Thiazole Ring-A Biologically Active Scaffold

Fluorinated indeno-quinoxaline bearing thiazole moieties as hypoglycaemic agents targeting α-amylase, and α-glucosidase: synthesis, molecular docking, and ADMET studies

Inhibition of α-glucosidase and α-amylase are key tactics for managing blood glucose levels. Currently, stronger, and more accessible inhibitors are needed to treat diabetes. Indeno[1,2-b] quinoxalines-carrying thiazole hybrids 1-17 were created and described using NMR. All analogues were tested for hypoglycaemic effect against STZ-induced diabetes in mice. Compounds 4, 6, 8, and 16 were the most potent among the synthesised analogues. These hybrids were examined for their effects on plasma insulin, urea, creatinine, GSH, MDA, ALT, AST, and total cholesterol. Moreover, these compounds were tested against α-glucosidase and α-amylase enzymes in vitro. The four hybrids 4, 6, 8, and 16 represented moderate to potent activity with IC50 values 0.982 ± 0.04, to 10.19 ± 0.21 for α-glucosidase inhibition and 17.58 ± 0.74 to 121.6 ± 5.14 μM for α-amylase inhibition when compared to the standard medication acarbose with IC50=0.316 ± 0.02 μM for α-glucosidase inhibition and 31.56 ± 1.33 μM for α-amylase inhibition. Docking studies as well as in silico ADMT were done.

Design, selective synthesis and biological activities evaluation of novel thiazol-2-ylbenzamide and thiazole-2-ylbenzimidoyl chloride derivatives

To promote the development and exploitation of novel antifungal agents, a series of thiazol-2-ylbenzamide derivatives (3A-3V) and thiazole-2-ylbenzimidoyl chloride derivatives (4A-4V) were designed and selective synthesis. The bioassay results showed that most of the target compounds exhibited excellent in vitro antifungal activities against five plant pathogenic fungi (Valsa mali, Sclerotinia scleotiorum, Botrytis cinerea, Rhizoctonia solani and Trichoderma viride). The antifungal effects of compounds 3B (EC50 = 0.72 mg/L) and 4B (EC50 = 0.65 mg/L) against S. scleotiorum were comparable to succinate dehydrogenase inhibitors (SDHIs) thifluzamide (EC50 = 1.08 mg/L) and boscalid (EC50 = 0.78 mg/L). Especially, compounds 3B (EC50 = 0.87 mg/L) and 4B (EC50 = 1.08 mg/L) showed higher activity against R. solani than boscalid (EC50 = 2.25 mg/L). In vivo experiments in rice leaves revealed that compounds 3B (86.8 %) and 4B (85.3 %) exhibited excellent protective activities against R. solani comparable to thifluzamide (88.5 %). Scanning electron microscopy (SEM) results exhibited that compounds 3B and 4B dramatically disrupted the typical structure and morphology of R. solani mycelium. Molecular docking demonstrated that compounds 3B and 4B had significant interactions with succinate dehydrogenase (SDH). Meanwhile, SDH inhibition assay results further proved their potential as SDHIs. In addition, acute oral toxicity tests on A. mellifera L. showed only low toxicity for compounds 3B and 4B to A. mellifera L. populations. These results suggested that these two series of compounds had merit for further investigation as potential low-risk agricultural SDHI fungicides.

HFIP-Mediated Multicomponent Reactions: Synthesis of Pyrazole-Linked Thiazole Derivatives

The development of one-pot, atom, and step-economic new methods avoiding metal, harsh reaction conditions, and toxic reagents for the synthesis of medicinally important hybrid molecules bearing more than one bioactive moieties is currently one of the hot topics in organic synthesis. Herein, we report a green and efficient room temperature multicomponent reaction for the synthesis of novel pyrazole-linked thiazoles involving a one-pot C-C, C-N, and C-S bond-forming process from the reaction of aryl glyoxal, aryl thioamide, and pyrazolones in 1,1,1,3,3,3-hexafluoroisopropanol, a hydrogen bond donating reaction medium. A set of diverse hybrid molecules bearing thiazole and pyrazole moieties were prepared in good to excellent yields by using this method. This methodology can also be extended to prepare thiazole-linked barbiturates as well as imidazole-linked pyrazoles. All the products were fully characterized by spectroscopic techniques. The notable features of this protocol are room temperature, metal as well as additive-free reaction conditions, use of recyclable solvent, water as the byproduct, wide substrate scope, operational simplicity, easy purification, applicability for gram-scale synthesis, high atom economy, and the presence of two bioactive pyrazole and thiazole moieties in the products.

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.

New thiazole, thiophene and 2-pyridone compounds incorporating dimethylaniline moiety: synthesis, cytotoxicity, ADME and molecular docking studies

Various sets of thiazole, thiophene, and 2-pyridone ring structures containing a dimethylaniline component were synthesized. Substituted thiazoles 2-3 and thiophenes 5-7 were produced by reacting thiocarbamoyl compound 4 with α-halogenated reagents in different basic conditions. Also, a series of 2-pyridone derivatives 9a-f substituted with dimethylaniline was synthesized through Michael addition of malononitrile to α,β-unsaturated nitrile derivatives 8a-f. The synthesized products were structurally proven by spectroscopic methods such as IR, 1H NMR, 13C NMR, and MS data. Furthermore, the anti-cancer efficacy of the compounds was assessed using the MTT assay on two cell lines: hepatocellular carcinoma (HepG-2) and breast cancer (MDA-MB-231). The results showed the highest growth inhibition for derivatives 2, 6, 7, and 9c, which were further examined for their IC50 values. The IC50 for compound 2 showed equipotent activity (IC50 = 1.2 µM) against the HepG-2 cell line compared to Doxorubicin (IC50 = 1.1 µM). Compounds 2, 6, 7 and 9c showed very good ADME assessments for further drug administration. Moreover, the PASS theoretical prediction for the compounds showed high antimitotic and antineoplastic activities for compounds 2, 6, 7, and 9c, as well as potent inhibition activity for the insulysin enzyme (IDE). Molecular docking stimulations were performed on CDK1/CyclinB1/CKS2 (PDB ID: 4y72) and BPTI (PDB ID: 2ra3). When docked into (PDB ID: 4y72), all of the tested compounds showed considerable inhibition, and the 2-pyridone derivative 9d had the maximum binding affinity (- 8.1223 kcal/mol). While thiophene derivative 6 offered the maximum binding affinity (- 7.5094 kcal/mol) when docked into (PDB ID: 2ra3).

