Synthesis and evaluation of bis-thiazole derivatives as new anticancer agents

Synthesis of New Thiazole-Pyrazole Analogues: Molecular Modelling, Antiproliferative/Antiviral Activities, and ADME Studies

Twelve thiazole-pyrazole analogues 4, 6, and 8 were synthesized by introducing various pyrazole systems into the core, 2-((4-acetylphenyl)amino)-4-methylthiazole (2), through many synthetic approaches. The density functional theory (DFT) study of the synthesized analogues revealed coincided configurations of their highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO), except for the nitro derivatives, in which the intramolecular charge-transfer (CT) may be denoted as π → π* and n → π*. In addition, the in vitro antiproliferative efficacy towards some cancer cell lines was examined (Panc-1, HT-29, MCF-7) and the non-cancerous (WI-38), using Dasatinib (Reference). The analogues 4c and 4d demonstrated the most potent anticancer effect, particularly against Panc-1 and MCF-7 cells. Moreover, the antiviral activity against H5N1, using a plaque reduction assay, showed that analogue 6a exhibited the most potent antiviral activity (100% inhibition and TC50 = 61 μg/μL), comparable to the reference drug amantadine (TC50 = 72 μg/μL, 100% inhibition). Furthermore, the molecular docking disclosed that the analogues exhibited a range of interactions, such as H-bonding and π-π stacking, with binding affinities between -4.8558 and - 8.3673 kcal/mol. Additionally, the SwissADME predictions indicated that the synthesized analogues possess promising drug-like characteristics, but analogues 4a-d and 8c demonstrated inadequate solubility and bioavailability, which restricts their use as viable oral medications.

Reaction of unsymmetrical α-bromo-1,3-diketones with N-substituted thioureas: regioselective access to 2-(N-arylamino)-5-acyl-4-methylthiazoles and/or rearranged 2-(N-acylimino)-3-N-aryl-4-methylthiazoles

The present study reports some fascinating results of Hantzsch's [3 + 2] cyclic condensation of α-bromo-1,3-diketones, a tri-electrophilic synthon generated in situ by bromination of 1,3-diketones using the mild brominating reagent NBS with trinucleophilic N-substituted thioureas. Interestingly, out of a total of 20 combinations, 10 resulted in the exclusive formation of the desired 2-(N-arylamino)-5-acyl-4-methylthiazoles regioselectively, seven led to the formation of unexpected 2-(N-acylimino)-3-N-aryl-4-methylthiazoles through an interesting C-N acyl migration, and three furnished a mixture consisting of both products. The regioselectivity pattern of the two products may be attributed to a greater electrophilicity of the carbonyl carbon of the acetyl group than that of the acyl group towards both nitrogens of thiourea. The structures of the thiazole derivatives were unambiguously assigned using 1H-NMR, 13C-NMR, and rigorous heteronuclear 2D-NMR [(1H-13C) HMQC and (1H-13C) HMBC] spectroscopic techniques. The outcomes of the spectroscopic experiments were further concurred through X-ray crystallographic studies, and a plausible mechanism for acyl migration was proposed for the formation of the unexpected rearranged product.

Development of potential cathepsin B inhibitors: Synthesis of new bithiazole derivatives, in vitro studies supported with theoretical docking studies

Cysteine cathepsins play a crucial role in cancer, inflammation, and the regulation of degenerative processes such as apoptosis, making them significant targets in drug development. In this study, we designed, synthesized, and characterized sixteen novel bi-thiazole derivatives, confirmed by 1H NMR, 13C NMR, HRMS, and X-ray analysis, which demonstrated significant therapeutic potential as inhibitors of cathepsin B. The synthesized thiazoles showed % inhibition in the range of 59.11-77.32, out of which bis-methoxyphenyl derivative 8k showed the highest inhibition of 77.32 % with IC50 and ki values of 1.04 nM and 0.52 nM, respectively. Methoxy-containing derivatives 8c, 8g, 8i, 8j, 8l, and 8o showed improved inhibition over methyl and chloro. In silico studies of the new bis-thiazole compounds at cathepsin B active sites supported the in vitro findings, indicating that the synthesized bis-thiazole esters are promising therapeutic candidates for conditions involving elevated cathepsin B levels.

Thiazolobenzamide-Naphthalene Hybrids as Potent Anticancer agents compared to Doxorubicin: Design, Synthesis, SAR, In-silico and Toxicity Analysis

In order to determine whether thiazolobenzamide molecules connected to naphthalene could inhibit the growth of three different tumor cell lines, MCF7 (breast carcinoma), A549 (pulmonary carcinoma), and DU145 (prostatic adenocarcinoma) a novel series of ten molecules, designated TA 1-10, was designed, synthesized, and tested. Among these compounds, TA7 showed promising results against cell lines, especially showing exceptional efficacy against breast cancer. Antioxidant activity tests consistently showed the best performance from the TA7 molecule. Furthermore, when a dose of 50 to 500 mg/kg of the total mass of rats is given, the most effective chemical, TA7, did not exhibit any harmful effects during acute oral toxicity tests. The biochemical indicators (SGOT and SGPT) for hepatotoxicity associated with compound TA7 were found to be fairly similar to those of the control group. The findings from molecular docking, XP visualization, and MM-GBSA dG binding investigations are in agreement with the outcomes of in-vitro tests of antioxidant and anticancer capabilities. TA7 was the most effective compound among those that were docked; it bound free energy and had adequate properties for metabolism (biochemical processes), distribution (dispersion), absorption (assimilation), and excretion (elimination). This study found that the TA7 molecule, a thiazole ring system derivative connected to naphthalene, is to be a promising and possible anticancer agent and its efficacy may be further explored in clinical studies.

