Design and synthesis of novel 4-benzothiazole amino quinazolines Dasatinib derivatives as potential anti-tumor agents

Benzothiazole derivatives in the design of antitumor agents

Benzothiazoles are a class of heterocycles with multiple applications as anticancer, antibiotic, antiviral, and anti-inflammatory agents. Benzothiazole is a privileged scaffold in drug discovery programs for modulating a variety of biological functions. This review focuses on the design and synthesis of new benzothiazole derivatives targeting hypoxic tumors. Cancer is a major health problem, being among the leading causes of death. Tumor-hypoxic areas promote proliferation, malignancy, and resistance to drug treatment, leading to the dysregulation of key signaling pathways that involve drug targets such as vascular endothelial growth factor, epidermal growth factor receptor, hepatocyte growth factor receptor, dual-specificity protein kinase, cyclin-dependent protein kinases, casein kinase 2, Rho-related coil formation protein kinase, tunica interna endothelial cell kinase, cyclooxygenase-2, adenosine kinase, lysophosphatidic acid acyltransferases, stearoyl-CoA desaturase, peroxisome proliferator-activated receptors, thioredoxin, heat shock proteins, and carbonic anhydrase IX/XII. In turn, they regulate angiogenesis, proliferation, differentiation, and cell survival, controlling the cell cycle, inflammation, the immune system, and metabolic alterations. A wide diversity of benzothiazoles were reported over the last years to interfere with various proteins involved in tumorigenesis and, more specifically, in hypoxic tumors. Many hypoxic targets are overexpressed as a result of the hypoxia-inducible factor activation cascade and may not be present in normal tissues, providing a potential strategy for selectively targeting hypoxic cancers.

Synthesis, In vivo, and In silico Evaluation of New Pyrazoline-Benzothiazole Conjugates as Antiepileptic Agents

New 2-(4-benzothiazol-2-yl-phenoxy)-1-(3,5-diphenyl-4,5-dihydro-pyrazol-1-yl)-ethanones (9a-o) have been designed and synthesized. All the synthesized compounds were characterized by thin layer chromatography and spectral analysis. The antiepileptic potential of the synthesized compounds has been tested by following standard animal screening models, including maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) models. The neurotoxic and antidepression effects of the synthesized compounds were checked by utilizing rotarod apparatus, and motor impairment test (by actophotometer) respectively. The study concluded that compounds 9c, 9d, 9f, 9i, 9n, and 9o possessed good antiepileptic potential compared to standard drugs like carbamazepine and phenytoin. The results of the rotarod performance test also established them without any neurotoxicity. The motor impairment test revealed that the synthesized compounds are also good antidepressants. In-silico studies have been performed for calculation of pharmacophore pattern, prediction of pharmacokinetic properties which determine the eligibility of synthesized compounds as orally administered molecules and interactions with the target proteins. The result of in-silico studies reinforced results obtained by in vivo study of the synthesized compounds and their possible mechanism of antiepileptic action i. e. via inhibiting voltage-gated sodium channels (VGSCs) and gamma-aminobutyric acid-A receptor.

Novel 2-Aminobenzothiazole Derivatives: Docking, Synthesis, and Biological Evaluation as Anticancer Agents

