Search Results (173)

Background/Objectives: Protein kinases play a crucial role in cancer initiation, progression, and therapeutic resistance by regulating signalling pathways involved in tumour growth and survival. Consequently, they represent major targets in anticancer drug discovery. Among heterocyclic scaffolds explored in kinase inhibitor design, benzimidazole has emerged as a privileged structure due to its strong hydrogen-bonding capability and structural resemblance to purine moieties. Triazole motifs are also widely incorporated into bioactive molecules because of their metabolic stability, favourable electronic properties, and ability to establish key interactions within kinase active sites. This review aims to summarise and critically discuss benzimidazole- and triazole-based kinase inhibitors, both as individual scaffolds and as hybrid systems, with emphasis on their kinase targets and multitarget potential. Methods: The relevant literature was surveyed from major scientific databases focusing on studies describing the synthesis, biological evaluation, and molecular modelling of benzimidazole- and triazole-containing kinase inhibitors. Results: Numerous studies demonstrate that both benzimidazole and triazole scaffolds exhibit significant kinase inhibitory activity against oncogenic targets, including EGFR, cyclin-dependent kinases (CDKs), and components of the PI3K/Akt/mTOR signalling pathway. Hybrid molecules combining these pharmacophores frequently enhance binding interactions and facilitate the development of multitarget kinase inhibitors. Structure–activity relationship trends indicate that pharmacophore accessibility, substitution patterns, and linker architecture influence inhibitory potency and selectivity. Conclusions: Overall, benzimidazole- and triazole-based scaffolds represent promising platforms for developing next-generation multitarget anticancer agents and provide valuable insights for the rational design of improved kinase inhibitors. Full article

Pyrrolo[2,3-d]pyrimidine is a privileged fused heterocyclic scaffold that has attracted considerable attention in medicinal chemistry due to its diverse biological activities. Herein, we report an efficient synthesis strategy for the preparation of the pyrrolo[2,3-d]pyrimidine-based natural toyocamycin aglycone and pyrrolo[2,3-d]pyrimidine derivatives. The synthesis of toyocamycin aglycone features a key benzylamine nucleophilic substitution followed by a palladium-catalyzed cyanation reaction. From a key intermediate derived from this route, nineteen new pyrrolo[2,3-d]pyrimidine derivatives were rapidly synthesized via key Suzuki–Miyaura coupling and amine nucleophilic substitution reactions. Their cytotoxic activities were evaluated against Huh-7 and HepG liver cancer cell lines. Most derivatives were inactive after 24 h. However, 28a–28c, 28e and 28f exhibited moderate cytotoxicity with IC₅₀ values ranging from 5.7 to 62.6 μM. Among them, compound 28e displayed the highest potency against HepG cells, with IC₅₀ values of 5.7 μM. Compared with normal HEK293 cells, it showed a selectivity index (SI) of 3.60 against HepG cells. Preliminary structure-activity relationship analysis suggested that incorporation of a cyclopropyl group further improves antitumor activity. Full article

Azobenzene derivatives constitute a prototypical class of photoresponsive molecular switches with broad utility in synthetic chemistry and biomedical research, owing to their distinctive physicochemical properties. Recent molecular engineering has enabled red-shifted photoisomerization into the visible biological window, thereby enhancing tissue penetration and reducing phototoxicity. This review systematically surveys contemporary advances in azobenzene-based photoswitchable systems with a specific focus on medicinal chemistry and photopharmacology. Emphasis is placed on rational design strategies—including ortho-functionalization, heteroaryl substitution, and bridged diazocine scaffolds—that improve photophysical properties, thermal stability, and photostationary state distributions. Particular attention is devoted to the integration of these novel azobenzene motifs as privileged pharmacophores, highlighting their emerging therapeutic applications in neurological modulation, enzyme inhibition, receptor targeting, and oncology, as well as their translational potential in drug discovery and photodynamic therapy. Full article

The discovery of novel anti-infective agents is a continuous challenge in medicinal chemistry, particularly due to the rise in resistant fungal and viral strains. Within this context, the biphenyl subunit has been identified as a highly versatile privileged structure capable of interacting with diverse protein targets via hydrophobic and π-interactions. The purpose of this study is to review the pharmacological potential of biphenyl-based compounds, focusing on their application as anti-infective agents. We comprehensively analyzed recent literature and rational design strategies concerning biphenyl derivatives, examining structure-activity relationships, molecular docking insights, and structural optimizations aimed at enhancing both pharmacodynamics and pharmacokinetics. The reviewed studies demonstrate that incorporating biphenyl moieties yields compounds with potent antifungal and antiviral activities. Specifically, optimized biphenyl derivatives exhibit strong inhibitory effects against resistant Candida strains and crucial viral targets, including mutant variants of the HIV-1 reverse transcriptase and protease enzymes. Furthermore, strategic modifications, such as scaffold hopping and the introduction of specific substituents, successfully mitigated cytotoxicity and improved metabolic stability against cytochrome P450 enzymes. Biphenyl serves as a robust and adaptable scaffold for drug design. Its rational structural optimization provides a viable pathway to overcome drug resistance and develop effective, metabolically stable anti-infective therapeutics. Full article

