceptor) was replaced by an electron-rich heteroaryl counterpart (2-/3-thiophene or -benzofuran) have also been examined and found to undergo arylation regioselectively. End-product conformations afford interesting motifs for occupying 3D chemical space, as implied by single-crystal X-ray diffraction, which has allowed the elucidation of six structures of aryl derivatives and one of an unprecedented pyrimidine-pyridine-benzofuran carbopalladated complex, believed to be a C-H activation derivative.

Insight into Indole‐Based Heterocyclic Scaffolds: A Medicinal Chemistry Perspective

AbstractThe importance of indole‐based heterocycle scaffolds in medicinal chemistry has increased as a result of their significant pharmacological and biological characteristics. These compounds′ importance in the discovery and creation of cutting‐edge medications to treat a variety of diseases is an instance of their worth. The current study highlights the numerous methods available to create different indole‐based heterocycle scaffolds and their favourable medical uses with the literature that has been published up to 2023.

Synthesis and in Silico Studies of Some New 1,2,3-Triazolyltetrazole Bearing Indazole Derivatives as Potent Antimicrobial Agents.

1,2,3-Triazole and tetrazole derivatives bearing pyrrolidines are found to exhibit notable biological activity and have become useful scaffolds in medicinal chemistry for application in lead discovery and optimization. Novel indazole bearing 1,2,3-triazolyltetrazoles were designed as potential antimicrobial candidates. The structure of duel heterocyclics was validated by a spectroscopic technique of infrared (IR), nuclear magnetic resonance (1 H and 13 C NMR), and mass spectral data. Compounds 4b, 4c, 4d, and 4h were found to have a stronger antibacterial effect against Gram-positive (S. aureus, B. subtilis, M. Luteus) and Gram-negative (E. coli, P. aeruginosa) microorganisms with MICs ranging from 5±0.03-18±0.02 μM, respectively. Moreover, scaffolds 4a, 4h showed potent antifungal activity against A. flavus, M. gypsuem strains with MIC values of 10±0.02, 11±0.01 μM, which are similar activity that of the standard Itraconazole (MIC=8±0.02, 10±0.01 μM). The binding mode for compound 4 inside the catalytic pocket of S. aureus complexed with nicotinamide adenine dinucleotide phosphate and trimethoprim and produced a network of hydrophobic and hydrophilic interactions (3FRE). From in silico results, 4b demonstrated highly stable hydrogen binding amino acids Leu62(X) [N18…O, 2.47 Å], Arg44(X) [N17…N, 3.11 Å], Thr96(X) [N10…OG1, 3.05 Å], Gly94(X) [F7…N, 2.82 Å], and Gly43(X) [F7…N, 2.90 Å], which are plays a crucial role in ensuring efficient binding of the ligand in a crystal structure of antibacterial receptor. Furthermore, the physicochemical and ADME filtration molecular properties, estimation of toxicity, and bioactivity scores of these novel scaffolds were evaluated by using SwissADME and ADMETlab2.0 online protocols. Thus, the significant antimicrobial activity of indazole linked to duel heterocyclic compounds can be used for development of new antimicrobial agents with further modifications.

CsPbBr3 Perovskite Nanocrystals for Photocatalytic [3+2] Cycloaddition.

Visible-light-induced halide-exchange between halide perovskite and organohalide solvents has been studied in which photoinduced electron transfer from CsPbBr3 nanocrystals (NCs) to dihalomethane solvent molecules produces halide anions via reductive dissociation, followed by a spontaneous anion-exchange. Photogenerated holes in this process are less focused. Here, for CsPbBr3 in dibromomethane (DBM), we discover that Br radical (Br⋅) is a key intermediate resulting from the hole oxidation. We successfully trapped Br⋅ with reported methods and found that Br⋅ is continuously generated in DBM under visible light irradiation, hence imperative for catalytic reaction design. Continuous Br⋅ formation within this halide-exchange process is active for photocatalytic [3+2] cycloaddition for vinylcyclopentane synthesis, a privileged scaffold in medicinal chemistry, with good yield and rationalized diastereoselectivity. The NC photocatalyst is highly recyclable due to Br-based self-healing, leading to a particularly economic and neat heterogeneous reaction where the solvent DBM also acts as a co-catalyst in perovskite photocatalysis. Halide perovskites, notable for efficient solar energy conversion, are demonstrated as exceptional photocatalysts for Br radical-mediated [3+2] cycloaddition. We envisage such perovskite-induced Br radical strategy may serve as a powerful chemical tool for developing valuable halogen radical-involved reactions.