Sixteen novel 2-aminobenzothiazole compounds with different amines or substituted piperazine moieties were designed, synthesized, and tested using various methods. Potential interactions were assessed by docking new compounds in the adenosine triphosphate (ATP) binding domain of the PI3Kγ enzyme (PDB code: 7JWE) by nucleophilic substitution or solvent-free/neat fusion for docked compound synthesis. Final 2-aminobenzothiazole compounds were characterized by direct probe gas chromatography-mass spectrometry (GC-MS), proton (1H-NMR), carbon-13 (13C-NMR), and attenuated total reflectance-infrared Fourier transform infrared (ATR FT-IR). The synthesized compounds were investigated for anticancer activities on lung cancer (A549) and breast cancer (MCF-7) cell lines. The compounds' PI3Kγ inhibition was evaluated at a 100 μM concentration. 4-Nitroaniline and piperazine-4-nitroaniline combination in OMS5 and OMS14 reduced lung and breast cancer cell line growth. IC50 values for OMS5 and OMS14, the strongest compounds, ranged from 22.13 to 61.03 μM. OMS1 and OMS2 inhibited PI3Kγ at the highest rates (47 and 48%, respectively) at a 100 μM concentration. Results show that the PI3Kγ enzyme suppression is not the main mechanism behind these OMS5 and OMS14 anticancer effects. CDK2, Akt, mTOR, and p42/44 MAPK are affected. EGF receptor suppression matters. AKT1, AKT3, CDK1/cyclin B, PDK1 direct, PIK3CA E542 K/PIK3R1 (p110 α/p85 α), PIK3CD/PIK3R1 (p110 δ/p85 α), and PKN inhibition were measured to evaluate the possible mechanism of compound OMS14. PIK3CD/PIK3R1 (p110 δ/p85 α) is the most, with 65% inhibition, suggesting a possible mechanism of anticancer properties. Furthermore, the NCI 60-cell line inhibition demonstrates promising broad anticancer inhibition against numerous cancer cell lines of OMS5 and OMS14, which could be good lead compounds for future development.

Explanatory review on pyrimidine/fused pyrimidine derivatives as anticancer agents targeting Src kinase

The pyrimidine and fused pyrimidine ring systems play vital roles to inhibit the c-Src kinase. The Src kinase is made of different domains but the kinase domain is responsible for inhibition of Src kinase. In which the kinase domain is the main domain that is made of several amino acids. The Src kinase is inhibited by its inhibitors when it is activated by phosphorylation. Although dysregulation of Src kinase caused cancer in the late nineteenth century, medicinal chemists have not explored it extensively; therefore it is still regarded as a cult pathway. There are numerous FDA-approved drugs on the market, yet novel anticancer drugs are still in demand. Existing medications have adverse effects and drug resistance owing to rapid protein mutation. In this review, we discussed the activation process of Src kinase, chemistry of pyrimidine ring and its different synthetic routes, as well as the recent development in c-Src kinase inhibitors containing pyrimidine and their biological activity, SAR, and selectivity. The c-Src binding pocket has been predicted in detail to discover the vital amino acids which will interact with inhibitors. The potent derivatives were docked to discover the binding pattern. The derivative 2 established three hydrogen bonds with the amino acid residues Thr341 and Gln278 and had the greatest binding energy of -13.0 kcal/mol. The top docked molecules were further studied for ADMET studies. The derivative 1, 2, and 43 did not show any violation of Lipinski's rule. All derivatives used for the prediction of toxicity showed toxicity.

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

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

Medicinal Chemistry Perspectives on Recent Advances in Src Kinase Inhibitors as a Potential Target for the Development of Anticancer Agents: Biological Profile, Selectivity, Structure-Activity Relationship