Synthesis of hydrazinylthiazole carboxylates: a mechanistic approach for treatment of diabetes and its complications

Aim: The deaths of thousands of people and millions affected by diabetes mellitus triggered us to look for alternative possible solutions to cure diabetes and its complications. Materials & methods: A series of hydrazinylthiazole carboxylates (3a-n) was prepared by cyclocondensation reaction of thiosemicarbazones with ethyl 2-chloroacetoacetate. These compounds were screened for antidiabetic potential through α-amylase inhibition, antiglycation and antioxidant assays. Results & conclusion: Most of the compounds exhibited a promising antidiabetic property. Compounds 3e and 3h showed excellent α-amylase and glycation inhibition properties. The hemolytic assay indicated that all compounds are biocompatible. Docking studies carried out on α-amylase target showed correlation between in vitro inhibition and binding energy.

Thiazole and Related Heterocyclic Systems as Anticancer Agents: A Review on Synthetic Strategies, Mechanisms of Action and SAR Studies

Background:

Cancer is the second leading cause of death throughout the world. Many anticancer drugs are commercially available, but lack of selectivity, target specificity, cytotoxicity and development of resistance lead to serious side effects. There have been several experiments going on to develop compounds with minor or no side effects.

Objective:

This review mainly emphasizes synthetic strategies, SAR studies, and mechanism of action for thiazole, benzothiazole, and imidazothiazole containing compounds as anticancer agents.

Methods:

Recent literature related to thiazole and thiazole-related derivatives endowed with encouraging anticancer potential is reviewed. This review emphasizes contemporary strategies used for the synthesis of thiazole and related derivatives, mechanistic targets, and comprehensive structural activity relationship studies to provide perspective into the rational design of high-efficiency thiazole-based anticancer drug candidates.

Results:

Exhaustive literature survey indicated that thiazole derivatives are associated with properties of inducing apoptosis and disturbing tubulin assembly. Thiazoles are also associated with the inhibition of NFkB/mTOR/PI3K/AkT and regulation of estrogen-mediated activity. Furthermore, thiazole derivatives have been found to modulate critical targets such as topoisomerase and HDAC.

Conclusion:

Thiazole derivatives seem to be quite competent and act through various mechanisms. Some of the thiazole derivatives, such as compounds 29, 40, 62, and 74a with IC50 values of 0.05 μM, 0.00042 μM, 0.18 μM, and 0.67 μM, respectively not only have anticancer activity but they also have lower toxicity and better absorption. Therefore, some other similar compounds could be investigated to aid in the development of anticancer pharmacophores.

Investigation of the Mechanisms of Cytotoxic Activity of 1,3-Disubstituted Thiourea Derivatives

Substituted thiourea derivatives possess confirmed cytotoxic activity towards cancer but also normal cells. To develop new selective antitumor agents, a series of 3-(trifluoromethyl)phenylthiourea analogs were synthesized, and their cytotoxicity was evaluated in vitro against the cell line panel. Compounds 1-5, 8, and 9 were highly cytotoxic against human colon (SW480, SW620) and prostate (PC3) cancer cells, and leukemia K-562 cell lines (IC₅₀ ≤ 10 µM), with favorable selectivity over normal HaCaT cells. The derivatives exerted better growth inhibitory profiles towards selected tumor cells than the reference cisplatin. Compounds incorporating 3,4-dichloro- (2) and 4-CF₃-phenyl (8) substituents displayed the highest activity (IC₅₀ from 1.5 to 8.9 µM). The mechanisms of cytotoxic action of the most effective thioureas 1-3, 8, and 9 were studied, including the trypan blue exclusion test of cell viability, interleukin-6, and apoptosis assessments. Compounds reduced all cancerous cell numbers (especially SW480 and SW620) by 20-93%. Derivatives 2 and 8 diminished the viability of SW620 cells by 45-58%. Thioureas 1, 2, and 8 exerted strong pro-apoptotic activity. Compound 2 induced late apoptosis in both colon cancer cell lines (95-99%) and in K-562 cells (73%). All derivatives acted as inhibitors of IL-6 levels in both SW480 and SW620 cells, decreasing its secretion by 23-63%.