Synthesis of tetrazole hybridized with thiazole, thiophene or thiadiazole derivatives, molecular modelling and antimicrobial activity

Background

Tetrazole-based derivatives and their electronic structures have displayed interesting antimicrobial activity.

Methods

The tetrazole-based hybrids linked with thiazole, thiophene and thiadiazole ring systems have been synthesized through various chemical reactions. The computational method DFT/B3LYP has been utilized to calculate their electronic properties. The antimicrobial effectiveness was investigated against representative bacterial and fungal strains. Additionally, the synthesized derivatives binding interaction was stimulated by docking program against PDB ID: 4URO as a model of the ATP binding domain of S. aureus DNA Gyrase subunit B.

Results

The structures of the synthesized tetrazole-based derivatives were confirmed by IR, NMR, and Mass spectroscopic data. The DFT/B3LYP method showed that the thiadiazole derivatives 9a-c had lower ΔEH-L than the thiophenes 7a-c and thiazoles 5a-c. The hybrids 5b, 5c, and 7b exhibited proper antibacterial activity against Gram's +ve bacterial strains (S. aureus and S. pneumonia), while 9a displayed potent activity towards Gram's -ve bacterial strains (S. typhimurium and E. coli). Meanwhile, derivatives 5a-b, 7a, 7c, and 9c showed good effectiveness towards fungal strain (C. albicans).

Conclusion

The study provides valuable tetrazole core-linked heterocyclic rings and opens the door to further research on their electrical characteristics and applications. Tetrazoles and thiazoles have antibacterial properties in pharmacological frameworks, making these hybrids potential lead molecules for drug development. The conclusion summarizes the data and suggests that the synthesized chemicals' interaction with a particular protein domain suggests focused biological activity.

Thiazolotriazoles As Anti-infectives: Design, Synthesis, Biological Evaluation and In Silico Studies

The rational design of novel thiazolo[2,3-c][1,2,4]triazole derivatives was carried out based on previously identified antitubercular hit molecule H127 for discovering potent compounds showing antimicrobial activity. The designed compounds were screened for their binding efficacies against the antibacterial drug target enoyl-[acyl-carrier-protein] reductase, followed by prediction of drug-likeness and ADME properties. The designed analogues were chemically synthesized, characterized by spectroscopic techniques, followed by evaluation of antimicrobial activity against bacterial and fungal strains, as well as antitubercular activity against M. tuberculosis and M. bovis strains. Among the synthesized compounds, five compounds, 10, 11, 35, 37 and 38, revealed antimicrobial activity, albeit with differential potency against various microbial strains. Compounds 10 and 37 were the most active against S. mutans (MIC: 8 μg/mL), while compounds 11 and 37 showed the highest activity against B. subtillis (MIC: 16 μg/mL), whereas compounds 10, 11 and 37 displayed activities against E. coli (MIC: 16 μg/mL). Meanwhile, compounds 10 and 35 depicted activities against S. typhi (MIC: 16 μg/mL) and compound 10 showed antifungal activity against C. albicans (MIC: 32 μg/mL). The current study has identified two broad-spectrum antibacterial hit compounds (10 and 37). Further structural investigation on these molecules is underway to enhance their potency.

Iodine-Promoted Thioylation and Dicarbonylation of Enaminone α-C Sites: Synthesis of Fully Substituted Thiazoles via C═C Bond Cleavage

A novel iodine-promoted difunctionalization of α-C sites in enaminones was demonstrated as a means of synthesizing a variety of fully substituted thiazoles by constructing C-C(CO), C-S, and C-N bonds. This transformation allows the realization of enaminones as unusual aryl C2 synthons and simultaneously allows the thioylation and dicarbonylation of α-C sites. A preliminary mechanistic study was performed and indicated that the cleavage of C═C bonds in enaminones involves a bicyclization/ring-opening and oxidative coupling sequence.

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.

New thiazolyl-isoxazole derivatives as potential anti-infective agents: design, synthesis, in vitro and in silico antimicrobial efficacy

Antimicrobial resistance threatens the efficacious prevention and treatment of infectious diseases caused by microorganisms. To combat microbial infections, the need for new drug candidates is essential. In this context, the design, synthesis, antimicrobial screening, and in silico study of a new series of 5-aryl-3-(2-arylthiazol-4-yl)isoxazole (9a-t) have been reported. The structure of new compounds was confirmed by spectrometric methods. Compounds 9a-t were evaluated for in vitro antitubercular and antimicrobial activity. Against M. tuberculosis H37Rv, fourteen compounds showed good to excellent antitubercular activity with MIC 2.01-9.80 µM. Compounds 9a, 9b, and 9r showed four-fold more activity than the reference drug isoniazid. Nine compounds, 9a, 9b, 9d, 9e, 9i, 9q, 9r, 9s, and 9t, showed good antibacterial activity against E. coli with MIC 7.8-15.62 µg/mL. Against A. niger, four compounds showed good activity with MIC 31.25 µg/mL. Against C. albicans, all twenty compounds reported excellent to good activity with MIC 7.8-31.25 µg/mL. Compounds 9c-e, 9g-j, and 9q-t showed comparable activity concerning the reference drug fluconazole. The compounds 9a-t were screened for cytotoxicity against 3t3l1 cell lines and found to be less or non-cytotoxic. The in silico study exposed that these compounds displayed high affinity towards the M. tuberculosis targets PanK, DprE1, DHFR, PknA, KasA, and Pks13, and C. albicans targets NMT, CYP51, and CS. The compound 9r was evaluated for structural dynamics and molecular dynamics simulations. The potent antitubercular and antimicrobial activity of 5-aryl-3-(2-arylthiazol-4-yl)isoxazole (9a-t) derivatives has recommended that these compounds could assist in treating microbial infections.Communicated by Ramaswamy H. Sarma.