The physiological Src proto-oncogene is a protein tyrosine kinase receptor that served as the essential signaling pathway in different types of cancer. Src kinase receptor is divided into different domains: a unique domain, an SH3 domain, an SH2 domain, a protein tyrosine kinase domain, and a regulatory tail, which runs from the N-terminus to the C-terminus. Src kinase inhibitors bind in the kinase domain and are activated by phosphorylation. The etiology of cancer involved various signaling pathways and Src signaling pathways are also involved in those clusters. Although the dysregulation of Src kinase resulted in cancer being discovered in the late 19th century it is still considered a cult pathway because it is not much explored by different medicinal chemists and oncologists. The Src kinase regulated through different kinase pathways (MAPK, PI3K/Akt/mTOR, JAK/STAT3, Hippo kinase, PEAK1, and Rho/ROCK pathways) and proceeded downstream signaling to conduct cell proliferation, angiogenesis, migration, invasion, and metastasis of cancer cells. There are numerous FDA-approved drugs flooded the market but still, there is a huge demand for the creation of novel anticancer drugs. As the existing drugs are accompanied by several adverse effects and drug resistance due to rapid mutation in proteins. In this review, we have elaborated about the structure and activation of Src kinase, as well as the development of Src kinase inhibitors. Our group also provided a comprehensive overview of Src inhibitors throughout the last two decades, including their biological activity, structure-activity relationship, and Src kinase selectivity. The Src binding pocket has been investigated in detail to better comprehend the interaction of Src inhibitors with amino acid residues. We have strengthened the literature with our contribution in terms of molecular docking and ADMET studies of top compounds. We hope that the current analysis will be a useful resource for researchers and provide glimpse of direction toward the design and development of more specific, selective, and potent Src kinase inhibitors.

Structure-Activity Relationship Studies Based on Quinazoline Derivatives as EGFR Kinase Inhibitors (2017-Present)

The epidermal growth factor receptor (EGFR) plays a critical role in the tumorigenesis of various forms of cancer. Targeting the mutant forms of EGFR has been identified as an attractive therapeutic approach and led to the approval of three generations of inhibitors. The quinazoline core has emerged as a favorable scaffold for the development of novel EGFR inhibitors due to increased affinity for the active site of EGFR kinase. Currently, there are five first-generation (gefitinib, erlotinib, lapatinib, vandetanib, and icotinib) and two second-generation (afatinib and dacomitinib) quinazoline-based EGFR inhibitors approved for the treatment of various types of cancers. The aim of this review is to outline the structural modulations favorable for the inhibitory activity toward both common mutant (del19 and L858R) and resistance-conferring mutant (T790M and C797S) EGFR forms, and provide an overview of the newly synthesized quinazoline derivatives as potentially competitive, covalent or allosteric inhibitors of EGFR.

Medicinal Chemistry of Quinazolines as Anticancer Agents Targeting Tyrosine Kinases

Cancer is a large group of diseases that can affect any organ or body tissue due to the abnormal cellular growth with the unknown reasons. Many of the existing chemotherapeutic agents are highly toxic with a low level of selectivity. Additionally, they lead to development of therapeutic resistance. Hence, the development of targeted chemotherapeutic agents with low side effects and high selectivity is required for cancer treatment. Quinazoline is a vital scaffold well-known to be linked with several biological activities. The anticancer activity is one of the prominent biological activities of this scaffold. Several established anticancer quinazolines work by different mechanisms on the various molecular targets. The aim of this review is to present different features of medicinal chemistry as drug design, structure activity relationship, and mode of action of some targeted anticancer quinazoline derivatives. It gives comprehensive attention on the chemotherapeutic activity of quinazolines in the viewpoint of drug discovery and its development. This review provides panoramic view to the medicinal chemists for supporting their efforts to design and synthesize novel quinazolines as targeted chemotherapeutic agents.

Pyridine appended 2-hydrazinylthiazole derivatives: design, synthesis, in vitro and in silico antimycobacterial studies

An array of pyridine appended 2-hydrazinylthiazole derivatives has been synthesized to discover novel chemotherapeutic agents for Mycobacterium tuberculosis (Mtb). The drug-likeness of pyridine appended 2-hydrazinylthiazole derivatives was validated using the Lipinski and Veber rules. The designed thiazole molecules have been synthesized through Hantzsch thiazole methodologies. The in vitro antimycobacterial studies have been conducted using Luciferase reporter phage (LRP) assay. Out of thirty pyridine appended 2-hydrazinylthiazole derivatives, the compounds 2b, 3b, 5b, and 8b have exhibited good antimycobacterial activity against Mtb, an H37Rv strain with the minimum inhibitory concentration in the range of 6.40–7.14 μM. In addition, in vitro cytotoxicity of active molecules has been observed against Human Embryonic Kidney Cell lines (HEK293t) using MTT assay. The compounds 3b and 8b are nontoxic and their cell viability is 87% and 96.71% respectively. The in silico analyses of the pyridine appended 2-hydrazinylthiazole derivatives have been studied to find the mode of binding of the active compounds with KasA protein of Mtb. The active compounds showed a strong binding score (−5.27 to −6.23 kcal mol⁻¹).