Synthetic Routes and Pharmacological Activities of Purine Derivatives: A Review

Abstract: The Purine moiety is regarded as the ubiquitous nitrogen-containing heterocycle in nature and is recognized as a privileged scaffold in medicinal chemistry. Moreover, the purine derivatives are heterocyclic aromatic compounds consisting of conjoined pyrimidine and imidazole moieties. Purine derivatives are involved in various metabolic processes as cofactors associated with a wide variety of enzymes and receptors. Therefore, many synthetic ways to obtain purine derivatives were developed using different reagents such as pyrimidine, imidazole, and some acyclic precursors. This article review focuses on the synthetic methodologies of purine derivatives from its first synthesis in the 19th century to this last decade and also reports a variety of proven pharmacological applications for the purine derivatives. This review offers a panoply of synthetic routes that medicinal and organic chemistry researchers can use in the preparation and design of new purine derivatives.

Flexibility in the bridge of chalcone derivatives is important for the inhibition of cellular growth

Chalcones and their derivatives are a privileged scaffold in medicinal chemistry, demonstrating numerous biological activities. These molecules have shown significant potential toward the development of novel cancer therapies. While much is known about modification to the chalcone aryl rings, little is known about conformations of the bridge between the aryl rings. Here we report the synthesis and biological evaluation of a series of molecules with flexible and rigid bridge conformations. Crystal structures of a select group of molecules were determined. Flexibility in the chalcone bridge containing the enone moiety was determined to be important for activity. Screening in three distinct cancer cell lines showed significant differences in the activity between the flexible and rigid conformations. Crystal structures suggest an increase in bond rotation and weakened π-bonding in the flexible chalcone bridge, which may contribute to the stronger anti-proliferative activity.

A Review on the Synthesis and Anticancer Potentials of Imidazothiazole Derivatives.

Cancer is one of the severe diseases in which abnormal cells divide and proliferate in an uncontrolled manner without any regulation. Globally cancer is among the leading causes of death; according to a recent report of by the WHO, around 10 million people died in 2018 due to cancer. It has also been reported that by 2040, approximately 30 million new cases will be reported every year. The increase in the incidences of cancer is taking a toll on the health care system worldwide. Considerable scientific literature is available on anticancer agents but newer therapeutic strategies are still required in this field to address novel approaches to drug design and discovery to counter this problem. Imidazothiazole represents a privileged scaffold in medicinal chemistry and provides the medicinal chemist the possibility to modulate the physiochemical properties of the lead compound. In recent times, imidazothiazole scaffold is broadly explored for its anticancer activity, which acts through various mechanisms such as EGFR, B-RAF, DHFR kinase inhibition and tubulin polymerization inhibition and other molecular mechanisms of action. Due to their feasible synthetic accessibility and promising pharmacological profile, it has attracted various medicinal chemists to explore and develop imidazothiazole derivatives as potent and safe anticancer agents. In the present article, we have reviewed various potent imidazothiazole scaffold-based derivatives reported as anticancer agents, their synthetic strategies, Structure Activity Relationship (SAR), mechanism of action, and molecular docking along with their future perspective. This review will be very useful for medicinal chemists for drug design and development of imidazothiazole-based potent antiproliferative agents.

Synthetic approaches to cis-THC, a promising scaffold in medicinal chemistry

The chemistry of phytocannabinoids has witnessed renewed interest these last decades as a consequence of reduced restrictions, research on the endocannabinoid system and the development of approved therapeutic treatments based on cannabinoids. The medicinal cannabinoid market constitutes a prolific scenario in current medicine. Most studies, however, have focused on only two major components of Cannabis sativa L., namely, cannabidiol (CBD, 2) and (−)-Δ9-trans-tetrahydrocannabinol (Δ9-trans-THC, 6a), the latter being the main psychoactive compound of this plant. The cis-diastereoisomer of Δ9-trans-THC, Δ9-cis-THC, although also present in the same plant, has been less investigated in terms of biological, medicinal and synthetic perspectives. Interestingly, the cis-fused tetrahydrobenzo [c]chromene motif present in Δ9-cis-THC is embedded in many other natural products which also exhibit interesting biological activities such as anticancer, antifungal, and antiparasitic. This review discloses synthetic approaches that have been established towards the cis-fused tetrahydroisochromene system of Δ9-cis-THC.

Pyridazinic Bioisosteres with Potential Applications in Medicinal Chemistry and Agriculture

Bioisosteres are substituents or groups (atoms, ions, or molecules) with similar chemical or physical properties, and which usually have similar biological properties. Pyridazine and its derivatives are invaluable scaffolds in medicinal chemistry, having a large variety of activities such as antibacterial, antifungal, antimalarial, anticancer, antituberculosis, antihypertensive, etc. Also, the pyridazine core is of high interest in agriculture, being used as a growth factor for plants, herbicides, etc. This study aims to review our previous contributions related to antimicrobials and the germination and seedling capabilities of some seeds and plants of some pyridazine classical and nonclassical bioisosteres. So, we present herein the synthesis (under conventional thermal heating and microwave irradiation) and spectral characterization of seven series of pyridazine bioisosteres, the in vitro antimicrobial activity (against different strains of Gram-positive and Gram-negative bacteria and fungi), and the biologic effect on wheat germination and seedling growth. Some pyridazine bioisosteres proved to have very good activity against pathogenic bacterial strains, with some spectacular results. Overall, nonclassical bioisosteres prove to have better antibacterial and antifungal activity compared with classical bioisosteres. The pyridazine bioisosteres may influence the wheat germination rate, seedling growth, height, and weight of the plantlets. Feasible explanations for this behaviour were furnished.

