Recent applications of 1,3-thiazole core structure in the identification of new lead compounds and drug discovery

Electrochemical Enaminone-Thioamide Annulation and Thioamide Dimeric Annulation for the Tunable Synthesis of Thiazoles and 1,2,4-Thiadiazole

A green and sustainable electrochemical oxidative cyclization of enaminones with thioamides under metal- and oxidant-free conditions has been developed, providing an efficient approach for thiazole synthesis. Furthermore, 1,2,4-thiadiazoles can be selectively accessed via the electrochemical dimerization of thioamides in the absence of enaminones.

Anticancer Potential of the S-Heterocyclic Ring Containing Drugs and its Bioactivation to Reactive Metabolites

Sulfur-containing heterocyclic derivatives have been disclosed for binding with a wide range of cancer-specific protein targets. Various interesting derivatives of sulfur-containing heterocyclics such as benzothiazole, thiazole, thiophene, thiazolidinedione, benzothiophene, and phenothiazine, etc have been shown to inhibit diverse signaling pathways implicated in cancer. Significant progress has also been made in molecular targeted therapy against specific enzymes such as kinase receptors due to potential binding interactions inside the ATP pocket. Sulfur-containing heterocyclic ring metal complexes i. e., benzothiazole, thiazole, thiophene, benzothiophene and phenothiazines are among the most promising active anticancer compounds. However, sulfur heteroaromatic rings, particularly thiophene, are of high structural alert due to their metabolism to reactive metabolites. The mere presence of a structural alert itself does not determine compound toxicity therefore, this review focuses on some specific findings that shed light on factors influencing the toxicity. In the current review, synthetic strategies of introducing the sulfur core ring in the synthesized derivatives are discussed with their structure-activity relationships to enhance our understanding of toxicity mechanisms and develop safer therapeutic options. The sulfur-containing marketed anticancer drugs included in this review direct the synthesis of novel compounds and will help in the development of potent, safer sulfur-based anticancer drugs in near future.

An efficient synthesis of mono-, di-, and tri-substituted 1,3-thiazoles employing functionalized thioamides as thiocarbonyl precursors

Herein, we report an efficient strategy to synthesize functionalized 1,3-thiazoles using alkyl 2-amino-2-thioxoacetates. Thioamides, the synthetic precursors, react effortlessly with electrophilic reagents and are transformed into a series of phenyl-, methyl-, and acyl-substituted thiazoles with high functionalization at the 2nd position through sequential C-S/C-N bond formation. Rapid reaction times under metal-free mild conditions is a noteworthy feature of the reported protocol. Given the intriguing biological significance of the synthesized molecules, we further performed a comprehensive evaluation of their potency against the SARS-CoV-2 receptor (PDB ID: 7mc6) using a molecular docking approach, with binding scores ranging from -4.3 to -8.2 kcal mol-1.

Synthesis, antifungal evaluation, two-dimensional quantitative structure-activity relationship and molecular docking studies of isoxazole derivatives as potential fungicides

BACKGROUND

Sheath blight and bakanae disease, prominent among emerging rice ailments, exert a profound impact on rice productivity, causing severe impediments to crop yield. Excessive use of older fungicides may lead to the development of resistance in the pathogen. Indeed, a pressing and immediate need exists for novel, low-toxicity and highly selective fungicides that can effectively combat resistant fungal strains.

RESULTS

A series of 20 isoxazole derivatives were synthesized using alkoxy/halo acetophenones and N,N-dimethylformamidedimethylacetal. These compounds were characterized by various spectroscopic techniques, namely 1H nuclear magnetic resonance (NMR), 13C NMR and liquid chromatography-high-resolution mass spectrometry, and were evaluated for their fungicidal activity against Rhizoctonia solani and Fusarium fujikuroi. Compound 5n (5-(2-chlorophenyl) isoxazole) exhibited highest activity (effective dose for 50% inhibition [ED50] = 4.43 μg mL-1) against R. solani, while 5p (5-(2,4-dichloro-2-hydroxylphenyl) isoxazole) exhibited highest activity (ED50 = 6.7 μg mL-1) against F. fujikuroi. Two-dimensional quantitative structural-activity relationship (QSAR) analysis, particularly multiple linear regression (MLR) (Model 1), highlighted chi6chain and DistTopo as the key descriptors influencing fungicidal activity. Molecular docking studies revealed the potential of these isoxazole derivatives as novel fungicides targeting sterol 14α-demethylase enzyme, suggesting their importance as crucial intermediates for the development of novel and effective fungicides.

CONCLUSION

All test compounds were effective in inhibiting both fungi, according to the QSAR model, with various descriptors, such as structural, molecular shape analysis, electronic and thermodynamic, playing an important role. Molecular docking studies confirmed that these compounds can potentially replace commercially available fungicides and help control fungal pathogens in rice crops effectively. © 2024 Society of Chemical Industry.

Microwave-Assisted One-Pot Telescoped Synthesis of 2-Amino-1,3-thiazoles, Selenazoles, Imidazo[1,2-a]pyridines, and Other Heterocycles from Alcohols

Primary and secondary alcohols have been converted into 2-amino-1,3-thiazoles under microwave irradiation, employing trichloroisocyanuric acid (TCCA) as a dual oxidant and chlorine source, TEMPO as a co-oxidant, and thiourea. Secondary alcohols underwent a single-stage, one-pot conversion process, while primary alcohols required a two-stage, one-pot procedure. Both transformations were completed within minutes (25-45 min). The versatility of this protocol extends to the synthesis of other heterocycles, including 1,3-selenazoles, 2-aminoimidazoles, imidazo[1,2-a]pyridines, quinoxalines, and hydrazino thiazoles by replacing thiourea with the appropriate surrogates.