An Overview of the Structure-Activity Relationship in Novel Antimicrobial Thiazoles Clubbed with Various Heterocycles (2017-2023)

Antimicrobial resistance is an increasing problem for global public health. One of the strategies to combat this issue is the synthesis of novel antimicrobials through rational drug design based on extensive structure-activity relationship studies. The thiazole nucleus is a prominent feature in the structure of many authorized antimicrobials, being clubbed with different heterocycles. The purpose of this review is to study the structure-activity relationship in antimicrobial thiazoles clubbed with various heterocycles, as reported in the literature between 2017 and 2023, in order to offer an overview of the last years in terms of antimicrobial research and provide a helpful instrument for future research in the field.

Synthetic product-based approach toward potential antileishmanial drug development

Leishmaniasis is a parasitic disease and is categorized as a tropically neglected disease (NTD) with no effective vaccines available. The available chemotherapeutics against leishmaniasis are associated with an increase in the incidence of toxicity and drug resistance. Consequently, targeting metabolic pathways and enzymes of parasites which differs from the mammalian host can be exploited to treat and overcome the resistance. The classical methods of identifying the structural fragments and the moieties responsible for the biological activities from the standard compounds and their modification are options for developing more effective novel compounds. Significant progress has been made in refining the development of potent non-toxic molecules and addressing the limitations of the current treatment available. Several examples of synthetic product-based approach utilizing their core heterocyclic rings including furan, pyrrole, thiazole, imidazole, pyrazole, triazole, quinazoline, quinoline, pyrimidine, coumarin, indole, acridine, oxadiazole, purine, chalcone, carboline, phenanthrene and metal containing derivatives and their structure-activity relationships are discussed in this review. It also analyses the groups/fragments interacting with the host cell receptors and will support the medicinal chemists with novel antileishmanial agents.

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.

Parallel Synthesis of Piperazine Tethered Thiazole Compounds with Antiplasmodial Activity

Thiazole and piperazine are two important heterocyclic rings that play a prominent role in nature and have a broad range of applications in agricultural and medicinal chemistry. Herein, we report the parallel synthesis of a library of diverse piperazine-tethered thiazole compounds. The reaction of piperazine with newly generated 4-chloromethyl-2-amino thiazoles led to the desired piperazine thiazole compounds with high purities and good overall yields. Using a variety of commercially available carboxylic acids, the parallel synthesis of a variety of disubstituted 4-(piperazin-1-ylmethyl)thiazol-2-amine derivatives is described. the screening of the compounds led to the identification of antiplasmodial compounds that exhibited interesting antimalarial activity, primarily against the Plasmodium falciparum chloroquine-resistant Dd2 strain. The hit compound 2291-61 demonstrated an antiplasmodial EC50 of 102 nM in the chloroquine-resistant Dd2 strain and a selectivity of over 140.

In silico study, synthesis, and antineoplastic evaluation of thiazole-based sulfonamide derivatives and their silver complexes with expected carbonic anhydrase inhibitory activity

This study aimed to design, synthesize, and evaluate the cytotoxic activity of novel thiazole-sulfanilamide derivatives, specifically compounds M3, M4, and M5, through molecular docking and biological assays. The synthesis utilized essential chemical compounds, including sulfanilamide, chloro-acetyl chloride, thiourea, derivatives of benzaldehyde, and silver nitrate. The docking study was carried out using Molecular Operating Environment (MOE) software, and cytotoxic activity was predicted by MTT assay. The synthesized compounds demonstrated a reduction in the viability of cancer cells. Compound M5 had an IC50 of 18.53 µg/ml against MCF-7 cells, comparable to the IC50 of cisplatin. Additionally, compounds M3 and M4 had higher S scores than acetazolamide, indicating greater binding affinity to the active pocket of the receptor. Incorporating the thiazole ring in the synthesized compound augmented their flexibility and affinity for binding to the receptor. The inclusion of the metal complex additionally heightened the compounds' capacity to impede cellular growth.

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.

Novel Scaffolds Based on Bis-thiazole Connected to Quinoxaline or Thienothiophene through 2-Phenoxy-N-arylacetamide Groups as New Hybrid Molecules: Synthesis, Antibacterial Activity, and Molecular Docking Investigations

The resistance of microorganisms to antimicrobials has endangered the health of many people across the world. Overcoming the resistance problem will require the invention of molecules with a new mechanism of action so that no cross-resistance with existing therapies occurs. Because of their powerful antibacterial activity against a wide spectrum of Gram-positive and Gram-negative bacterial strains, heterocyclic compounds are appealing candidates for medicinal chemists. In this regard, as unique hybrid compounds, we synthesized a novel family of bis-thiazoles linked to quinoxaline or thienothiophene via the 2-phenoxy-N-arylacetamide moiety. The target compounds were synthesized by reacting the relevant bis(α-haloketones) with the corresponding thiosemicarbazones in EtOH at reflux with a few drops of TEA. Under comparable reaction conditions, the isomeric bis(thiazoles) were synthesized by reacting the appropriate bis(thiosemicarbazone) with the respective α-haloketones. The structures of the novel compounds were confirmed using elements and spectral data. All of the synthesized compounds were tested for antibacterial activity in vitro. With an inhibitory zone width of 12 mm, compound 12a had the same activity as the reference medication tobramycin against Staphylococcus aureus. Compound 12b showed 20 mg/mL as a minimum inhibitory concentration (MIC) against Bacillus subtilis. Some of the synthesized compounds were tested via molecular docking against two bacterial proteins (dihydrofolate reductase and tyrosyl-tRNA synthetase).