Tetrahydrocarbazole (THCz) is a privileged scaffold validated by clinically approved drugs such as ondansetron, frovatriptan, and ramatroban and exhibits diverse bioactivities including antimicrobial, antitumor, antidiabetic, and neuroprotective effects. Despite extensive structure–activity relationship (SAR) studies, a systematic integration of findings across different therapeutic targets has been lacking. This review provides a comprehensive SAR dissection of THCz derivatives across key targets (bacterial sliding clamp, BTK, HDAC, AMPK, etc.), analyzing how modifications at key positions of the core scaffold (N-9, C-1, and C-6) influence potency and selectivity. Notably, we highlight four emerging design paradigms: pharmacophore hybridization, conformational constraint, cross-target SAR decoding, and precision intervention. By consolidating fragmented knowledge into a practical cross-target SAR matrix, this review offers a strategic framework for the rational design of next-generation THCz-based therapeutics. Full article

Background: Inhibition of histone deacetylase is a highly sought-after objective in the fight against cancer. Thus, the development of innovative HDAC inhibitors with significantly higher potency than SAHA against specific cancer cell types represents complex and demanding work. Method: The utilization of the underexplored and privileged scaffold 4-chlorothieno[2,3-b]pyridine as a cap tethering diverse aliphatic and aromatic linkers, followed by the screening of both cellular and enzymatic activities, is undertaken in this study. Results: Compounds 7a and 9a demonstrated impressive mean GI₅₀ values of 2.15 µM and 1.89 µM, respectively. Both compounds reduced caspase-3 levels in RPMI-8226 cells, suggesting induction of apoptosis. Compound 7a showed remarkable IC₅₀ values of 0.37 µM, 0.58 µM, and 0.70 µM against HDACs 1, 4, and 6, respectively, consistent with the cellular assay. Additionally, compound 7a exhibited a selectivity index of 11 for RPMI-8226 cells over PBMCs, reflecting its high selectivity and potential safety. Moreover, ADMET prediction tools indicated that compounds 7a and 9b may have more favorable pharmacokinetic properties than the gold-standard HDAC inhibitor, SAHA. Conclusions: Further study and exploration of the derivatives of compounds 7a and 9a can lead to further advancement in the development of potent HDAC inhibitor anticancer drugs. Full article

Naphthyridine derivatives have emerged as privileged scaffolds with diverse pharmacological activities, particularly in anticancer and antiviral drug discovery. In this study, a series of naphthyridine-based derivatives (1–10b) was designed, synthesized, and structurally characterized using IR, ¹H/¹³C NMR, and mass spectrometry, and evaluated as dual-function antiproliferative and anti-fowlpox virus agents supported by integrated computational analyses. The synthesized compounds were screened for in vitro antiproliferative activity against HeLa, HCT-116, and MCF-7 cancer cell lines, as well as normal WI-38 lung fibroblasts. Several derivatives exhibited potent cytotoxic activity with enhanced selectivity toward cancer cells. Compound 5b showed the highest activity against HeLa cells, compound 1 was most effective against HCT-116 cells, while compounds 7 and 8 displayed remarkable activity against MCF-7 cells, with compound 7 surpassing doxorubicin and compound 8 demonstrating excellent selectivity toward normal cells. Mechanistic investigations revealed that compounds 7 and 8 acted as dual topoisomerase I/IIβ inhibitors, inducing G2/M cell cycle arrest and intrinsic apoptosis associated with caspase-9 activation and downregulation of topoisomerase II protein expression. Selected derivatives were further evaluated for antiviral activity against fowlpox virus using in ovo and in vivo SPF embryonated chicken egg models, where compounds 2 and 9a exhibited the highest therapeutic indices, comparable to ribavirin, and compound 9a markedly suppressed viral replication and titers in vivo. ADMET profiling, molecular docking, molecular dynamics simulations, and DFT calculations supported the experimental findings and identified compound 10a as the most favorable theoretical candidate. Overall, this integrated experimental–computational approach establishes naphthyridine derivatives as a rationally designed multifunctional chemotype for simultaneous anticancer and antiviral drug development. Full article