Thirty novel pyridine-appended 2-hydrazinylthiazole derivatives have been synthesized and tested for their antimycobacterial activity against Mictrobactrium tuberculosis, H37Rv strain.

Synthetic and Medicinal Perspective of Fused-Thiazoles as Anticancer Agents

BACKGROUND

Cancer is second leading disease after cardiovascular disease. Presently, Chemotherapy, Radiotherapy and use of chemicals are some treatments available these days. Thiazole and its hybrid compounds extensively used scaffolds in drug designing and development of novel anticancer agents due to their wide pharmacological profiles. Fused thiazole scaffold containing drugs are available in market as a promising group of anticancer agents.

METHODS

The detailed study has been done using different database that focused on potent thiazole hybrid compounds with anticancer activity. The literature included in this review is focused on novel fused thiazole derivatives exhibiting anticancer potency in last decade.

RESULTS

Literature suggested that thiazoles and its fused and linked congener serve excellent pharmacological profile as an anticancer agent. Various synthetic strategies for fused thiazole are also summarized in this article. Novel thiazole and its fused congener showed anticancer activity against various cancer cell lines.

INTERPRETATION

Thiazole is a promising scaffold reported in literature with broad range of biological activities. This article covers the thiazole compounds fused with other carbocyclic/heterocycle including benzene, imidazole, pyridine, pyrimidine, quinoline, phenothiazine, thiopyrano, steroids, pyrrole etc. with anticancer activity from last decades. Several inhibitors for breast cancer, colon cancer, melanoma cancer, ovarian cancer, tubulin cancer etc. were reported in this review. Thus, this review will definitely aid to develop a lead for the new selective anticancer agents in future.

The Novel Benzothiazole Derivative PB11 Induces Apoptosis via the PI3K/AKT Signaling Pathway in Human Cancer Cell Lines

Among several anti-cancer therapies, chemotherapy can be used regardless of the stage of the disease. However, development of anti-cancer agents from potential chemicals must be executed very cautiously because of several problems, such as safety, drug resistance, and continuous administration. Most chemotherapeutics selectively cause cancer cells to undergo apoptosis. In this study, we tested the effects of a novel chemical, the benzothiazole derivative N-[2-[(3,5-dimethyl-1,2-oxazol-4-yl)methylsulfanyl]-1,3-benzothiazol-6-yl]-4-oxocyclohexane-1-carboxamide (PB11) on the human cell lines U87 (glioblastoma), and HeLa (cervix cancer). It was observed that this chemical was highly cytotoxic for these cells (IC50s < 50 nM). In addition, even 40 nM PB11 induced the classical apoptotic symptoms of DNA fragmentation and nuclear condensation. The increase of caspase-3 and -9 activities also indicated an increased rate of apoptosis, which was further confirmed via Western blotting analysis of apoptosis-associated proteins. Accordingly, PB11 treatment up-regulated the cellular levels of caspase-3 and cytochrome-c, whereas it down-regulated PI3K and AKT. These results suggest that PB11 induces cytotoxicity and apoptosis in cancer cells by suppressing the PI3K/AKT signaling pathways and, thus, may serve as an anti-cancer therapeutic.