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.

Synthesis, anticancer activity and molecular modeling study of novel substituted triazole linked tetrafluoronaphthalene hybrid derivatives

To create some novel anticancer molecules, a library of novel series of various triazoles linked to the hydroxyl group of 5,6,7,8-tetrafluoronaphthalen-1-ol (3) was designed and synthesized via CuAAC reaction 'Click Chemistry' of tetrafluoronaphthalene based terminal alkyne with substituted organic azides. The structural characterizations of the targeted Click products 9-18 were confirmed by FTIR, 1H NMR, 19F NMR, 13C NMR and HRMS spectroscopy. Synthesized compounds were tested in two triple negative breast cancer (TNBC) cell lines to understand their anticancer potentials. According to our findings, compounds 14 and 13 showed high cytotoxicity in BT549 cells at 20 μM and 30 μM, respectively. Moreover, these compounds blocked the migration of BT549 cells. In the MDA-MB-231 cell line, compound 18 exhibited high cytotoxicity and can block cell migration for 24 h. Molecular docking study with synthesized novel compounds was performed by Glide/SP method against SphK1 drug target. Furthermore, molecular dynamics (MD) simulation was carried out for the compounds 12-14 and 18. The compounds 13 and 14 may be potential inhibitor candidates in place of a reference inhibitor. A pharmacophore model was generated with the most potent compound 14, and the approved drugs were screened using the modules of Discovery Studio to find similar drugs. Consequently, this comprehensive study encompassing design, synthesis, in vitro and in silico analyses were correlated with the structure-activity relationship between compounds. The findings have the potential to unveil promising drug candidates for future studies.Communicated by Ramaswamy H. Sarma.

Design, synthesis, anticancer activity and docking studies of novel quinazoline-based thiazole derivatives as EGFR kinase inhibitors

The in vitro anticancer efficacy of a new series of quinazoline-based thiazole derivatives was explored. Three cancer cell lines, MCF-7, HepG2, and A548, as well as the normal Vero cell lines, were tested employing the synthesized quinazoline-based thiazole compounds (4a-j). All of these compounds showed a moderate to significant cytotoxic impact that would have been noticeable and, in some cases, much more pronounced than the widely used drug erlotinib. For the MCF-7, HepG2, and A549 cell lines, respectively, the IC50 values of compound 4i were 2.86, 5.91, and 14.79 μM while those of compound 4j were 3.09, 6.87, and 17.92 μM. For their in vitro inhibitory effects against different EGFR kinases, such as the wild-type, L858R/T790 M, and L858R/T790 M/C797S, all the synthesized compounds were tested. The IC50 values for compound 4f against the wild-type, L858R/T790 M, and L858R/T790 M/C797S mutant EGFR kinases were 2.17, 2.81, and 3.62 nM, respectively. Investigations on the molecular docking of significant molecules indicated potential mechanisms of binding into the EGFR kinase active sites. By using in-silico simulations, compounds' putative drug-like qualities were verified. Finally, it has been shown that the newly synthesized compounds 4i and 4j are good candidates and beneficial for future design, optimization, and research to build more potent and selective EGFR kinase inhibitors with higher anticancer activity.

Rediscovering Cyanogen Gas for Organic Synthesis: Formation of 2-Cyanothiazole Derivatives

The expeditious synthesis of an API building block, 2-cyanothiazole, from cyanogen gas and a readily available dithiane is reported. A previously undisclosed partially saturated intermediate is formed, which can be further functionalized and isolated by the acylation of the hydroxy group. Dehydration using trimethylsilyl chloride furnished 2-cyanothiazole, which could be further converted to the corresponding amidine. The sequence provided a 55% yield over 4 steps. We envision that this work will spark further interest in cyanogen gas as a reactive and cost-effective synthetic reagent.

Favorable Heteroaromatic Thiazole-Based Polyurea Derivatives as Interesting Biologically Active Products

This research sought to synthesize a new set of heteroaromatic thiazole-based polyurea derivatives with sulfur links in the polymers' main chains, which were denoted by the acronyms PU_1-5. Using pyridine as a solvent, a diphenylsulfide-based aminothiazole monomer (M2) was polymerized via solution polycondensation with varied aromatic, aliphatic, and cyclic diisocyanates. Typical characterization methods were used to confirm the structures of the premonomer, monomer, and fully generated polymers. The XRD results revealed that aromatic-based polymers had higher crystallinity than aliphatic and cyclic derivatives. SEM was used to visualize the surfaces of PU₁, PU₄, and PU₅, revealing spongy and porous shapes, shapes resembling wooden planks and sticks, and shapes resembling coral reefs with floral shapes at various magnifications. The polymers demonstrated thermal stability. The numerical results for PDTmax are listed in the following order, ranked from lowest to highest: PU₁ < PU₂ < PU₃ < PU₅ < PU₄. The FDT values for the aliphatic-based derivatives (PU₄ and PU₅) were lower than those for the aromatic-based ones (616, 655, and 665 °C). PU₃ showed the greatest inhibitory impact against the bacteria and fungi under investigation. In addition, PU₄ and PU₅ demonstrated antifungal activities that, in contrast with the other products, were on the lower end of the spectrum. Furthermore, the intended polymers were also tested for the presence of the proteins 1KNZ, 1JIJ, and 1IYL, which are frequently utilized as model organisms for E. coli (Gram-negative bacteria), S. aureus (Gram-positive bacteria), and C. albicans (fungal pathogens). This study's findings are consistent with the outcomes of the subjective screening.