Design and development of novel thiazole-sulfonamide derivatives as a protective agent against diabetic cataract in Wistar rats via inhibition of aldose reductase

In recent years, ALR2 (aldose reductase) inhibitors have attracted attention for their effective ability to reduce the progression of diabetes-associated cataracts. Therefore, in the present article, we intended to develop novel thiazole-sulfonamide hybrids as a potent inhibitor of ALR2. These molecules significantly inhibited the ALR2 level in the rat lenses homogenate, where the most potent compound 7b showed activity comparable to sorbinil as standard. In Wistar rats, compound 7b improved the insulin level and body weight of the experimental animal together with a reduction in the glucose output. Compound 7b showed a significant reduction in the expression of ALR2 in rat lenses in western blot analysis.

Hydrazonoyl bromide precursors as DHFR inhibitors for the synthesis of bis-thiazolyl pyrazole derivatives; antimicrobial activities, antibiofilm, and drug combination studies against MRSA

Microbial resistance is a big concern worldwide, making the development of new antimicrobial drugs difficult. The thiazole and pyrazole rings are important heterocyclic compounds utilized to produce a variety of antimicrobial medications. As a result, a series of new bis-thiazolyl-pyrazole derivatives 3, 4a-c, 5a, b, and 6a-c was synthesized by reacting bis hydrazonoyl bromide with several active methylene reagents in a one-pot reaction. The assigned structure was characterized entirely based on elemental and spectral analyses. The antimicrobial activity represented by MIC was performed using a resazurin-based turbidimetric (TB) assay. The results exhibited good antimicrobial activity against gram-positive strains, especially S. aureus (ATCC6538) while showing poor to moderate activity against gram-negative and fungal strains. Furthermore, the most active derivatives 3, 4a, 4c, and 5b were evaluated for MIC, MBC, antibiofilm, hemolytic assay, and drug combination testing against two S. aureus (ATCC6538) and MRSA (ACL18) strains. Additionally, bis-thiazolyl pyrazole 3, 4c, and 5b exhibited more potent inhibitory activity for DHFR with IC₅₀ values (6.34 ± 0.26, 7.49 ± 0.28, and 3.81 ± 0.16 µM), respectively, compared with Trimethoprim (8.34 ± 0.11 µM). The bis-1-(substituted-thiazol-2-yl)-1H-pyrazole-4-carbonitrile derivative 5b was the most active member with MIC values ranging from (0.12-0.25 µM) compared to Vancomycin (1-2 µM), and MBC values ranging from (0.5-1 µM) for S. aureus (ATCC6538) and MRSA (ACL18). Surprisingly, compound 5b displayed bactericidal behavior, synergistic effect with three commercial antibiotics, and inhibited DHFR with 2.1 folds higher than Trimethoprim. Finally, good findings were obtained from in silico investigations incorporating toxicity prediction and molecular docking simulation.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Novel Bis-Thiazole Derivatives: Synthesis and Potential Cytotoxic Activity Through Apoptosis With Molecular Docking Approaches

A series of bis-thiazoles 5a-g were synthesized from bis-thiosemicarbazone 3 with hydrazonoyl chlorides 4a-g. Reaction of 3 with two equivalents of α-halocarbonyl compounds 6-8, 10, and 12a-d afforded the corresponding bis-thiazolidines 9, 11, and 13a-d, respectively. Condensation of bis-thiazolidin-4-one 9 with different aromatic aldehydes furnished bis-thiazolidin-4-ones 14a-d. Compounds 5a-g, 9, and 13a,c,d were screened in vitro for their cytotoxic activities in a panel of cancer cell lines. Compounds 5a-c, 5f-g, and 9 exhibited remarkable cytotoxic activities, especially compound 5c with potent IC50 value 0.6 nM (against cervical cancer, Hela cell line) and compound 5f with high IC50 value 6 nM (against ovarian cancer, KF-28 cell line). Compound 5f-induced appreciated apoptotic cell death was measured as 82.76% associated with cell cycle arrest at the G1 phase. The apoptotic pathways activated in KF-28 cells treated with 5a, 5b, and 5f were further investigated. The upregulation of some pro-apoptotic genes, bax and puma, and the downregulation of some anti-apoptotic genes including the Bcl-2 gene were observed, indicating activation of the mitochondrial-dependent apoptosis. Together with the molecular docking studies of compounds 5a and 5b, our data revealed potential Pim-1 kinase inhibition through their high binding affinities indicated by inhibition of phosphorylated C-myc as a downstream target for Pim-1 kinase. Our study introduces a set of bis-thiazoles with potent anti-cancer activities, in vitro.

Synthesis, anticancer activity and mechanism of action of new phthalimido-1,3-thiazole derivatives

In this work, 22 new compounds were obtained and evaluated for their cytotoxic activity on peripheral blood mononuclear cells (PBMC) and eight different tumor cell lines. All compounds displayed IC₅₀ values above 100 μM when assayed against PBMCs. The cytotoxic assays in tumor cell lines revealed that sub-series of phthalimido-bis-1,3-thiazoles (5a-f) exhibited the best anti-tumor activity profile, presenting viability values below 59 %. As a result, the IC₅₀ value was calculated for compounds 5a-f and 4c, and compounds 5b and 5e were selected for further assays due to their best IC₅₀s. Considering the results presented by the sub-series 5a-f, the importance of the 1,3-thiazole ring in improving the anti-tumor activity was pointed out. Together, the results highlighted the anti-tumor activity of phthalimido-bis-1,3-thiazole derivatives.