Glucose regulation by newly synthesized boronic acid functionalized molecules as dipeptidyl peptidase IV inhibitor: a potential compound for therapeutic intervention in hyperglycaemia

Management of type 2 diabetes mellitus (T2DM) using dipeptidyl peptidase IV (DPP IV) inhibitors is gaining precedence as this enzyme plays an indispensable role in cleaving and inactivating peptides, such as glucagon-like peptide-1 (GLP-1), incretin hormones, and glucose-dependent insulinotropic polypeptide (GIP). There are several DPP IV inhibitors used to treat T2DM, but limited by side effects such as disturbed GIT, flu-like symptoms, etc. Thus, there is an urgent need for the development of novel and better DPP IV inhibitors for the management of the same. In the present study, we investigated the effect of new boronic acid-based thiazole compounds as DPP IV inhibitors. We used substituted anilines that were progressively modified through a multi-step synthesis and then chemically characterised. These molecules have good binding affinity and molecular interactions at the active site of the DPP IV enzyme. Two boronic acid-based molecules, i.e. PC06R58 and PC06R108, were used for the assessment of their in-vitro enzymatic activities. Both molecules (PC06108 and PC06R58) exhibited potent uncompetitive DPP IV enzyme inhibition at two different concentrations of 90.9 and 15.6 nM, respectively, compared to sitagliptin having an IC50 of 17.3 nM. Furthermore, the oral glucose tolerance test suggested significantly reduced blood glucose levels at 20 mg/kg of the body weight upon administration of PC06R58 and PC06R108 molecules in rats after glucose ingestion (2 g/kg of the body weight). The compounds showed satisfactory DPP IV inhibition. Furthermore, DPP IV inhibitory activity and acceptable pre-ADME/Tox profile indicate it is a lead compound in this novel class of DPP IV inhibitors.Communicated by Ramaswamy H. Sarma.

Emerging green synthetic routes for thiazole and its derivatives: Current perspectives

This review article provides an overview of the green synthesis of thiazole derivatives, emphasizing sustainable and environmentally friendly methodologies. Thiazole derivatives possess significant value and find diverse applications across various fields. However, conventional synthesis methods often involve hazardous reagents and generate substantial waste, posing environmental concerns. The green synthesis of thiazole derivatives employs renewable starting materials, nontoxic catalysts, and mild reaction conditions to minimize environmental impact. Innovative techniques such as microwave irradiation, ultrasound synthesis, green solvents, a green catalyst-based approach, and mechanochemistry-mediated synthesis are employed, offering advantages in terms of scalability, cost-effectiveness, and purification simplicity. The resulting thiazole derivatives exhibit comparable or enhanced biological activities, showcasing the feasibility and practicality of green synthesis in drug discovery. This review paper underscores the importance of sustainable approaches in functional molecular synthesis and encourages further research in this domain.

Quinoline-based thiazolyl-hydrazones target cancer cells through autophagy inhibition

Heterocyclic pharmacophores such as thiazole and quinoline rings have a significant role in medicinal chemistry. They are considered privileged structures since they constitute several Food and Drug Administration (FDA)-approved drugs for cancer treatment. Herein, we report the synthesis, in silico evaluation of the ADMET profiles, and in vitro investigation of the anticancer activity of a series of novel thiazolyl-hydrazones based on the 8-quinoline (1a-c), 2-quinoline (2a-c), and 8-hydroxy-2-quinolyl moiety (3a-c). The panel of several human cancer cell lines and the nontumorigenic human embryonic kidney cell line HEK-293 were used to evaluate the compound-mediated in vitro anticancer activities, leading to [2-(2-(quinolyl-8-ol-2-ylmethylene)hydrazinyl)]-4-(4-methoxyphenyl)-1,3-thiazole (3c) as the most promising compound. The study revealed that 3c blocks the cell-cycle progression of a human colon cancer cell line (HCT-116) in the S phase and induces DNA double-strand breaks. Also, our findings demonstrate that 3c accumulates in lysosomes, ultimately leading to the cell death of the hepatocellular carcinoma cell line (Hep-G2) and HCT-116 cells, by the mechanism of autophagy inhibition.

Investigation of new 1,2,3-triazolyl-quinolinyl-propan-2-ol derivatives as potential antimicrobial agents: in vitro and in silico approach

A new series of 1-((1-(4-substituted benzyl)-1H-1,2,3-triazol-4-yl)methoxy)-2-(2-substituted quinolin-4-yl)propan-2-ol (9a-x) have been synthesized. The newly synthesized 1,2,3-triazolyl-quinolinyl-propan-2-ol (9a-x) derivatives were screened for in vitro antimicrobial activity against M. tuberculosis H37Rv, E. coli, P. mirabilis, B. subtilis, and S. albus. Most of the compounds showed good to moderate antibacterial activity and all derivatives have shown excellent to good antitubercular activity with MIC 0.8-12.5 μg/mL. To know the plausible mode of action for antibacterial activity the docking study against DNA gyrase from M. tuberculosis and S. aureus was investigated. The compounds have shown significant docking scores in the range of -9.532 to -7.087 and -9.543 to -6.621 Kcal/mol with the DNA gyrase enzyme of S. aureus (PDB ID: 2XCT) and M. tuberculosis (PDB ID: 5BS8), respectively. Against the S. aureus and M. tuberculosis H37Rv strains, the compound 9 l showed good activity with MIC values of 62.5 and 3.33 μM. It also showed significant docking scores in both targets with -8.291 and -8.885 Kcal/mol, respectively. Molecular dynamics was studied to investigate the structural and dynamics transitions at the atomistic level in S. aureus DNA gyrase (2XCT) and M. tuberculosis DNA gyrase (5BS8). The results revealed that the residues in the active binding pockets of the S. aureus and M. tuberculosis DNA gyrase proteins that interacted with compound 9 l remained relatively consistent throughout the MD simulations and thus, reflected the conformation stability of the respective complexes. Thus, the significant antimicrobial activity of derivatives 9a-x recommended that these compounds could assist in the development of lead compounds to treat for bacterial infections.Communicated by Ramaswamy H. Sarma.

Synthesis, in vitro potency of inhibition, enzyme kinetics and in silico studies of quinoline-based α-glucosidase inhibitors

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target α-glucosidase, which catalyzes starch hydrolysis in the intestine. In an attempt to find potential α-glucosidase inhibitors, a series of twenty new quinoline linked benzothiazole hybrids (8a-t) were synthesized in good yields from suitable reaction procedures and their chemical structures were analyzed by 1HNMR, 13CNMR, IR, and ESI-MS analysis. The synthesized derivatives further screened for their activity against α-glucosidase. Among them, compounds 8b, 8h, 8n and 8o exhibited remarkable α-glucosidase inhibitory activity with IC50 values ranging from 38.2 ± 0.3 to 79.9 ± 1.2 µM compared with standard drug acarbose (IC50 = 750.0 ± 2.0 µM). Enzyme kinetic studies of the most active compound (8h) indicated a non-competitive inhibition with Ki value of 38.2 µM. Moreover, the homology modeling, molecular docking and molecular dynamics simulation studies were conducted to reveal key interactions between the most active compound 8h and the targeted enzyme. These results are complementary to the experimental observations. In order to predict the druggability of the novel derivatives, the pharmacokinetic properties were also applied. These findings could be useful for the design and development of new α-glucosidase inhibitors.