Synthesis of novel mono- and bis-pyrazolylthiazole derivatives as anti-liver cancer agents through EGFR/HER2 target inhibition

3-Bromoacetyl-4-(2-naphthoyl)-1-phenyl-1H-pyrazole (6) was synthesized from 2-acetylnaphthalene and was used as a new key building block for constructing the title targets. Thus, the reaction of 6 with the thiosemicarbazones 7a-d and 9-11 afforded the corresponding simple naphthoyl-(3-pyrazolyl)thiazole hybrids 8a-d and 12 ~ 14. The symmetric bis-(2-naphthoyl-pyrazol-3-yl)thiazol-2-yl)hydrazono)methyl)phenoxy)alkanes 18a-c and 21a-c were similarly synthesized from reaction of 6 with the appropriate bis-thiosemicarbazones 17a-c and 19a-c, respectively. The synthesized two series of simple and symmetrical bis-molecular hybrid merging naphthalene, thiazole, and pyrazole were evaluated for their cytotoxicity. Compounds 18b,c and 21a showed the most potent cytotoxicity (IC₅₀ = 0.97-3.57 µM) compared to Lapatinib (IC₅₀ = 7.45 µM). Additionally, they were safe (non-cytotoxic) against the THLE2 cells with higher IC₅₀ values. Compounds 18c exhibited promising EGFR and HER-2 inhibitory activities with IC₅₀ = 4.98 and 9.85 nM, respectively, compared to Lapatinib (IC₅₀ = 6.1 and 17.2 nM). Apoptosis investigation revealed that 18c significantly activated apoptotic cell death in HepG2 cells, increasing the death rate by 63.6-fold and arresting cell proliferation at the S-phase. Compound 18c upregulated P53 by 8.6-fold, Bax by 8.9-fold, caspase-3,8,9 by 9, 2.3, and 7.6-fold, while it inhibited the Bcl-2 expression by 0.34-fold. Thereby, compound 18c exhibited promising cytotoxicity against EGFR/HER2 inhibition against liver cancer.

Thiazole derivatives as dual inhibitors of deoxyribonuclease I and 5-lipoxygenase: A promising scaffold for the development of neuroprotective drugs

A library of 43 thiazole derivatives, including 31 previously and 12 newly synthesized in the present study, was evaluated in vitro for their inhibitory properties against bovine pancreatic DNase I. Nine compounds (including three newly synthesized) inhibited the enzyme showing improved inhibitory properties compared to that of the reference crystal violet (IC₅₀ = 346.39 μM). Two compounds (5 and 29) stood out as the most potent DNase I inhibitors, with IC₅₀ values below 100 μM. The 5-LO inhibitory properties of the investigated derivatives were also analyzed due to the importance of this enzyme in the development of neurodegenerative diseases. Compounds (12 and 29) proved to be the most prominent new 5-LO inhibitors, with IC₅₀ values of 60 nM and 56 nM, respectively, in cell-free assay. Four compounds, including one previously (41) and three newly (12, 29 and 30) synthesized, have the ability to inhibit DNase I with IC₅₀ values below 200 μM and 5-LO with IC₅₀ values below 150 nM in cell-free assay. Molecular docking and molecular dynamics simulations were used to clarify DNase I and 5-LO inhibitory properties of the most potent representatives at the molecular level. The newly synthesized compound 29 (4-((4-(3-bromo-4-morpholinophenyl)thiazol-2-yl)amino)phenol) represents the most promising dual DNase I and 5-LO inhibitor, as it inhibited 5-LO in the nanomolar and DNase I in the double-digit micromolar concentration ranges. The results obtained in the present study, together with our recently published results for 4-(4-chlorophenyl)thiazol-2-amines, represent a good basis for the development of new neuroprotective therapeutics based on dual inhibition of DNase I and 5-LO.

Development of thiazole-appended novel hydrazones as a new class of α-amylase inhibitors with anticancer assets: an in silico and in vitro approach

Hyperamylasemia is reported to be associated with numerous chronic diseases, including diabetes and cancer. Considering this fact, we developed a series of thiazole-clubbed hydrazones. The derivatives were explored for their in vitro α-amylase inhibitory activity, which was further corroborated with their anticancer assets using a panel of cancer cells, including colon cancer (HCT-116), lung cancer (A549), and breast cancer (MDA-MB-231). To better understand pharmacokinetics, the synthetic derivatives were subjected to in silico ADMET prediction. The in vitro based biological investigation revealed that compared to the reference drug acarbose (IC50 = 0.21 ± 0.008 μM), all the synthesized compounds (5a-5aa) exhibited in vitro α-amylase inhibitory response in the range of IC50 values from 0.23 ± 0.003 to 0.5 ± 0.0 μM. Along with this, the proliferations of the HCT-116, A549 and MDA-MB-231 cells were inhibited when treated with the synthesized compounds. Notable cancer cell growth inhibition was observed for compounds 5e, 5f and 5y, which correlated with their α-amylase inhibition. Additionally, the kinetics investigation revealed that 5b, 5e, 5f and 5y exhibit uncompetitive inhibition. 5b was found to be the least cytotoxic and most potent α-amylase inhibitor and was further validated by absorption and fluorescence quenching technique.