Axially chiral compounds, indispensable in asymmetric catalysis, drug discovery, and materials science, have witnessed transformative advancements in synthesis through organocatalytic kinetic resolution (OKR) over the past decade. This review systematically dissects the latest achievements (2010–2025) in OKR, focusing on catalyst design, mechanistic insights, substrate diversification, and synthetic applications across C–C biaryl, C–N heterobiaryl, and olefinic axially chiral frameworks. By harnessing non-covalent interactions, OKR has emerged as a powerful strategy to overcome the challenges of low rotational barriers and limited stereocontrol, offering sustainable and enantioselective access to privileged chiral scaffolds. Furthermore, the current challenges and future prospects in this rapidly evolving field are assessed. Full article

Hydantoins, exemplified by the imidazolidine-2,4-dione core, are privileged scaffolds in medicinal chemistry due to their compact structure, versatile hydrogen-bonding capacity, ability to fine-tune physicochemical properties for drug-like molecules, and potential to engage a diverse array of biological targets. This review highlights major advances in hydantoin-based drug discovery since 2019, emphasizing their evolving applications in oncology; neurology; infectious diseases; and cardiovascular, metabolic, and immune disorders. Recent studies demonstrate their success as kinase inhibitors, androgen receptor antagonists, and metalloprotease inhibitors, and emerging roles in modulating sterol isomerase, glycogen synthase kinase-3β, and ADAMTS family enzymes. Novel hybrid scaffolds—such as catechol–hydantoins, β-carboline–hydantoins, and spirocyclic thiohydantoins—have yielded potent and selective anticancer and antiviral leads. The discovery of BAY-9835 and GLPG1972 underscores the clinical potential of hydantoin-based metalloproteinase inhibitors in cardiovascular and osteoarthritic conditions. Furthermore, new antimicrobial, antimalarial, and antileishmanial derivatives illustrate the scaffold’s capacity to address multidrug resistance and neglected tropical diseases. Advances in computational design, stereochemical optimization, and hybridization strategies have expanded the structural and functional diversity of hydantoins, enhancing their target selectivity and pharmacokinetic profiles. Overall, hydantoins and their analogs remain at the forefront of small-molecule drug discovery, offering rich prospects for therapeutic innovation in diverse disease areas. Full article

A DABCO-catalyzed one-pot synthesis of a novel pentacyclic heterocycle featuring an unprecedented benzo[4,5]imidazo[1,2-a]chromeno[3,2-e]pyridine scaffold from 2-(cyanomethyl)benzimidazole and 3-trifluoroacetyl-4-phenyl-4H-chromene has been developed. This hybrid architecture merges three privileged pharmacophores—benzimidazole, chromene, and pyridine—into a rigid, nearly planar π-extended system decorated with trifluoromethyl and nitrile groups. The structure of 8-phenyl-13a-(trifluoromethyl)-13aH-benzo[4,5]imidazo[1,2-a]chromeno[3,2-e]pyridine-6-carbonitrile was unambiguously confirmed through NMR spectroscopy and X-ray diffraction analysis. A plausible mechanism involves Michael addition, hemiaminal formation, ring opening, recyclization, and oxidation. Full article

Michael acceptors, such as chalcones and benzylidenes, are privileged scaffolds for the development of anticancer agents. Taking this into account, we developed a selective Claisen–Schmidt condensation of the dammarane-type triterpenoid hollongdione with pyridine-2-carbaldehyde, enabling controlled synthesis of mono- and bis-substituted triterpenes depending on the reaction conditions. The reaction demonstrated high temperature-dependent regioselectivity, providing C2-mono- 2 or 2,21-bis-substituted 3 triterpenes with yields up to 96% and 95%, respectively. The structures of the newly synthesized triterpene chalcones were elucidated by 1D and 2D NMR spectroscopy and unambiguously confirmed by a single-crystal X-ray diffraction, which established the E configuration of the exocyclic double bond. In biological studies, the bis-2-pyridylidene derivative 3 exhibited a pronounced and broad-spectrum antitumor activity in the NCI-60 panel, inducing cell death in 58 of 59 cancer cell lines. High selectivity toward melanoma, renal, and prostate cancer cell lines was observed, with selectivity indices (SI) of up to 18.82 for melanoma LOX IMVI. In MTT assays, compound 3 displayed a submicromolar cytotoxicity, particularly against the KRAS-mutant PANC-1 cell line (IC₅₀ = 0.22 µM). Anticancer activity was further confirmed in a zebrafish (Danio rerio) xenograft model of human HCT116 colon cancer, where tumor growth inhibition reached 72% without pronounced embryotoxicity (LC₅₀ = 1.4 µM). We have developed an efficient approach for the site-selective modification of hollongdione, providing access to potent anticancer dammarane-type chalcones. The bis-2-pyridylidene derivative 3 emerged as a promising lead compound, demonstrating submicromolar potency, high selectivity towards melanoma, and significant in vivo efficacy in a zebrafish xenograft model. Full article