Silver(I)-Catalyzed Synthesis of Cuneanes from Cubanes and their Investigation as Isosteres.

Bridged or caged polycyclic hydrocarbons have rigid structures that project substituents into precise regions of 3D space, making them attractive as linking groups in materials science and as building blocks for medicinal chemistry. The efficient synthesis of new or underexplored classes of such compounds is, therefore, an important objective. Herein, we describe the silver(I)-catalyzed rearrangement of 1,4-disubstituted cubanes to cuneanes, which are strained hydrocarbons that have not received much attention since they were first described in 1970. The synthesis of 2,6-disubstituted or 1,3-disubstituted cuneanes can be achieved with high regioselectivities, with the regioselectivity being dependent on the electronic character of the cubane substituents. A preliminary assessment of cuneanes as scaffolds for medicinal chemistry suggests cuneanes could serve as isosteric replacements of trans-1,4-disubstituted cyclohexanes and 1,3-disubstituted benzenes. An analogue of the anticancer drug sonidegib was synthesized, in which the 1,2,3-trisubstituted benzene was replaced with a 1,3-disubstituted cuneane.

Pd‐Catalyzed Arylation and Benzylation of Tyrosine at the δ−C(sp2)−H and C(2) Positions: Expanding the Library of Unnatural Tyrosines

AbstractThis paper describes Pd(II)‐catalyzed picolinamide‐directed intermolecular arylation and benzylation of remote δ−C(sp2)−H bond (C(2) position) of the aryl ring in tyrosine derivatives and expansion of the library of unnatural tyrosine. Various racemic and enantiopure bis C(2) (ortho C−H) arylated and benzylated tyrosine derivatives were assembled in good yields. Removal of the picolinoyl moiety after the C(2)−H arylation and assembling of tyrosine‐based peptides using C(2)−H arylated tyrosines were shown. Tyrosine derivatives and biaryl amino acids are vital scaffolds in medicinal chemistry. Correspondingly, this work is a contribution towards the expansion of the unnatural tyrosine library with biaryl‐ or terphenyl and diarylmethane‐based tyrosine scaffolds.

Indol-3-ylglyoxylamide as Privileged Scaffold in Medicinal Chemistry.

In recent years, indolylglyoxylamide-based derivatives have received much attention due to their application in drug design and discovery, leading to the development of a wide array of compounds that have shown a variety of pharmacological activities. Combining the indole nucleus, already validated as a "privileged structure," with the glyoxylamide function allowed for an excellent template to be obtained that is suitable to a great number of structural modifications aimed at permitting interaction with specific molecular targets and producing desirable therapeutic effects. The present review provides insight into how medicinal chemists have elegantly exploited the indolylglyoxylamide moiety to obtain potentially useful drugs, with a particular focus on compounds exhibiting activity in in vivo models or reaching clinical trials. All in all, this information provides exciting new perspectives on existing data that can be useful in further design of indolylglyoxylamide-based molecules with interesting pharmacological profiles. The aim of this report is to present an update of collection data dealing with the employment of this moiety in the rational design of compounds that are able to interact with a specific target, referring to the last 20 years.

Pyridine derivatives as preferable scaffolds for the process of discovering new drugs

The pyridine ring is present in numerous significant plant compounds. It is used as a therapeutic to boost the solubility and bioavailability of less soluble chemicals since it is a polar and ionizable aromatic molecule. Chemical compounds derived from pyridine are highly sought-after in the pharmaceutical industry. An essential synthesis strategy in the search for novel medications is the fusion of the pyridine nucleus. Due to the compounds’ powerful therapeutic characteristics, medicinal chemists have long been fascinated by the chemistry of pyridine and its derivatives, which inspires them to look for and make novel compounds with biological utility. There are significant ramifications for medical chemistry in the adaptability of pyridine and its derivatives as reactants and starting materials for structural changes. Pesticides and agricultural chemicals that heavily rely on pyridine derivatives include insecticides, fungicides, and herbicides; However, this page focuses on their medical applications. Pyridine derivatives are frequently used in the textile industry to create dyes. We present the most recent findings from 2010 onward, highlighting the growing significance of pyridine scaffolds in medicinal chemistry and the development of new drugs. Even though there are a lot of studies on pyridine derivatives, this chapter only has compounds with a clear pharmacophore.