Recent Advances in the Synthesis of 3,4-Dihydropyran-2-Ones Organocatalyzed by N-Heterocyclic Carbenes

In recent years, N-heterocyclic carbenes (NHC) have gained recognition as versatile molecules capable of acting as organocatalysts in various reactions, particularly through the activation of aldehydes via Breslow-type adducts. This organocatalytic activation has enabled the production of numerous 3,4-dihydropyran-2-ones and related derivatives. In this review, we provide an overview of the production of 3,4-dihydropyran-2-ones and derivatives via organocatalytic processes involving NHCs over the past eight years. These processes involve the use of a diverse range of substrates, catalysts, and reaction conditions, which can be classified into [4+2]-and [3+3]-type cycloadditions, primarily aimed at synthesizing this skeleton due to its biological activity and multiple stereocenters. These processes are scaled up to the gram scale, and the resulting products are often directed towards epimerization and functionalization to produce more complex molecules with potential applications in the biological field. Finally, we provide a perspective and the future directions of this topic in organic synthesis.

New N-acyl Thiourea Derivatives: Synthesis, Standardized Quantification Method and In Vitro Evaluation of Potential Biological Activities

New N-acyl thiourea derivatives with heterocyclic rings have been synthesized by first obtaining isothiocyanate, which further reacted with a heterocyclic amine, characterized by (FT-IR, NMR spectroscopy and FT-ICR) and tested for their in vitro antimicrobial, anti-biofilm and antioxidant activities to obtain a drug candidate in a lead-optimization process. From the tested compounds, those bearing benzothiazole (1b) and 6-methylpyridine (1d) moieties revealed anti-biofilm activity against E. coli ATCC 25922 at MBIC values of 625 µg/mL. Compound 1d exhibited the highest antioxidant capacity (~43%) in the in vitro assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Considering the in vitro results, the highest anti-biofilm and antioxidant activities were obtained for compound 1d. Therefore, a reversed-phase high-performance liquid chromatography (RP-HPLC) method has been optimized and validated for the quantitative determination of compound 1d. The detection and quantitation limits were 0.0174 μg/mL and 0.0521 μg/mL, respectively. The R² correlation coefficient of the LOQ and linearity curves were greater than 0.99, over the concentration range of 0.05 μg/mL-40 μg/mL. The precision and accuracy of the analytical method were within 98-102%, confirming that the method is suitable for the quantitative determination of compound 1d in routine quality control analyses. Evaluating the results, the promising potential of the new N-acyl thiourea derivatives bearing 6-methylpyridine moiety will be further investigated for developing agents with anti-biofilm and antioxidant activities.

Computer-aided design of a cyclic di-AMP synthesizing enzyme CdaA inhibitor

Cyclic di-AMP (c-di-AMP) is an essential secondary messenger regulating cell wall homeostasis and myriads of physiological processes in several Gram-positive and mycobacteria, including human pathogens. Hence, c-di-AMP synthesizing enzymes (DACs) have become a promising antibacterial drug target. To overcome a scarcity of small molecule inhibitors of c-di-AMP synthesizing enzyme CdaA, a computer-aided design of a new compound that should block the enzyme has been performed. This has led to the identification of a molecule comprising two thiazole rings and showing inhibitory potential based on ITC measurements. Thiazole scaffold is a good pharmacophore nucleus known due to its various pharmaceutical applications. It is contained in more than 18 FDA-approved drugs as well as in dozens of experimental drugs. Hence, the designed inhibitor can serve as a potent lead compound for further development of inhibitor against CdaA.

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.

Novel Synthetic Derivative of Renieramycin T Right-Half Analog Induces Apoptosis and Inhibits Cancer Stem Cells via Targeting the Akt Signal in Lung Cancer Cells

Akt is a key regulatory protein of cancer stem cells (CSCs) and is responsible for cancer aggressiveness and metastasis. Targeting Akt is beneficial for the development of cancer drugs. renieramycin T (RT) has been reported to have Mcl-1 targeting activity, and the study of the structure-activity relationships (SARs) demonstrated that cyanide and the benzene ring are essential for its effects. In this study, novel derivatives of the RT right-half analog with cyanide and the modified ring were synthesized to further investigate the SARs for improving the anticancer effects of RT analogs and evaluate CSC-suppressing activity through Akt inhibition. Among the five derivatives, a compound with a substituted thiazole structure (DH_25) exerts the most potent anticancer activity in lung cancer cells. It has the ability to induce apoptosis, which is accompanied by an increase in PARP cleavage, a decrease in Bcl-2, and a diminishment of Mcl-1, suggesting that residual Mcl-1 inhibitory effects exist even after modifying the benzene ring to thiazole. Furthermore, DH_25 is found to induce CSC death, as well as a decrease in CSC marker CD133, CSC transcription factor Nanog, and CSC-related oncoprotein c-Myc. Notably, an upstream member of these proteins, Akt and p-Akt, are also downregulated, indicating that Akt can be a potential target of action. Computational molecular docking showing a high-affinity interaction between DH_25 and an Akt at the allosteric binding site supports that DH_25 can bind and inhibit Akt. This study has revealed a novel SAR and CSC inhibitory effect of DH_25 via Akt inhibition, which may encourage further development of RT compounds for cancer therapy.

Synthesis of 4-(4-chlorophenyl)thiazole compounds: in silico and in vitro evaluations as leishmanicidal and trypanocidal agents

Neglected tropical diseases are a diverse group of communicable pathologies that mainly prevail in tropical and subtropical regions. Thus, the objective of this work was to evaluate the biological potential of eight 4-(4-chlorophenyl)thiazole compounds. Tests were carried out in silico to evaluate the pharmacokinetic properties, the antioxidant, cytotoxic activities in animal cells and antiparasitic activities were evaluated against the different forms of Leishmania amazonensis and Trypanosoma cruzi in vitro. The in silico study showed that the evaluated compounds showed good oral availability. In a preliminary in vitro study, the compounds showed moderate to low antioxidant activity. Cytotoxicity assays show that the compounds showed moderate to low toxicity. In relation to leishmanicidal activity, the compounds presented IC50 values that ranged from 19.86 to 200 µM for the promastigote form, while for the amastigote forms, IC50 ranged from 101 to more than 200 µM. The compounds showed better results against the forms of T. cruzi with IC50 ranging from 1.67 to 100 µM for the trypomastigote form and 1.96 to values greater than 200 µM for the amastigote form. This study showed that thiazole compounds can be used as future antiparasitic agents.