Benzothiazole derivatives as anticancer agents

Benzothiazole (BTA) belongs to the heterocyclic class of bicyclic compounds. BTA derivatives possesses broad spectrum biological activities such as anticancer, antioxidant, anti-inflammatory, anti-tumour, antiviral, antibacterial, anti-proliferative, anti-diabetic, anti-convulsant, analgesic, anti-tubercular, antimalarial, anti-leishmanial, anti-histaminic and anti-fungal among others. The BTA scaffolds showed a crucial role in the inhibition of the metalloenzyme carbonic anhydrase (CA). In this review an extensive literature survey over the last decade discloses the role of BTA derivatives mainly as anticancer agents. Such compounds are effective against various types of cancer cell lines through a multitude of mechanisms, some of which are poorly studied or understood. The inhibition of tumour associated CAs by BTA derivatives is on the other hand better investigated and such compounds may serve as anticancer leads for the development of agents effective against hypoxic tumours.

Therapeutic progression of quinazolines as targeted chemotherapeutic agents

Presently cancer is a grave health issue with predominance beyond restrictions. It can affect any organ of the body. Most of the available chemotherapeutic drugs are highly toxic, not much selective and eventually lead to the development of resistance. Therefore, a target specific palliative approach for the treatment of cancer is required. Remarkable advancements in science have illuminated various molecular pathways responsible for cancer. This has resulted in abundant opportunities to develop targeted anticancer agents. Quinazoline nucleus is a privileged scaffold with significant diversified pharmacological activities. Numerous established anticancer quinazoline derivatives constitute a new class of chemotherapeutic agents which are found to act by inhibiting various protein kinases as well as other molecular targets. A recent update on various quinazoline derivatives acting on different types of molecular targets for the treatment of cancer has been compiled in this review. Brief SAR studies of quinazoline derivatives acting through different mechanisms of action have been highlighted. The comprehensive medicinal chemistry aspects of these agents in this review provide a panoramic view to the biologists as well as medicinal chemists working in this area and would assist them in their efforts to design and synthesize novel quinazoline based anticancer compounds.

2-Aminothiazole: A privileged scaffold for the discovery of anti-cancer agents

Cancer has been the second heath killer being next only to cardiovascular diseases in human society. Although many efforts have been taken for cancer therapy and many achievements have been yielded in the diagnosis and treatment of cancer, the current first-line anti-cancer agents are insufficient owing to the emergence of multi-drug resistance and side effects. Therefore, it is urgent to develop new anti-cancer agents with high activity and low toxicity. 2-Aminothiazole is a class of important scaffold which widely distributes in many natural and synthetic compounds with many pharmacological effects including the potential anti-cancer activity. In this review, we summarized the recent progress of 2-aminothiazole as a privileged scaffold for the discovery of anti-cancer agents based on biological targets, such as tubulin protein, histone acetylase/histone deacetylase (HAT/HDAC), phosphatidylinositol 3-kinases (PI3Ks), Src/Abl kinase, BRAF kinase, epidermal growth factor receptor (EGFR) kinase and sphingosine kinase (SphK), and also investigated the structure-activity relationships (SARs) of most compounds. It is believed that this review could be helpful for medicinal chemists in the discovery of more anti-cancer agents bearing 2-aminothiazole scaffold with excellent activity and high therapeutic index.

Thiazole-containing compounds as therapeutic targets for cancer therapy

In the last few decades, considerable progress has been made in anticancer agents development, and several new anticancer agents of natural and synthetic origin have been produced. Among heterocyclic compounds, thiazole, a 5-membered unique heterocyclic motif containing sulphur and nitrogen atoms, serves as an essential core scaffold in several medicinally important compounds. Thiazole nucleus is a fundamental part of some clinically applied anticancer drugs, such as dasatinib, dabrafenib, ixabepilone, patellamide A, and epothilone. Recently, thiazole-containing compounds have been successfully developed as possible inhibitors of several biological targets, including enzyme-linked receptor(s) located on the cell membrane, (i.e., polymerase inhibitors) and the cell cycle (i.e., microtubular inhibitors). Moreover, these compounds have been proven to exhibit high effectiveness, potent anticancer activity, and less toxicity. This review presents current research on thiazoles and elucidates their biological importance in anticancer drug discovery. The findings may aid researchers in the rational design of more potent and bio-target specific anticancer drug molecules.