QSAR, molecular docking and ADMET properties in silico studies of novel 4,5,6,7-tetrahydrobenzo[D]-thiazol-2-Yl derivatives derived from dimedone as potent anti-tumor agents through inhibition of C-Met receptor tyrosine kinase

A quantitative structure-activity relationship (QSAR) study is performed on 48 novel 4,5,6,7-tetrahydrobenzo[D]-thiazol-2 derivatives as anticancer agents capable of inhibiting c-Met receptor tyrosine kinase. The present study is conducted using multiple linear regression, multiple nonlinear regression and artificial neural networks. Three QSAR models are developed after partitioning the database into two sets (training and test) via the k-means method. The obtained values of the correlation coefficients by the three developed QSAR models are 0.90, 0.91 and 0.92, respectively. The resulting models are validated by using the external validation, leave-one-out cross-validation, Y-randomization test, and applicability domain methods. Moreover, we evaluated the drug-likeness properties of seven selected molecules based on their observed high activity to inhibit the c-Met receptor. The results of the evaluation showed that three of the seven compounds present drug-like characteristics. In order to identify the important active sites for the inhibition of the c-Met receptor responsible for the development of cancer cell lines, the crystallized form of the Crizotinib-c-Met complex (PDB code: 2WGJ) is used. These sites are used as references in the molecular docking test of the three selected molecules to identify the most suitable molecule for use as a new c-Met inhibitor. A comparative study is conducted based on the evaluation of the predicted properties of ADMET in silico between the candidate molecule and the Crizotinib inhibitor. The comparison results show that the selected molecule can be used as new anticancer drug candidates.

Antiproliferative activity of thiazole and oxazole derivatives: A systematic review of in vitro and in vivo studies

Thiazole and oxazole are compounds with a heterocyclic nucleus that have attracted the attention of medicinal chemistry due to the great variety of biological activities that they enable. In recent years, their study has increased, finding a wide range of biological activities, including antifungal, antiparasitic, anti-inflammatory, and anticancer activities. This systematic review provides evidence from the literature on the antiproliferative and antitumor activities of thiazole and oxazole and their derivatives from 2014 to April 2020. Three bibliographical databases were consulted (PubMed, Web of Science, and Scopus), and a total of 32 studies were included in this paper based on our eligibility criteria. The analysis of the activity-structure relationship allows us to conclude that most of the promising compounds identified contained thiazole nuclei or derivatives.

Thiazole Ring-A Biologically Active Scaffold

BACKGROUND

Thiazole is a good pharmacophore nucleus due to its various pharmaceutical applications. Its derivatives have a wide range of biological activities such as antioxidant, analgesic, and antimicrobial including antibacterial, antifungal, antimalarial, anticancer, antiallergic, antihypertensive, anti-inflammatory, and antipsychotic. Indeed, the thiazole scaffold is contained in more than 18 FDA-approved drugs as well as in numerous experimental drugs.

OBJECTIVE

To summarize recent literature on the biological activities of thiazole ring-containing compounds Methods: A literature survey regarding the topics from the year 2015 up to now was carried out. Older publications were not included, since they were previously analyzed in available peer reviews.

RESULTS

Nearly 124 research articles were found, critically analyzed, and arranged regarding the synthesis and biological activities of thiazoles derivatives in the last 5 years.

Design and Efficient Synthesis of Novel 4,5-Dimethylthiazole-Hydrazone Derivatives and their Anticancer Activity

Background::

Recently, researchers have been warning about the increased mortality of the various cancer types. Also, the lung adenocarcinoma and the glioma types are burning issues for world's health due to late or wrong diagnosis and/or insufficient treatment methods. For this purpose, our research group designed and synthesized novel 4,5-dimethyl thiazole-hydrazone derivatives which were tested against cancer and normal cell lines to understand the structureactivity relationship (SAR).

Method::

The lead compounds were obtained by reacting 2-(substituted aryl-2-ylmethylene) hydrazin-1-carbothioamide with 3-chloro-2-butanone derivatives. The structural elucidation of the compounds was performed by 1H-NMR, 13C-NMR, and LC/MS-IT-TOF spectral and elemental analyses. The synthesized compounds were tested in vitro for the anticancer activity against A549 human lung adenocarcinoma and C6 rat glioma cells and investigated for which pathway to induce cell death. Also, the docking study of the active compounds was achieved to understand the SAR.

Result and Discussion::

The targeted compounds (2a-2l) were synthesized successfully above 70% yields, and the analysis findings proved their purity. In general, the results of activity studies displayed significant effects against at least one cell line, except compounds 2e (indol-3-yl) and 2h (4-dimethylaminophenyl). Furthermore, compounds 2b and 2f displayed potential anticancer activity. With the help of molecular docking study, a potential selectivity of compound 2f was observed for type II protein kinase. On the other hand, compound 2b interacted with the active site nearly the same as Dasatinib. Therefore, these two compounds could be used as a base on developing selective anticancer drugs.