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.

Novel 1,2,3-Triazole-Based Benzothiazole Derivatives: Efficient Synthesis, DFT, Molecular Docking, and ADMET Studies

A new series of 1,2,3-triazole derivatives 5a-f based on benzothiazole were synthesized by the 1,3-dipolar cycloaddition reaction of S-propargyl mercaptobenzothiazole and α-halo ester/amide in moderate to good yields (47-75%). The structure of all products was characterized by ¹H NMR, ¹³C NMR, and CHN elemental data. This protocol is easy and green and proceeds under mild and green reaction conditions with available starting materials. The structural and electronic analysis and ¹H and ¹³C chemical shifts of the characterized structure of 5e were also calculated by applying the B3LYP/6-31 + G(d, p) level of density functional theory (DFT) method. In the final section, all the synthesized compounds were evaluated for their anti-inflammatory activity by biochemical COX-2 inhibition, antifungal inhibition with CYP51, anti-tuberculosis target protein ENR, DPRE1, pks13, and Thymidylate kinase by molecular docking studies. The ADMET analysis of the molecules 5a-f revealed that 5d and 5a are the most-promising drug-like molecules out of the six synthesized molecules.

Synthesis, biological evaluation and molecular docking of new triphenylamine-linked pyridine, thiazole and pyrazole analogues as anticancer agents

A new series of pyridine, thiazole, and pyrazole analogues were synthesized. The pyridone analogues 4a-e were synthesized by treating N-aryl-2-cyano-3-(4-(diphenylamino)phenyl)acrylamides 3a-e with malononitrile. Many 4-arylidene-thiazolidin-5-one analogues 6a-d were obtained by Knoevenagel reactions of 4-(diphenylamino)benzaldehyde (1) with their corresponding thiazolidin-5-one derivatives 5a-d. The structural elucidation of the products was proven by the collections of spectroscopic methods such as IR, 1H NMR, 13C NMR, and MS data. Their anti-cancer activity was examined against two cell lines, MDA-MB-231 (mammary carcinomas) and A-549 (lung cancer). Compared with cisplatin as a reference standard drug, 6-amino-4-(4-(diphenylamino)phenyl)-2-oxo-1-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (4b) and 6-amino-4-(4-(diphenylamino)phenyl)-1-(4-nitrophenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile (4e) exhibited better efficiency against the A-549 cell line, with IC50 = 0.00803 and 0.0095 μM, respectively. Also, these compounds 4b and 4e showed the most potency among the examined compounds against MDA-MB-231 with IC50 = 0.0103 and 0.0147 μM, respectively. The newly synthesized compounds were docked inside the active sites of the selected proteins and were found to demonstrate proper binding. 2-Cyano-2-(4,4-(diphenylamino)benzylidene)-5-oxo-3-phenylthiazolidin-2-ylidene)-N-(p-tolyl)acetamide (6c) offered the highest binding affinity (− 8.1868 kcal/mol) when docked into (PDB ID:2ITO), in addition to 2-cyano-N-(4-(diethylamino)phenyl)-2-(4-(4-(diphenylamino)benzylidene)-5-oxo-3-phenylthiazolidin-2-ylidene)acetamide (6a) gave the highest energy score (− 9.3507 kcal/mol) with (PDB ID:2A4L).

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.

Multicomponent Synthesis of Fluorescent Thiazole-Indole Hybrids and Thiazole-Based Novel Polymers

Herein, we report an efficient multicomponent reaction for the synthesis of trisubstituted thiazoles involving a one-pot C-C, C-N, and C-S bond-forming process from the readily available starting materials. The reaction of arylglyoxal, indole, and aryl thioamides in the acetic acid medium under sealed heating conditions provided 3-(2,4-diarylthiazol-5-yl)-1H-indoles (4) in good to excellent yields. Using a similar reaction strategy, the reaction of arylglyoxal, aryl thioamide, and 2,5-dihydroxy-1,4-benzoquinone provided structurally interesting bis-thiazoles having dihydroxy-1,4-benzoquinone linker (9). All of the products were fully characterized by spectroscopic techniques. We also recorded single-crystal X-ray diffraction (XRD) of compounds 4b and 9a for unambiguous structure determination. Indole-linked trisubstituted thiazoles (4) exhibit prominent fluorescence properties. The relative fluorescence quantum yields of all of the thiazole-linked indoles were measured in the dimethyl sulfoxide (DMSO) medium with respect to quinine sulfate in 0.1 M H₂SO₄ as reference. The scope of this reaction was further explored by preparing novel polymers 11a and 11b using naphthalene/benzene-1,4-bis(carbothioamide) in multicomponent polymerization.

A green synthesis and antibacterial activity of ferrocene-based thiazole derivatives in choline chloride/glycerol eutectic solvent

In this work, a green Hantzsch synthesis of 4-ferrocenylthiazole derivatives has been accomplished successfully. The Hantzsch reaction between bromoacetylferrocene and various aryl thioureas, 1-alkylindole-3- or 9-alkylcarbazole-3-carbothioamides proceeded efficiently in a deep eutectic solvent (DES) that is, choline chloride/glycerol (ChCl/Gly) (1 : 2 molar ratio) at 80 °C, avoiding the use of common volatile organic solvents. Moreover, the DES media could be reused up to three times without any appreciable decrease in the yield. The synthetic strategy has the attractive features such as mild and environmentally benign reaction conditions, experimental simplicity, easy work-up procedure and good yields. Subsequently, a preliminary screening for in vitro antibacterial activities of all these newly-synthesized compounds revealed that the halo-substituted (F, Cl, Br) compounds 3f–h showed significant antibacterial activities against Gram (+) bacterial B. subtilis and Gram (−) E. coli, among which the fluoro-substituted 3f possessed the best activity with the MIC value of 7.8125 μg mL⁻¹, being higher than the reference drug ciprofoxacin (15.625 μg mL⁻¹).