Enzymatic cascades, defined here as multi-enzymatic sequences operating on a shared reaction pathway and inspired by the spatial and temporal organization of metabolism, have emerged as powerful and versatile tools for sustainable organic synthesis. They minimize intermediate isolation, enhance atom economy and ensure outstanding chemo-, regio- and stereoselectivity, providing efficient alternatives to conventional multistep routes. Here, we highlight the conceptual role of substrate channeling, minimal cells, artificial metabolism and enzyme promiscuity in the translation of enzymatic cascades into synthetic strategies. Special attention is focused on advanced immobilization on functional and renewable supports, which enhance stability and recyclability and introduce new ways for thermodynamic and kinetic control. Hybrid systems integrating enzymes with photocatalysis, electrochemistry and chemical modules expand the catalytic repertoire far beyond biology. Complementary tools in bioinformatics, structural modeling and artificial intelligence may also enable pathway balancing, predictive design and dynamic optimization. Applications span from the valorization of renewable feedstocks to the synthesis of privileged scaffolds and fine chemicals. Full article

The concept of “Smart Secondary Metabolites” is introduced here to describe a privileged class of natural products defined by structural originality, biosynthetic adaptability, and broad interaction potential with biological systems. Elatol, a halogenated sesquiterpene chiefly produced by Laurencia red seaweeds and occasionally accumulated by their consumers, exemplifies this concept with remarkable clarity. Its biosynthesis unfolds from farnesyl diphosphate via γ-bisabolane cations, bromochlorination, and stereoselective cyclization to chamigrene scaffolds, generating both (+)- and (–)-enantiomers, two metabolites with clearly distinct potential ecological roles and pharmacological profiles. This review synthesizes the current state of knowledge on elatol’s distribution, biosynthetic origins, ecological relevance, and therapeutic potential. Elatol serves as a multifunctional chemical mediator, fulfilling defensive, communicative, and regulatory roles whose intensity shifts in response to herbivory, biofouling, temperature, and salinity. In parallel, its potent activities against infectious, metabolic, and neoplastic diseases highlight its growing value as a drug lead, reflected in a rising number of patent claims. Altogether, elatol emerges as a model Smart Secondary Metabolite whose ecological sophistication and biochemical versatility position it as a promising scaffold for marine-derived drug discovery. Full article

The indole scaffold represents a privileged structural motif in medicinal chemistry, celebrated for its remarkable chemical versatility, biological ubiquity, and clinical relevance. This review provides a comprehensive analysis of the recent research on the indole nucleus, emphasizing its physicochemical properties, reactivity patterns, and capacity to interact with a wide array of biological targets. Found in key endogenous compounds such as serotonin and melatonin, indole serves as a cornerstone in neurochemical signaling, circadian regulation, and chrono-metabolic homeostasis. Beyond its physiological roles, synthetic indole derivatives have shown extensive therapeutic potential across diverse domains, including oncology, infectious diseases, neurodegenerative disorders, immunomodulation, and metabolic syndromes. The review explores structure–activity relationships (SAR), pharmacokinetics, and the molecular mechanisms by which indole-based compounds exert their tremendous effects, that are ranging from enzyme inhibition to receptor modulation. Special focus is given to current clinical applications and emerging strategies for enhancing drug specificity, bioavailability, and safety through indolic frameworks. Additionally, we highlight the translational potential of indole-containing molecules in personalized medicine, underscoring opportunities for future drug discovery. By integrating insights from medicinal chemistry, biochemistry, pharmacology, and clinical science, this review affirms the indole ring’s enduring value as a central scaffold in therapeutic innovation. Full article

Naturally inspired electrophilic scaffolds, such as chalcone, curcumin, aurone, C-5-monocarbonyl-curcumin, and bis-(arylidene)piperidone, are considered privileged structures because of their ability to interact with a variety of biological macromolecules, including receptors and enzymes. They thus serve as versatile platforms for drug discovery efforts aimed at developing structurally related analogues endowed with improved bioactivity. Five-membered nitrogen-based heterocycles, such as triazole and pyrazole, have been widely used in medicinal chemistry both as templates and spacers for the design of bioactive compounds; they indeed provide the advantage of enhancing favourable interactions with the target, while also improving solubility and bioavailability, along with reducing toxicity. This review reports the latest advances in the development of hybrids incorporating the above classes of synthons acting as potential anticancer chemotherapeutics and provides a critical summary of the design strategies that have guided the development of antitumor agents. Full article