Conclusion::

Pyridin-2-yl (2b) derivative was found to be a favorable molecule with high anticancer potency against C6 and A549 cell lines. Additionally, 1-naphthyl (2f) derivative was a worthy compound for potential selectivity. In future studies, it will be our priority to focus on developing derivatives of these two compounds (2b and 2f) and elucidate their mechanisms.

An Overview of the Synthesis and Antimicrobial, Antiprotozoal, and Antitumor Activity of Thiazole and Bisthiazole Derivatives

Thiazole, a five-membered heteroaromatic ring, is an important scaffold of a large number of synthetic compounds. Its diverse pharmacological activity is reflected in many clinically approved thiazole-containing molecules, with an extensive range of biological activities, such as antibacterial, antifungal, antiviral, antihelmintic, antitumor, and anti-inflammatory effects. Due to its significance in the field of medicinal chemistry, numerous biologically active thiazole and bisthiazole derivatives have been reported in the scientific literature. The current review provides an overview of different methods for the synthesis of thiazole and bisthiazole derivatives and describes various compounds bearing a thiazole and bisthiazole moiety possessing antibacterial, antifungal, antiprotozoal, and antitumor activity, encouraging further research on the discovery of thiazole-containing drugs.

Synthesis, characterization, crystal structures, and the biological evaluation of 2-phenylthiazole derivatives as cholinesterase inhibitors

Four 2-phenylthiazole derivatives are synthesized, characterized, and evaluated as cholinesterase inhibitors. The structures of the 2-phenylthiazole derivatives are confirmed by 1H and 13C nuclear magnetic resonance spectroscopy, single-crystal X-ray diffraction studies, and Hirshfeld surfaces analysis. Hirshfeld surface analysis of the prepared compounds showed C–H···O intermolecular interactions. The cholinesterase inhibition activities of the synthesized compounds are tested by Ellman’s method. [2-(4-Benzyloxyphenyl)-thiazol-4-yl]-(3,5-dimethylpiperidin-1-yl)-methanone showed the best acetylcholinesterase inhibition activity with an IC50 value of 8.86 µM and the best butyrylcholinesterase inhibition activity with an IC50 value of 1.03 µM. A docking study demonstrates that the same compound interacts with the catalytic anionic site and peripheral anionic site of acetylcholinesterase and the catalytic anionic site of butyrylcholinesterase.

Synthesis and Evaluation of Antimicrobial Activity and Molecular Docking of New N-1,3-thiazol-2-ylacetamides of Condensed Pyrido[3',2':4,5] furo(thieno)[3,2-d]pyrimidines

Background:

From the literature it is known that many derivatives of fused thienopyrimidines and furopyrimidines possess broad spectrum of biological activity.

Objectives:

The current studies describe the synthesis and evaluation of antimicrobial activity of some new N-1,3-thiazol-2-ylacetamides of pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidines.

Methods:

By cyclocondensation of ethyl 1-aminofuro(thieno)[2,3-b]pyridine-2-carboxylates 1with formamide were converted to the pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidin-7(8)-ones 2.Alkylation of compound 2 with 2-chloro-N-1,3-thiazol-2-ylacetamide led to the aimed N-1,3-thiazol-2-ylaceta-mides of pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidines 3. Starting from compound 2 the relevant S-alkylated derivatives of pyrido[3',2':4,5]furo(thieno)[3,2-d]pyrimidines 6 were also synthesized.

Results:

All the compounds showed antibacterial activity to non-resistant strains. Compounds 3a-3m showed antibacterial activity with MIC/MBC at 0.08-2.31 mg/mL/0.11-3.75 mg/mL .The two most active compounds, 3j and 6b, appeared to be more active towards MRSA than the reference drugs. Half of the tested compounds appeared to be equipotent/more potent than ketoconazole and more potent than bifonazole. The docking analysis provided useful information about the interactions occurring between the tested compounds and the different enzymes.

Conclusion:

Gram-negative and Gram-positive bacteria and fungi showed different response towards tested compounds, indicating that different substituents may lead to different modes of action or that the metabolism of some bacteria/fungi was better able to overcome the effect of the compounds or adapt to it.

Design, Synthesis, In vitro and In silico Evaluation of New Hydrazonebased Antitumor Agents as Potent Akt Inhibitors

Background:

Akt is overexpressed or activated in a variety of human cancers, including gliomas, lung, breast, ovarian, gastric and pancreatic carcinomas. Akt inhibition leads to the induction of apoptosis and inhibition of tumor growth and therefore extensive efforts have been devoted to the discovery of potent antitumor drugs targeting Akt.

Objectives:

The objective of this work was to identify potent anticancer agents targeting Akt.

Methods:

New hydrazone derivatives were synthesized and investigated for their cytotoxic effects on 5RP7 H-ras oncogene transformed rat embryonic fibroblast and L929 mouse embryonic fibroblast cell lines. Besides, the apoptotic effects of the most active compounds on 5RP7 cell line were evaluated using flow cytometry. Their Akt inhibitory effects were also investigated using a colorimetric assay. In silico docking and Absorption, Distribution, Metabolism and Excretion (ADME) studies were also performed using Schrödinger’s Maestro molecular modeling package.