A green and effective Hantzsch thiazole synthesis of structurally intriguing ferrocene-based derivatives employing the eutectic mixture choline chloride/glycerol (1 : 2 molar ratio) as a sustainable solvent is described.

Novel 1,3-Thiazole Analogues with Potent Activity against Breast Cancer: A Design, Synthesis, In Vitro, and In Silico Study

Breast cancer is the most common cancer in women, responsible for over half a million deaths in 2020. Almost 75% of FDA-approved drugs are mainly nitrogen- and sulfur-containing heterocyclic compounds, implying the importance of such compounds in drug discovery. Among heterocycles, thiazole-based heterocyclic compounds have demonstrated a broad range of pharmacological activities. In the present study, a novel set of 1,3-thiazole derivatives was designed and synthesized based on the coupling of acetophenone derivatives, and phenacyl bromide was substituted as a key reaction step. The activity of synthesized compounds was screened against the proliferation of two breast cancer cell lines (MCF-7 and MDA-MB-231). Almost all compounds exhibited a considerable antiproliferative activity toward the breast cancer cells as compared to staurosporine, with no significant cytotoxicity toward the epithelial cells. Among the synthesized compounds, compound 4 exhibited the most potent antiproliferative activity, with an IC₅₀ of 5.73 and 12.15 µM toward MCF-7 and MDA-MB-231 cells, respectively, compared to staurosporine (IC₅₀ = 6.77 and 7.03 µM, respectively). Exploring the mechanistic insights responsible for the antiproliferative activity of compound 4 revealed that compound 4 possesses a significant inhibitory activity toward the vascular endothelial growth factor receptor-2 (VEGFR-2) with (IC₅₀ = 0.093 µM) compared to Sorafenib (IC₅₀ = 0.059 µM). Further, compound 4 showed the ability to induce programmed cell death by triggering apoptosis and necrosis in MCF-7 cells and to induce cell cycle arrest on MCF-7 cells at the G1 stage while decreasing the cellular population in the G2/M phase. Finally, detailed in silico molecular docking studies affirmed that this class of compounds possesses a considerable binding affinity toward VEGFR2 proteins. Overall, these results indicate that compound 4 could be a promising lead compound for developing potent anti-breast cancer compounds.

Thiazole: A Versatile Standalone Moiety Contributing to the Development of Various Drugs and Biologically Active Agents

For many decades, the thiazole moiety has been an important heterocycle in the world of chemistry. The thiazole ring consists of sulfur and nitrogen in such a fashion that the pi (π) electrons are free to move from one bond to other bonds rendering aromatic ring properties. On account of its aromaticity, the ring has many reactive positions where donor–acceptor, nucleophilic, oxidation reactions, etc., may take place. Molecules containing a thiazole ring, when entering physiological systems, behave unpredictably and reset the system differently. These molecules may activate/stop the biochemical pathways and enzymes or stimulate/block the receptors in the biological systems. Therefore, medicinal chemists have been focusing their efforts on thiazole-bearing compounds in order to develop novel therapeutic agents for a variety of pathological conditions. This review attempts to inform the readers on three major classes of thiazole-bearing molecules: Thiazoles as treatment drugs, thiazoles in clinical trials, and thiazoles in preclinical and developmental stages. A compilation of preclinical and developmental thiazole-bearing molecules is presented, focusing on their brief synthetic description and preclinical studies relating to structure-based activity analysis. The authors expect that the current review may succeed in drawing the attention of medicinal chemists to finding new leads, which may later be translated into new drugs.

Structure, Spectra and Photochemistry of 2-Amino-4-Methylthiazole: FTIR Matrix Isolation and Theoretical Studies

The structure, tautomerization pathways, vibrational spectra, and photochemistry of 2-amino-4-methylthiazole (AMT) molecule were studied by matrix isolation FTIR spectroscopy and DFT calculations undertaken at the B3LYP/6-311++G(3df,3pd) level of theory. The most stable tautomer with the five-membered ring stabilized by two double C=C and C=N bonds, was detected in argon matrices after deposition. When the AMT/Ar matrices were exposed to 265 nm selective irradiation, three main photoproducts, N-(1-sulfanylprop-1-en-2-yl)carbodiimide (fp1), N-(1-thioxopropan-2-yl)carbodiimide (fp2) and N-(2-methylthiiran-2-yl)carbodiimide (fp3), were photoproduced by a cleavage of the CS–CN bond together with hydrogen atom migration. The minor photoreaction caused by the cleavage of the CS–CC bond and followed by hydrogen migration formed 2-methyl-1H-azirene-1-carbimidothioic acid (fp15). We have also found that cleavage of the CS–CN bond followed by disruption of the N–C bond produced cyanamide (fp11) and the C(CH3)=CH–S biradical that transformed into 2-methylthiirene (fp12) and further photoreactions produced 1-propyne-1-thiole (fp13) or methylthioketene (fp14). Cleavage of the CS–CC bond followed by disruption of the N–C bond produced propyne (fp22) and the S–C(NH₂)=N biradical that transformed into 3-aminethiazirene (fp23); further photoreactions produced N-sulfanylcarbodiimide (fp25). As a result of these transformations, several molecular complexes were identified as photoproducts besides new molecules in the AMT photolysis process.