A Review on the Mechanism and Structure-activity Relationship of Resveratrol Heteroaryl Analogues

Resveratrol is one of the most interesting naturally-occurring nonflavonoid phenolic compounds with various biological activities, such as anticancer, neuroprotection, antibacterial, and anti-inflammatory. However, there is no clinical usage of resveratrol due to either its poor activity or poor pharmacokinetic properties. Heteroarenes-modified resveratrol is one pathway to improve its biological activities and bioavailability, and form more modification sites. In this review, we present the progress of heteroaryl analogues of resveratrol with promising biological activities in the latest five years, ranging from the synthesis to the structure-activity relationship and mechanism of actions. Finally, introducing heteroarenes into resveratrol is an effective strategy, which focuses on the selectivity of structure-activity relationship in vivo.

Thiazole, Isatin and Phthalimide Derivatives Tested in vivo against Cancer Models: A Literature Review of the Last Six Years

BACKGROUND

Cancer is a disease characterized by the abnormal multiplication of cells and is the second leading cause of death in the world. The search for new effective and safe anticancer compounds is ongoing due to factors such as low selectivity, high toxicity, and multidrug resistance. Thus, heterocyclic compounds derived from isatin, thiazole and phthalimide that have achieved promising in vitro anticancer activity have been tested in vivo and in clinical trials.

OBJECTIVE

This review focused on the compilation of promising data from thiazole, isatin, and phthalimide derivatives, reported in the literature between 2015 and 2022, with in vivo anticancer activity and clinical trials.

METHODS

A bibliographic search was carried out in the PUBMED, MEDLINE, ELSEVIER, and CAPES PERIODIC databases, selecting relevant works for each pharmacophoric group with in vivo antitumor activity in the last 6 years.

RESULTS

In our study, 68 articles that fit the scope were selected and critically analyzed. These articles were organized considering the type of antitumor activity and their year of publication. Some compounds reported here demonstrated potent antitumor activity against several tumor types.

CONCLUSION

This review allowed us to highlight works that reported promising structures for the treatment of various cancer types and also demonstrated that the privileged structures thiazole, isatin and phthalimide are important in the design of new syntheses and molecular optimization of compounds with antitumor activity.

Identification of a 2-phenylthiazole derivative acetylcholinesterase modulator with in vitro antitumor activity in breast cancer cells

Acetylcholinesterase (AchE) is a serine hydrolase with classical function to degrade acetylcholine and terminate neurotransmission. While "nonclassical" functions of AchE were involved in cell growth, death, invasion, etc. The expression and activity of AchE is changed in tumors, suggesting AChE inhibitors (AchEIs) may serve as potential antitumor drugs. In this study, the antitumor activity of a series of 2-phenylthiazole derivatives originally designed and synthesized as AchEIs were investigated. One compound named A6, was screened out with superior antitumor efficacy, especially against breast cancer MCF-7 cells. A6 significantly disrupted the amino acid metabolism and inhibited migration of MCF-7. In addition, A6 induced apoptosis of MCF-7 cells. To clarify how A6 affected on MCF-7 cells, RNA-seq analysis was conducted to evaluate the whole genome effect of A6 on gene expression. A total of 153 genes were increased, and the expression of 81 genes was decreased. GO and KEGG enrichment analysis showed A6 treatment mainly disrupted sterol/cholesterol pathway, Ras signaling pathway, VEGF signaling pathway, etc. Moreover, bioinformatic analysis and cell viability test showed A6 plays anticancer role by regulating Best1 and HIST1H2BJ. These results indicate that AchEI A6 could be a potential antitumor agent for breast cancer patients and could help the development of novel therapies.

Podophyllotoxin: Recent Advances in the Development of Hybridization Strategies to Enhance Its Antitumoral Profile

Podophyllotoxin is a naturally occurring cyclolignan isolated from rhizomes of Podophyllum sp. In the clinic, it is used mainly as an antiviral; however, its antitumor activity is even more interesting. While podophyllotoxin possesses severe side effects that limit its development as an anticancer agent, nevertheless, it has become a good lead compound for the synthesis of derivatives with fewer side effects and better selectivity. Several examples, such as etoposide, highlight the potential of this natural product for chemomodulation in the search for new antitumor agents. This review focuses on the recent chemical modifications (2017-mid-2023) of the podophyllotoxin skeleton performed mainly at the C-ring (but also at the lactone D-ring and at the trimethoxyphenyl E-ring) together with their biological properties. Special emphasis is placed on hybrids or conjugates with other natural products (either primary or secondary metabolites) and other molecules (heterocycles, benzoheterocycles, synthetic drugs, and other moieties) that contribute to improved podophyllotoxin bioactivity. In fact, hybridization has been a good strategy to design podophyllotoxin derivatives with enhanced bioactivity. The way in which the two components are joined (directly or through spacers) was also considered for the organization of this review. This comprehensive perspective is presented with the aim of guiding the medicinal chemistry community in the design of new podophyllotoxin-based drugs with improved anticancer properties.

Design, synthesis, and biological evaluation of thiazole/thiadiazole carboxamide scaffold-based derivatives as potential c-Met kinase inhibitors for cancer treatment

As part of our continuous efforts to discover novel c-Met inhibitors as antitumor agents, four series of thiazole/thiadiazole carboxamide-derived analogues were designed, synthesised, and evaluated for the in vitro activity against c-Met and four human cancer cell lines. After five cycles of optimisation on structure-activity relationship, compound 51am was found to be the most promising inhibitor in both biochemical and cellular assays. Moreover, 51am exhibited potency against several c-Met mutants. Mechanistically, 51am not only induced cell cycle arrest and apoptosis in MKN-45 cells but also inhibited c-Met phosphorylation in the cell and cell-free systems. It also exhibited a good pharmacokinetic profile in BALB/c mice. Furthermore, the binding mode of 51am with both c-Met and VEGFR-2 provided novel insights for the discovery of selective c-Met inhibitors. Taken together, these results indicate that 51am could be an antitumor candidate meriting further development.