Results and Discussion:

Compounds 3a, 3d, 3g and 3j were found to be effective on 5RP7 cells (with IC50 values of <0.97, <0.97, 1.13±0.06 and <0.97 μg/mL, respectively) when compared with cisplatin (IC50= 1.87±0.15 μg/mL). It was determined that these four compounds significantly induced apoptosis in 5RP7 cell line. Among them, N'-benzylidene-2-[(4-(4-methoxyphenyl)pyrimidin- 2-yl)thio]acetohydrazide (3g) significantly inhibited Akt (IC50= 0.5±0.08 μg/mL) when compared with GSK690693 (IC50= 0.6±0.05 μg/mL). Docking studies suggested that compound 3g showed good affinity to the active site of Akt (PDB code: 2JDO). According to in silico ADME studies, the compound also complies with Lipinski's rule of five and Jorgensen's rule of three.

Conclusion:

Compound 3g stands out as a potential orally bioavailable cytotoxic agent and apoptosis inducer targeting Akt.

Antiglioma Activity of Aryl and Amido-Aryl Acetamidine Derivatives Targeting iNOS: Synthesis and Biological Evaluation

Nitric oxide is an important inflammation mediator with a recognized role in the development of different cancers. Gliomas are primary tumors of the central nervous system with poor prognosis, and the expression of the inducible nitric oxide synthase correlates with the degree of malignancy, changes in vascular reactivity, and neo-angiogenesis. Therefore, targeting the nitric oxide biosynthesis appears as a potential strategy to impair glioma progression. In the present work a set of aryl and amido-aryl acetamidine derivatives were synthesized to obtain new potent and selective inducible nitric oxide synthase inhibitors with improved physicochemical parameters with respect to the previously published molecules. Compound 17 emerged as the most promising inhibitor and was evaluated on C6 rat glioma cell line, showing antiproliferative effects and high selectivity over astrocytes.

New Hybrids Derived from the Natural Compound (-)-β-Pinene and Amides or Acylthioureas as Antitumor Agents

Background:

Plant-derived natural compounds have a unique molecular structure and rich biological activity, hence, they are treated as important raw materials for the development of drugs.

Methods:

A natural compound (-)-β-pinene was used as a raw material, and twenty-six novel derivatives with amide or acylthiourea groups were synthesized based on the molecular hybridization method. In vitro antitumor activity of these derivatives on human breast cancer cell line MCF7 and human colon cancer cell line SW1116 were tested by MTT method. The effects of the synthesized derivatives on the morphology of MCF7 and SW1116 were observed by fluorescent inverted microscope.

Results:

The preliminary structure-activity relationship analysis demonstrates that the position and species of substituents on the aromatic ring of derivatives have an effect on the antitumor activity of derivatives. Observation of the cell morphology reveals that derivatives with antitumor activity can lead to rounding of the cell morphology, a decrease in cell volume and cell density, and ultimately inhibition of the proliferation of MCF7 and SW1116 cells. The antitumor activity evaluation results show that among these derivatives, compounds 5c, 5e, 5h, 7c, 7b and 7e exhibit good antitumor activity against MCF7, and compounds 5c, 5e, 5h and 7j exert moderate antitumor activity against SW1116.

Conclusion:

This study hopes to promote the high value-added utilization of natural compounds β-pinene and the development of novel antitumor drugs.

Design, Synthesis, Evaluation of Antimicrobial Activity and Docking Studies of New Thiazole-based Chalcones

BACKGROUND

Thiazole derivates as well as chalcones, are very important scaffold for medicinal chemistry. Literature survey revealed that they possess wide spectrum of biological activities among which are anti-inflammatory and antimicrobial.

OBJECTIVES

The current studies describe the synthesis and evaluation of antimicrobial activity of twenty eight novel thiazole-based chalcones.

METHODS

The designed compounds were synthesized using classical methods of organic synthesis. The in vivo evaluation of antimicrobial activity was performed by microdilution method.

RESULTS

All compounds have shown antibacterial properties better than that of ampicillin and in many cases better than streptomycin. As far as the antifungal activity is concerned, all compounds possess much higher activity than reference drugs bifonazole and ketoconazole. The most sensitive bacterial species was B. cereus (MIC 6.5-28.4 µmol × 10-2/mL and MBC 14.2-105.0 µmol × 10-2/mL) while the most resistant ones were L. monocytogenes (MIC 21.4-113.6 µmol × 10-2/mL) and E. coli (MIC 10.7- 113.6 µmol × 10-2/mL) and MBC at 42.7-358.6 µmol × 10-2/mL and 21.4-247.2 µmol × 10-2/mL, respectively. All the compounds exhibited antibacterial activity against the three resistant strains, MRSA, P. aeruginosa and E.coli. with MIC and MBC in the range of 0.65-11.00 µmol/mL × 10-2 and 1.30-16.50 µmol/mL × 10-2. Docking studies were performed.