The Synthesis, In Vitro Bio-Evaluation, and In Silico Molecular Docking Studies of Pyrazoline-Thiazole Hybrid Analogues as Promising Anti-α-Glucosidase and Anti-Urease Agents

In the present work, a concise library of benzothiazole-derived pyrazoline-based thiazole (1-17) was designed and synthesized by employing a multistep reaction strategy. The newly synthesized compounds were screened for their α-glucosidase and urease inhibitory activities. The scaffolds (1-17) were characterized using a combination of several spectroscopic techniques, including FT-IR, 1H-NMR, 13C-NMR, and EI-MS. The majority of the synthesized compounds demonstrated a notable potency against α-glucosidase and urease enzymes. These analogues disclosed varying degrees of α-glucosidase and urease inhibitory activities, with their IC50 values ranging from 2.50 to 17.50 μM (α-glucosidase) and 14.30 to 41.50 (urease). Compounds 6, 7, 14, and 12, with IC50 values of 2.50, 3.20, 3.40, and 3.50 μM as compared to standard acarbose (IC50 = 5.30 µM), while the same compounds showed 14.30, 19.20, 21.80, and 22.30 comparable with thiourea (IC50 = 31.40 μM), respectively, showed excellent inhibitory activity. The structure-activity relationship revealed that the size and electron-donating or electron-withdrawing effects of substituents influenced the enzymatic activities such as α-glucosidase and urease. Compound 6 was a dual potent inhibitor against α-glucosidase and urease due to the presence of -CF3 electron-withdrawing functionality on the phenyl ring. To the best of our knowledge, these synthetic compounds were found to be the most potent dual inhibitors of α-glucosidase and urease with minimum IC50 values. Moreover, in silico studies on most active compounds, i.e., 6, 7, 14, and 12, were also performed to understand the binding interaction of most active compounds with active sites of α-glucosidase and urease enzymes.

2-Amino Thiazole Derivatives as Prospective Aurora Kinase Inhibitors against Breast Cancer: QSAR, ADMET Prediction, Molecular Docking, and Molecular Dynamic Simulation Studies

The aurora kinase is a key enzyme that is implicated in tumor growth. Research revealed that small molecules that target aurora kinase have beneficial effects as anticancer agents. In the present study, in order to identify potential antibreast cancer agents with aurora kinase inhibitory activity, we employed QSARINS software to perform the quantitative structure-activity relationship (QSAR). The statistical values resulted from the study include R2 = 0.8902, CCCtr = 0.7580, Q2 LOO = 0.7875, Q2LMO = 0.7624, CCCcv = 0.7535, R2ext = 0.8735, and CCCext = 0.8783. Among the four generated models, the two best models encompass five important variables, including PSA, EstateVSA5, MoRSEP3, MATSp5, and RDFC24. The parameters including the atomic volume, atomic charges, and Sanderson's electronegativity played an important role in designing newer lead compounds. Based on the above data, we have designed six series of compounds including 1a-e, 2a-e, 3a-e, 4a-e, 5a-e, and 6a-e. All these compounds were subjected to molecular docking studies by using AutoDock v4.2.6 against the aurora kinase protein (1MQ4). Among the above 30 compounds, the 2-amino thiazole derivatives 1a, 2a, 3e, 4d, 5d, and 6d have excellent binding interactions with the active site of 1MQ4. Compound 1a had the highest docking score (-9.67) and hence was additionally subjected to molecular dynamic simulation investigations for 100 ns. The stable binding of compound 1a with 1MQ4 was verified by RMSD, RMSF, RoG, H-bond, molecular mechanics-generalized Born surface area (MM-GBSA), free binding energy calculations, and solvent-accessible surface area (SASA) analyses. Furthermore, newly designed compound 1a exhibited excellent ADMET properties. Based on the above findings, we propose that the designed compound 1a may be utilized as the best theoretical lead for future experimental research of selective inhibition of aurora kinase, therefore assisting in the creation of new antibreast cancer drugs.

Vetting of New 2,5-Bis (2,2,2-trifluoroethoxy) Phenyl-Linked 1,3-Thiazolidine-4-one Derivatives as AURKA and VEGFR-2 Inhibitor Antiglioma Agents Assisted with In Vitro and In Silico Studies

The bioactivity of 1,3-thiazolidin-4-one derivatives with a 2,5-bis (2,2,2-trifluoroethoxy) phenyl moiety was computationally developed and evaluated. All of the synthesized thiazolidin-4-one derivatives have their chemical structures characterized using a variety of methods, including nuclear magnetic resonance (NMR) (1H and 13C), high-resolution mass spectrometry (HRMS), and Fourier transform infrared (FTIR) radiation. A human glioblastoma cancer cell line (LN229) was used to investigate the purified derivatives' antiglioma cancer efficacy. By using the MTT, colony formation, and tunnel tests, respectively, the in vitro cytotoxic and apoptotic effects of these compounds were assessed. Thiazolidin-4-one derivatives 5b, 5c, and 5e were discovered to have the best efficacy against glioblastoma cells out of all of these compounds. The derivatives 5b, 5c, and 5e were determined to have respective IC50 values of 9.48, 12.16, and 6.43 g/mL. Computation results showed that the bioactivity evaluations of the compounds were quite significant. The bridging -NH group forms a hydrogen bond with Glu 260 of synthesized derivatives 5b, 5c, 5d, 5e, and 5h. The vast majority of freshly developed compounds obeyed Lipinski's rule of five, which is in line with the results that the ADMET model predicted. Additionally, molecular docking evaluation and molecular dynamics simulation investigations against the proteins AURKA and VEGFR-2 were conducted for the synthesized compounds to incorporate both in silico and in vitro data. The findings revealed that almost all of the compounds had considerable binding to AURKA and VEGFR-2 residues, with binding affinities ranging from -9.8 to -7.9 kcal/mol. Consequently, the results of the biological investigations and the docking scores demonstrated that thiazolidinone molecule 5e containing 4-chlorophenyl substituent may be considered as a potential moiety for glioblastoma cancer treatments.

The Role of Five-Membered Heterocycles in the Molecular Structure of Antibacterial Drugs Used in Therapy

Five-membered heterocycles are essential structural components in various antibacterial drugs; the physicochemical properties of a five-membered heterocycle can play a crucial role in determining the biological activity of an antibacterial drug. These properties can affect the drug's activity spectrum, potency, and pharmacokinetic and toxicological properties. Using scientific databases, we identified and discussed the antibacterials used in therapy, containing five-membered heterocycles in their molecular structure. The identified five-membered heterocycles used in antibacterial design contain one to four heteroatoms (nitrogen, oxygen, and sulfur). Antibacterials containing five-membered heterocycles were discussed, highlighting the biological properties imprinted by the targeted heterocycle. In some antibacterials, heterocycles with five atoms are pharmacophores responsible for their specific antibacterial activity. As pharmacophores, these heterocycles help design new medicinal molecules, improving their potency and selectivity and comprehending the structure-activity relationship of antibiotics. Unfortunately, particular heterocycles can also affect the drug's potential toxicity. The review extensively presents the most successful five-atom heterocycles used to design antibacterial essential medicines. Understanding and optimizing the intrinsic characteristics of a five-membered heterocycle can help the development of antibacterial drugs with improved activity, pharmacokinetic profile, and safety.

New Thiophenyl-pyrazolyl-thiazole Hybrids as DHFR Inhibitors: Design, Synthesis, Antimicrobial Evaluation, Molecular Modeling, and Biodistribution Studies

The antibiotic resistance problems constitute a considerable threat to human health worldwide; thus, the discovery of new antimicrobial candidates to conquer this issue is an imperative requirement. From this view, new thiophenyl-pyrazolyl-thiazole hybrids 3-10 were synthesized and screened for their antibacterial efficiency versus Gram - and Gram + bacterial strains compared to the reference drug amoxicillin. It was noticed that the new hybrids displayed significant antibacterial efficacy versus Gram - bacteria, especially against Pseudomonas aeruginosa. Also, all the screened candidates demonstrated a noticeable antifungal effect against Candida albicans (MICs = 3.9-125 μg/mL) relative to fluconazole (MIC = 250 μg/mL). Moreover, the new hybrids were investigated for their antituberculosis potency against Mycobacterium tuberculosis (RCMB 010126). Derivatives 4c, 6b, 8b, 9b, and 10b demonstrated prominent antituberculosis efficiency (MICs = 0.12-1.95 μg/mL) compared with the reference drug isoniazid (MIC = 0.12 μg/mL). The latter derivatives were further assessed for their inhibitory potency versus M. tuberculosis DHFR enzyme. The compounds 4c, 6b and 10b presented a remarkable suppression effect with IC50 values of 4.21, 5.70, and 10.59 μM, respectively, compared to that of trimethoprim (IC50 = 6.23 μM). Furthermore, biodistribution profile using radiolabeling way revealed a perceived uptake of 131I-compound 6b into infection induced models. The docking study for the new hybrids 4c, 6b, 8b, 9b and 10b was performed to illustrate the various binding modes with Mtb DHFR enzyme. In silico ADMET studies for the most potent inhibitors 4c, 6b and 10b were also accomplished to predict their pharmacokinetic and physicochemical features.

Design, Synthesis, Anticancer Evaluation and Molecular Modeling Studies of New Thiazolidinone-Benzoate Scaffold as EGFR Inhibitors, Cell Cycle Interruption and Apoptosis Inducers in HepG2

Synthesis of new anticancer candidates with protein kinases inhibitory potency is a major goal of pharmaceutical science and synthetic research. This current work represents the synthesis of a series of substituted benzoate-thiazolidinones. Most prepared thiazolidinones were evaluated in vitro for their potential anticancer activity against three cell lines by MTT assay, and they found to be more effective against cancer cell lines with no harm toward normal cells. Thiazolidinones 5 c and 5 h were further evaluated to be kinase inhibitors against EGFR showing effective inhibitory impact (with IC50 value; 0.2±0.009 and 0.098±0.004 μM, for 5 c and 5 h, respectively). Furthermore, 5 c and 5 h have effects on cell cycle and apoptosis induction capability in HepG2 cell lines by DNA-flow cytometry analysis and annexin V-FITC apoptosis assay, respectively. The results showed that they have effect of disrupting the cell cycle and causing cell mortality by apoptosis in the treated cells. Moreover, molecular docking studies showed better binding patterns for 5 c and 5 h with the active site of the epidermal growth factor receptor (EGFR) protein kinase (PDB code 1M17). Finally, toxicity risk and physicochemical characterization by Osiris method was performed on most of the compounds, revealing excellent properties as possible drugs.

Synthesis, Antioxidant, and Antifungal Activities of β-Ionone Thiazolylhydrazone Derivatives and Their Application in Anti-Browning of Freshly Cut Potato

In order to develop a new type of antioxidants with high efficiency, a series of β-ionone thiazolylhydrazone derivatives were designed and synthesized from β-ionone, and their structures were characterized by 1H-NMR, 13C-NMR, FT-IR, and HR-MS. The antioxidant test in vitro indicated that most of the target compounds had high biological activity. Among them, compound 1k exhibited very strong DPPH (1,1-diphenyl-2-picrylhydrazyl radical)-scavenging activity with a half-maximal effective concentration (IC50) of 86.525 μM. Furthermore, in the ABTS (2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt)-scavenging experiment, compound 1m exhibited excellent activity with an IC50 of 65.408 μM. Their biological activities were significantly better than those of the positive control Trolox. These two compounds, which have good free-radical-scavenging activity in vitro, were used as representative compounds in the anti-browning experiment of fresh-cut potatoes. The results showed that 1k and 1m had the same anti-browning ability as kojic acid, and they were effective browning inhibitors. In addition, it is well known that microbial infection is one of the reasons for food oxidation. Therefore, we investigated the antifungal activity of 25 target compounds against eight plant fungi at a concentration of 125 mg/L. The results indicated that these compounds all have some antifungal activity and may become new potential fungicides. Notably, compound 1u showed the best inhibitory effect against Poria vaporaria, with an inhibition rate as high as 77.71%; it is expected to become the dominant structure for the development of new antifungal agents.