CONCLUSION

Twenty-eight novel thiazole-based chalcones were designed, synthesized and evaluated for antimicrobial activity. The results showed that these derivatives could be lead compounds in search of new potent antimicrobial agents. Docking studies indicated that DNA gyrase, GyrB and MurA inhibition may explain the antibacterial activity.

A Brief Literature and Review of Patents on Thiazole Related Derivatives

Background:

Thiazole is widely investigated bioactive scaffold and dynamic tool in medicinal chemistry research. Significance of thiazole compounds are well documented as thiazole is an obligatory structure of number of currently available therapeutics. In spite of that, thiazole derivatives are endowed with myriad biological activities, such as antiviral, anticancer, antibacterial, antifungal, antimalarial, antiparkinsonian, anti-inflammatory activities and many more.

Methods:

In recent past, different approaches have been introduced for synthesis of thiazole and related compounds. Intrinsic molecular interaction between newly synthesized thiazole compounds and plethora of drug targets/enzymes has rendered discovery of new drug molecules with advances in modes of action. A renewed interest in therapeutic use of thiazole derivatives has been seen among the prospective researchers as exemplified by influx of huge scientific articles and patents. Some important patents of anti-infective and anticancer interest have been addressed appropriately and are presented in tables.

Results:

This review paper is a contemporary approach on therapeutic/applications of thiazole derivatives by summarizing important patents filed from 2000-2017. The main focus of these patents is on anti-infective and anticancer potential of thiazole based compounds.

Conclusion:

These approaches may provide valuable information for the further design of more active biological agents through various modifications and derivatizations.

New Series of Thiazole Derivatives: Synthesis, Structural Elucidation, Antimicrobial Activity, Molecular Modeling and MOE Docking

Based on the extensive biological activities of thiazole derivatives against different types of diseases, we are interested in the effective part of many natural compounds, so we synthesized a new series of compounds containing di-, tri- and tetrathiazole moieties. The formation of such derivatives proceeded via reaction of 2-bromo-1-(4-methyl-2-(methylamino)thiazol-5-yl)ethan-1-one with heterocyclic amines, o-aminothiophenol and thiosemicarbazone derivatives. The structure and mechanistic pathways for all products were discussed and proved based on spectral results, in addition to conformational studies. Our aim after the synthesis is to investigate their antimicrobial activity against various types of bacteria and fungi species. Preceeding such an investigation, a molecular docking study was carried out with selected conformers, as representative examples, against three pathogen-proteins. This preliminary stage could support the biological application. The potency of these compounds as antimicrobial agents has been evaluated. The results showed that derivatives which have di- and trithiazole rings displayed high activity that exceeds the used standard antibiotic.

A Review Exploring Therapeutic Worth of 1,3,4-Oxadiazole Tailored Compounds

1,3,4-Oxadiazole, a five-membered aromatic ring can be seen in a number of synthetic molecules. The peculiar structural feature of 1,3,4-oxadiazole ring with pyridine type of nitrogen atom is beneficial for 1,3,4-oxadiazole derivatives to have effective binding with different enzymes and receptors in biological systems through numerous weak interactions, thereby eliciting an array of bioactivities. Research in the area of development of 1,3,4-oxadiazole-based derivatives has become an interesting topic for the scientists. A number of 1,3,4-oxadiazole based compounds with high therapeutic potency are being extensively used for the treatment of different ailments, contributing to enormous development value. This work provides a systematic and comprehensive review highlighting current developments of 1,3,4-oxadiazole based compounds in the entire range of medicinal chemistry such as anticancer, antifungal, antibacterial, antitubercular, anti-inflammatory, antineuropathic, antihypertensive, antihistaminic, antiparasitic, antiobesity, antiviral, and other medicinal agents. It is believed that this review will be of great help for new thoughts in the pursuit for rational designs for the development of more active and less toxic 1,3,4-oxadiazole based medicinal agents.

A Review on Recent Synthetic Strategies and Pharmacological Importance of 1,3-Thiazole Derivatives

Thiazole is the most common heterocyclic compound in heterocyclic chemistry and in drug design. Presence of several reaction sites in the thiazole moiety extends their range of applications and leads to new solutions for challenges in synthetic and medicinal chemistry. Thiazole derivatives are widely used as bioactive agents, liquid crystals, sensors, catalysts, etc. The motivating molecular architecture of 1,3-thiazoles makes them suitable moieties for drug development. In this review, our aim is to corroborate the recent data available on various synthetic strategies and biological properties of 1,3- thiazole derivatives.

Synthesis and Evaluation of a New Series of Thiazolyl-pyrazoline Derivatives as Cholinesterase Inhibitors

Objectives

In recent years, the design of anticholinesterase agents based on molecular hybridization of pharmacologically active scaffolds has attracted a great deal of interest in medicinal chemistry. For this purpose, we aimed to design and synthesize anticholinesterase agents based on the molecular hybridization of thiazole and pyrazoline scaffolds.