Molecular dynamics simulation approach of hybrid chalcone-thiazole complex derivatives for DNA gyrase B inhibition: lead generation

Compounds bearing thiazole and chalcone groups have been reported to be excellent leads for antibacterial, antitubercular and anticancer activities. In view of this, we performed quantitative structure-activity relationship studies using QSARINS for dataset preparation and for developing validated QSAR models that can predict novel series of thiazole-chalcone hybrids and further evaluate them for bioactivities. The molecular descriptors AATS8i, AVP-1, MoRSEE17 and GATSe7 were found to be active in predicting the structure-activity relationship. Molecular docking and dynamics simulation studies of the developed leads have shown insights into structural analysis. Furthermore, computational studies using AutoDock and Desmond predicted the key binding interactions responsible for the activity and the SwissADME tool computed the in silico drug likeliness properties. The lead compound 178 generated through this study creates a route for the optimization and development of novel drugs against tuberculosis infections. RMSD, RMSF, RoG, H-bond and SASA analysis confirmed the stable binding of compound 178 with the 6J90 structure. In addition, MM-PBSA and MM-GBSA also confirm the docking results. We propose the designed compound 178 as the best theoretical lead, which may further be experimentally studied for selective inhibition.

Thiourea derivatives containing 4-arylthiazoles and d-glucose moiety: design, synthesis, antimicrobial activity evaluation, and molecular docking/dynamics simulations

Some substituted glucose-conjugated thioureas containing 1,3-thiazole ring, 4a-h, were synthesized by the reaction of the corresponding substituted 2-amino-4-phenyl-1,3-thiazoles 2a-h with 2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl isocyanate. The antibacterial and antifungal activities of these thiazole-containing thioureas were estimated using a minimum inhibitory concentration protocol. Among these compounds, 4c, 4g, and 4h were better inhibitors with MIC = 0.78-3.125 μg mL-1. These three compounds were also tested for their ability to inhibit S. aureus enzymes, including DNA gyrase, DNA topoisomerase IV (Topo IV), and dihydrofolate reductase, and compound 4h was found to be a strong inhibitor with IC50 = 1.25 ± 0.12, 67.28 ± 1.21, and 0.13 ± 0.05 μM, respectively. Induced-fit docking and MM-GBSA calculations were performed to observe the binding efficiencies and steric interactions of these compounds. The obtained results showed that compound 4h is compatible with the active site of S. aureus DNA gyrase 2XCS with four H-bond interactions with residues Ala1118, Met1121, and F:DC11 and also three interactions with F:DG10 (two interactions) and F:DC11 (one interaction). Molecular dynamics simulation in a water solvent system showed that ligand 4h had active interactions with enzyme 2XCS through residues Ala1083, Glu1088, Ala1118, Gly1117, and Met1121.

Design, Synthesis and Biological Evaluation of 7-Substituted-1,3-diaminopyrrol[3,2-f]quinazolines as Potential Antibacterial Agents

The evolution of drug-resistant bacteria poses a serious threat to public health; hence, it is imperative to develop new and efficient antibiotics. Irresistin-16 (IRS-16) is a dual-target antibacterial candidate that affects folate biosynthesis and membrane integrity and exhibits potent lethality against various bacteria. In this study, a series of 1,3-diamino-7H-pyrrol[3,2-f]quinazoline (DAPQ) derivatives based on IRS-16 was designed and synthesized to identify outstanding antibacterial candidates. The most promising compound, 7-(4-(4-methylpiperazin-1-yl) benzyl)-7H-pyrrol[3,2-f] quinazoline-1,3-diamine (18 e), displayed excellent antibacterial activity against both gram-positive and gram-negative bacteria (minimum inhibitory concentrations=1-4 μg/mL), improved water solubility, poor hemolytic activity and low cytotoxicity. Compound 18 e exhibited rapid bactericidal properties and prevented bacterial resistance in laboratory simulations. These results provide a basis for the development of new DAPQ-based compounds to combat emerging bacterial resistance.

In silico design of novel CDK2 inhibitors through QSAR, ADMET, molecular docking and molecular dynamics simulation studies

The present study aims to investigate about the quantitative structure-activity relationship (QSAR) of a series of Thiazole derivatives reported as anticancer agents (hepatocellular carcinoma), using principally the electronic descriptors calculated by the DFT method and by applying the multiple linear regression method. The developed model showed good statistical parameters (R2 = 0.725, R2adj = 0.653, MSE = 0.060, R2test = 0.827, Q2cv = 0.536). The energy EHOMO orbital, electronic energy (TE), shape coefficient (I), number of rotatable bonds (NROT), and index of refraction (n) were revealed to be the main descriptors influencing the anti-cancer activity. Further, new Thiazole derivatives have been designed and their activities and pharmacokinetic properties have been predicted using the validated QSAR model. The designed molecules were then assessed to molecular docking (MD), and molecular dynamic (MDs) simulation accompanied by the calculation of the binding affinity using MMPBSA script according to 100 ns a simulation trajectory, to study both their affinity and their stability towards CDK2 as a target protein for the cancer disease treatment. This research concluded with the identification of four new CDK2 inhibitors which are A1, A3, A5, and A6 showing good pharmacokinetic properties. The MDs results revealed that the newly designed compound A5 remained stable in the active center of the discovered CDK2 protein, indicating its potential as a novel inhibitor for the treatment of hepatocellular carcinoma. The current findings may eventually contribute to the development of robust CDK2 inhibitors in the future.Communicated by Ramaswamy H. Sarma.

Synthesis of 3-Thiocyanobenzothiophene via Difunctionalization of Active Alkyne Promoted by Electrochemical-Oxidation

A novel and green method for the synthesis of 3-thiocyanatobenzothiophenes via electrochemical-oxidation promoted difunctionalization of active alkyne has been developed. In this protocol, inexpensive and easily available potassium thiocyanate was chosen as the thiocyanation reagent, 2-alkynylthioanisoles as the substrates, a variety of 3-thiocyanatobenzothiophenes were obtained in moderate to good yields under oxidant- and catalyst-free conditions. Moreover, the continuous flow system has good applicability for this transformation, the use of continuous flow system has overcome the disadvantage of low efficiency in traditional electrochemical amplification, and realized the stable and excellent yields of target products in the scale-up reactions.

One-Pot Synthesis of 1-Thia-4-azaspiro[4.4/5]alkan-3-ones via Schiff Base: Design, Synthesis, and Apoptotic Antiproliferative Properties of Dual EGFR/BRAFV600E Inhibitors

In this investigation, novel 4-((quinolin-4-yl)amino)-thia-azaspiro[4.4/5]alkan-3-ones were synthesized via interactions between 4-(2-cyclodenehydrazinyl)quinolin-2(1H)-one and thioglycolic acid catalyzed by thioglycolic acid. We prepared a new family of spiro-thiazolidinone derivatives in a one-step reaction with excellent yields (67-79%). The various NMR, mass spectra, and elemental analyses verified the structures of all the newly obtained compounds. The antiproliferative effects of 6a-e, 7a, and 7b against four cancer cells were investigated. The most effective antiproliferative compounds were 6b, 6e, and 7b. Compounds 6b and 7b inhibited EGFR with IC₅₀ values of 84 and 78 nM, respectively. Additionally, 6b and 7b were the most effective inhibitors of BRAF^V600E (IC₅₀ = 108 and 96 nM, respectively) and cancer cell proliferation (GI₅₀ = 35 and 32 nM against four cancer cell lines, respectively). Finally, the apoptosis assay results revealed that compounds 6b and 7b had dual EGFR/BRAF^V600E inhibitory properties and showed promising antiproliferative and apoptotic activity.

Application and synthesis of thiazole ring in clinically approved drugs

The development of heterocyclic derivatives has progressed considerably over the past few decades, and many new agents of synthetic and natural origin have been produced. Among heterocyclic compounds, thiazole is a unique five-membered heterocyclic motif characterized by nitrogen and sulfur atoms, which is widely used as an important core skeleton in a variety of pharmaceutically important compounds due to their diverse biological activities, such as antibacterial, antivirus, and antifungal. To the best of our knowledge, more than 90 thiazole-containing derivatives have been currently under clinical investigation, and some thiazole analogs have been approved to treat various diseases. As the potentially privileged scaffolds, thiazole derivatives can be further extensively explored to search for new drugs characterized by improved therapeutic efficacy and similar biological targets. This review aims to outline the applications and synthetic routes of some representative thiazole-containing drugs approved in the clinic, which may guide medicinal researchers to rationally design more effective thiazole-containing drug candidates.

Abdellattif. Indenyl-thiazole and indenyl-formazan derivatives: Synthesis, anticancer screening studies, molecular-docking, and pharmacokinetic/ molin-spiration properties

Two new series of thiazole and formazan linked to 5-Bromo-indan were synthesized, and their structures were assured based on all possible analytical techniques. The size of the tested derivatives was calculated from the XRD technique and found five derivatives 3, 10a, 14a, 15, and 16 on the nanosized scale. The two series were tested for their efficacy and toxicity as anti-colon and stomach cancers. Derivative 10d showed activity more than the two reference drugs used in the case of SNU-16. Surpislly, in the case of COLO205, five derivatives 4, 6c, 6d, 6e, and 10a are better than the two benchmarks used, and two derivatives, 14a and 14b more potent than cisplatin. All potent derivatives showed a strong fit with the active site of the two tested proteins (gastric cancer (PDB = 2BID) and colon cancer (PDB = 2A4L)) in the molecular docking study. The Pharmacophore and ADME studies of the new derivatives showed that most derivatives revealed promising bioactivity, which indicates the drug-likeness properties against kinase inhibitors, protease, and enzyme inhibitors. In addition, the ProTox-II showed that the four compounds 10d, 16, 6d, and 10a are predicted to have oral LD50 values ranging from 335 to 3500 mg/kg in a rat model with (1 s,4 s)-Eucalyptol bearing the highest values and quercetin holding the lowest one.

Catalyst free one pot three components synthesis of 2-iminothiazoles from nitroepoxides and thiourea

Nitroepoxides were introduced as efficient substrates for the one-pot three-component synthesis of 2-iminothiazoles under catalyst-free conditions. Reaction of amines, isothiocyanates, and nitroepoxides in THF at 10-15 °C afforded corresponding 2-iminothiazoles in high to excellent yields. The reaction proceeds via the in situ formation of thiourea from an amine and an isothiocyanate, followed by nitroepoxide ring opening with the sulfur of thiourea, cyclization reaction, and dehydration cascade. The structures of products were confirmed by IR, NMR, HRMS analyses and X-ray crystallography.

Rhodium-catalyzed selenylation and sulfenylation of quinoxalinones 'on water'

A rhodium-catalysed, regioselective synthetic methodology for selenylation and sulfenylation of 3-phenyl quinoxolinones has been developed through N-directed C-H activation in the presence of silver triflimide, and silver carbonate using dichalcogenides 'on water'. The methodology has been proven to be efficient, regioselective and green. Using this method, a range of selenylations and sulfenylations of the substrates has been carried out in good to excellent yields. Further, late-stage functionalisation produced potential anti-tumour, anti-fungal and anti-bacterial agents making these compounds potential drug candidates.

Trends and hotspots for European Journal of Medicinal Chemistry: A bibliometric study

European Journal of Medicinal Chemistry (EJMC) has been around for a long time and has gained broad interest from the various individuals working in the field. However, there is no bibliometric analysis on the publications of EJMC to thoroughly assess the scientific output and current status systematically. Therefore, the study was conducted to analyze the various publications of EJMC from 1987 to 2022 to improve their quality. A total of 13,386 papers were retrieved, with the number of publications increasing yearly. Based on the multiple indicators of bibliometrics, the highest impact countries, institutions, authors and representative literature were identified, and visualization networks were constructed using VOSviewer. Keyword co-occurrence analysis reveals a gradual shift from phenotypic drug discovery to target-based drug discovery in the EJMC theme change. Moreover, further discussion of the keyword clustering results is provided to support researchers in defining the scope of their research topics and planning their research directions. At this stage, there is a greater focus on developing antitumor and oxidative stress-related drugs than on the earlier anti-infective activities. In future studies, the main research directions are tumor multidrug resistance, oxidative stress, and dual inhibitors.

Thiamyxins: Structure and Biosynthesis of Myxobacterial RNA-Virus Inhibitors

During our search for novel myxobacterial natural products, we discovered the thiamyxins: thiazole- and thiazoline-rich non-ribosomal peptide-polyketide hybrids with potent antiviral activity. We isolated four congeners of this unprecedented natural product family with the non-cyclized thiamyxin D fused to a glycerol unit at the C-terminus. Alongside their structure elucidation, we present a concise biosynthesis model based on biosynthetic gene cluster analysis and isotopically labelled precursor feeding. We report incorporation of a 2-(hydroxymethyl)-4-methylpent-3-enoic acid moiety by a GCN5-related N-acetyltransferase-like decarboxylase domain featuring polyketide synthase. The thiamyxins show potent inhibition of RNA viruses in cell culture models of corona, zika and dengue virus infection. Their potency up to a half maximal inhibitory concentration of 560 nM combined with milder cytotoxic effects on human cell lines indicate the potential for further development of the thiamyxins.