Materials and Methods

New thiazolyl-pyrazoline derivatives were synthesized via the ring closure reaction of 3-(2-furyl)-5-(1,3-benzodioxol-5-yl)-1-thiocarbamoyl-4,5-dihydro-1H-pyrazole with 2-bromo-1-arylethanone derivatives. The compounds were investigated for their inhibitory effects on AChE and BuChE using a modification of Ellman's spectrophotometric method. As a part of this study, the compliance of the compounds to Lipinski's rule of five was evaluated. The physicochemical parameters (log P, TPSA, nrotb, molecular weight, number of hydrogen bond donors and acceptors, molecular volume) were calculated using Molinspiration software.

Results

2-[5-(1,3-Benzodioxol-5-yl)-3-(2-furyl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(naphthalen-2-yl)thiazole was found to be the most effective AChE inhibitor (38.5±2.85%), whereas 2-[5-(1,3-benzodioxol-5-yl)-3-(2-furyl)-4,5-dihydro-1H-pyrazol-1-yl]-4-(4-fluorophenyl)thiazole was found as the most potent BuChE inhibitor (43.02±2.71%) in this series. These compounds only violated one parameter of Lipinski's rule of five. On the basis of Lipinski's rule, they were expected to have reasonable oral bioavailability.

Conclusion

In the view of this study, the structural modification of the identified compounds is on-going for the generation of new cholinesterase inhibitors with enhanced efficacy.

Thiazole, thio and semicarbazone derivatives against tropical infective diseases: Chagas disease, human African trypanosomiasis (HAT), leishmaniasis, and malaria

Thiazole, thiosemicarbazone and semicarbazone moieties are privileged scaffolds (acting as primary pharmacophores) in many compounds that are useful to treat several diseases, mainly tropical infectious diseases. In this review article, we critically analyzed the contribution of these scaffolds to medicinal chemistry in the last five years, focusing on tropical infectious diseases, such as Chagas disease, human African trypanosomiasis (HAT), leishmaniasis, and malaria. We also present perspectives for their use in drug design in order to contribute to the development of new drugs.

Discovery of novel human inosine 5'-monophosphate dehydrogenase 2 (hIMPDH2) inhibitors as potential anticancer agents

The enzyme inosine 5'-monophosphate dehydrogenase (IMPDH) catalyzes an essential step in the de novo biosynthesis of guanine nucleotides, and thus regulates the guanine nucleotide pool required for cell proliferation. Of the two isoforms, human IMPDH type 2 (hIMPDH2) is a validated molecular target for potential immunosuppressive, antiviral and anticancer chemotherapy. In search of newer hIMPDH2 inhibitors as potential anticancer agents, three novel series (A: 5-aminoisobenzofuran-1(3H)-one, B: 3,4-dimethoxyaniline and C: benzo[d]-[1,3]dioxol-5-ylmethanamine) were synthesized and evaluated for in vitro and cell-based activities. A total of 37 molecules (29-65) were screened for their in vitro hIMPDH2 inhibition, with particular emphasis on establishing their structure-activity relationship (SAR) trends. Eight compounds (hits, 30, 31, 33-35, 37, 41 and 43) demonstrated significant enzyme inhibition (>70% @ 10 μM); especially the A series molecules were more potent than B series (<70% inhibition @ 10 μM), while C series members were found to be inactive. The hIMPDH2 IC50 values for the hits ranged from 0.36 to 7.38 μM. The hits displaying >80% hIMPDH2 inhibition (30, 33, 35, 41 and 43) were further assessed for their cytotoxic activity against cancer cell lines such as MDA-MB-231 (breast adenocarcinoma), DU145 (prostate carcinoma), U87 MG (glioblastoma astrocytoma) and a normal cell line, NIH-3T3 (mouse embryonic fibroblast) using MTT assay. Most of the compounds exhibited higher cellular potency against cancer cell lines and notably lower toxicity towards NIH-3T3 cells compared to mycophenolic acid (MPA), a prototypical hIMPDH2 inhibitor. Two of the series A hits (30 and 35) were evaluated in human peripheral blood mononuclear cells (hPBMC) assay and found to be better tolerated than MPA. The calculated/predicted molecular and physicochemical properties were satisfactory with reference to drug-likeness. The molecular docking studies clearly demonstrated crucial interactions of the hits with the cofactor-binding site of hIMPDH2, further providing critical information for refining the design strategy. The present study reports the design and discovery of structurally novel hIMPDH2 inhibitors as potential anticancer agents and provides a guide for further research on the development of safe and effective anticancer agents, especially against glioblastoma.

Disubstituted 4-Chloro-3-nitrophenylthiourea Derivatives: Antimicrobial and Cytotoxic Studies

4-Chloro-3-nitrophenylthioureas 1–30 were synthesized and tested for their antimicrobial and cytotoxic activities. Compounds exhibited high to moderate antistaphylococcal activity against both standard and clinical strains (MIC values 2–64 μg/mL). Among them derivatives with electron-donating alkyl substituents at the phenyl ring were the most promising. Moreover, compounds 1–6 and 8–19 were cytotoxic against MT-4 cells and various other cell lines derived from human hematological tumors (CC₅₀ ≤ 10 μM). The influence of derivatives 11, 13 and 25 on viability, mortality and the growth rate of immortalized human keratinocytes (HaCaT) was observed.