Synthesis and in vitro antibacterial, antifungal, anti-proliferative activities of novel adamantane-containing thiazole compounds

A series of (Z)-N-(adamantan-1-yl)-3,4-diarylthiazol-2(3H)-imines (5a-r) was synthesized via condensation of 1-(adamantan-1-yl)-3-arylthioureas (3a-c) with various aryl bromomethyl ketones (4a-f). The structures of the synthesized compounds were characterized by ¹H NMR, ¹³C NMR and by X-ray crystallography. The in vitro inhibitory activities of the synthesized compounds were assessed against a panel of Gram-positive and Gram-negative bacteria, and pathogenic fungi. Compounds 5c, 5g, 5l, 5m, and 5q displayed potent broad-spectrum antibacterial activity, while compounds 5a and 5o showed activity against the tested Gram-positive bacteria. Compounds 5b, 5l and 5q displayed potent antifungal activity against Candida albicans. In addition, the synthesized compounds were evaluated for anti-proliferative activity towards five human tumor cell lines. The optimal anti-proliferative activity was attained by compounds 5e and 5k which showed potent inhibitory activity against all the tested cell lines. Molecular docking analysis reveals that compounds 5e and 5k can occupy the positions of NAD cofactor and the histone deacetylase inhibitor EX527 at the active site of SIRT1 enzyme.

A new series of thiazole‐hydrazone hybrids for Akt‐targeted therapy of non‐small cell lung cancer

In an attempt to identify potent antitumor agents for the fight against non-small cell lung cancer, new thiazolyl hydrazones (2a-n) were synthesized and examined for their in vitro cytotoxic effects on A549 human lung adenocarcinoma and L929 mouse embryonic fibroblast cells by means of the MTT assay. Furthermore, the effects of the most potent anticancer agents on apoptosis and Akt inhibition were investigated. 2-[2-((Isoquinolin-5-yl)methylene)hydrazinyl]-4-(4-methylsulfonylphenyl)thiazole (2k) (IC₅₀  = 1.43 ± 0.12 µM) and 2-[2-((isoquinolin-5-yl)methylene)hydrazinyl]-4-(1,3-benzodioxol-5-yl)thiazole (2l) (IC₅₀  = 1.75 ± 0.07 µM) displayed more pronounced anticancer activity than cisplatin (IC₅₀  = 3.90 ± 0.10 µM) on A549 cell lines; 2-[2-((isoquinolin-5-yl)methylene)hydrazinyl]-4-(4-methoxyphenyl)thiazole (2j) (IC₅₀  = 3.93 ± 0.06 µM) showed anticancer activity close to cisplatin. These compounds were found to induce apoptosis in A549 cells. Compound 2j (IC₅₀  = 3.55 ± 0.64 µM) showed stronger Akt inhibitory activity than GSK690693 (IC₅₀  = 4.93 ± 0.06 µM), while compounds 2k and 2l did not cause Akt inhibition at IC₅₀ concentrations (1.43 and 1.75 µM, respectively). To comprehensively elucidate the binding pose of compound 2j and to provide a detailed understanding on the ligand' binding mechanism, induced-fit docking calculations were also conducted. Both in vitro and in silico studies suggest that compound 2j shows its cytotoxic and apoptotic effects on A549 cell lines via Akt inhibition. However, it is understood that compounds 2k and 2l exert their strong anticancer effects on A549 cells through different pathways.

Synthesis, Antibacterial, and Antioxidant Activities of Thiazolyl-Pyrazoline Schiff Base Hybrids: A Combined Experimental and Computational Study

Thiazole-pyrazoline Schiff base hybrids have a broad range of pharmacological potential with an ability to control the activity of numerous metabolic enzymes. In this work, a greener and more efficient approach has been developed to synthesize a novel series of thiazole-pyrazoline Schiff base hybrids using ZnO nanoparticle-assisted protocol in good to excellent yields (78.3–96.9%) and examined their antibacterial activity against Gram-positive and Gram-negative bacteria, as well as their antioxidant activity. Compound 24 (IZD = 18.67 ± 0.58) displayed better activity against P. aeruginosa compared with amoxicillin (IZD = 14.33 ± 2.52) at 250 μg/mL, whereas compounds 22 and 24 (IZD = 13.33 ± 0.58 mm and 17.00 ± 1.00 mm, respectively) showed better activity against E. coli compared with amoxicillin (IZD = 14.67 ± 0.58 mm) at 500 μg/mL. The remaining compounds showed moderate to weak activity against the tested bacterial strains. Compound 21 displayed significant inhibition of DPPH (IC50 = 4.63 μg/mL) compared with ascorbic acid (IC50 = 3.21 μg/mL). Compound 21 displayed 80.01 ± 0.07% inhibition of peroxide formation, suggesting its potential in preventing the formation of lipid peroxides. The results of the ADMET study showed that all synthesized compounds obeyed Lipinski's rule of five. In silico pharmacokinetic study demonstrated that compound 24 had superior intestinal absorption compared with amoxicillin. In silico molecular docking analysis revealed a binding affinity of −9.9 Kcal/mol for compound 24 against PqsA compared with amoxicillin (−7.3 Kcal/mol), whereas compounds 22 and 24 displayed higher binding affinity (−8.5 and −7.9 Kcal/mol, respectively) with DNA gyrase B compared with amoxicillin (-7.1 Kcal/mol), in good agreement with in vitro antibacterial activity against P. aeruginosa and E. coli. In silico toxicity study showed that all synthesized compounds had LD50 (mg/kg) values ranging from 800 to 1,000 putting them in ProTox-II class 4. The in vitro antibacterial activity and molecular docking analysis showed that compound 24 is a promising antibacterial therapeutic agent against P. aeruginosa and E. coli and compound 22 is a promising antibacterial agent against E. coli, whereas compound 21 is found to be a potential natural antioxidant agent. Moreover, the green synthesis approach using ZnO nanoparticle as catalyst was found to be a very efficient method to synthesize biologically active thiazole-pyrazoline Schiff base hybrids compared with the conventional method.