Design and synthesis of novel pyridazinoquinazoline derivatives as potent VEGFR-2 inhibitors: In vitro and in vivo study

Worldwide, Hepatocellular Carcinoma (HCC) endures to be a prominent cause of cancer death. Treatment of HCC follows multiple therapies which are not entirely applicable for treatment of all patients. HCC usually arises contextual to chronic liver diseases and is often discovered at later stages which makes treatment options more complex. The present study aimed at design, synthesis & evaluation of new pyridazinoquinazoline derivatives as potential nontoxic anti-hepatocellular carcinoma (HCC) agents, through inhibition of Vascular endothelial growth factor -2 (VEGFR-2). Novel Pyridazino[3, 4, 5-de]quinazoline derivatives (2-6) were designed & synthesized. Their structures were confirmed via spectral and microanalytical data. They were tested for their in vitro VEGFR-2 inhibition & anticancer activity against human liver cancer cell line (HEPG-2). Molecular docking was investigated into VEGFR-2 site. In vivo studies of VEGRF-2 inhibition and the anti-apoptotic effect of the new compounds were determined in liver of irradiated rats. Toxicity of synthesized compounds was also assessed. The results showed that compounds 3-6 have significant antitumor activity and proved to be non-toxic. The ethoxy aniline derivative 6, exhibited the highest activity both in vitro and in vivo compared to the reference drug used, sorafenib. Compound 6 could be considered a promising nontoxic anti HCC agent and this could be partially attributed to its VEGFR-2 inhibition. Future preclinical investigation would be carried out to confirm the specific and exact mechanism of action of these derivatives especially compound 6 as an effective pharmaceutical agent after full toxicological and pharmacological assessment.

FeF3-mediated tandem annulation: a highly efficient one-pot synthesis of functionalized N-methyl-3-nitro-4H-pyrimido [2, 1-b] [1, 3] benzothiazole-2-amine derivatives under neat conditions

A straight forward and highly efficient one-pot annulation of 2-aminobenzothiazole, (E)-N-methyl-1-(methylthio)-2-nitroethenamine, and aldehydes in the presence of FeF₃ is described. Diverse functionalized N-methyl-3-nitro-4H-pyrimido [2, 1-b] [1, 3] benzothiazole-2-amine derivatives were obtained with excellent yields under neat conditions. The one-pot annulation was shown to be valid for the synthesis of highly functionalized derivatives of N-methyl-3-nitro-4H-pyrimido [2, 1-b] [1, 3] benzothiazole-2-amine from readily accessible substrates. The catalyst FeF₃ can be easily recovered and reused for the next reaction without any effects on the yields of the products. This green protocol provides structurally complex, biologically important N-methyl-3-nitro-4H-pyrimido [2, 1-b] [1, 3] benzothiazole-2-amine in a one-pot operation.

Revealing quinquennial anticancer journey of morpholine: A SAR based review

Morpholine, a six-membered heterocycle containing one nitrogen and one oxygen atom, is a moiety of great significance. It forms an important intermediate in many industrial and organic syntheses. Morpholine containing drugs are of high therapeutic value. Its wide array of pharmacological activity includes anti-diabetic, anti-emetic, growth stimulant, anti-depressant, bronchodilator and anticancer. Multi-drug resistance in cancer cases have emerged in the last few years and have led to the failure of many chemotherapeutic drugs. Newer treatment methods and drugs are being developed to overcome this problem. Target based drug discovery is an effective method to develop novel anticancer drugs. To develop newer drugs, previously reported work needs to be studied. Keeping this in mind, last five year's literature on morpholine used as anticancer agents has been reviewed and summarized in the paper herein.

Design, Synthesis and Anticancer Screening of Novel Benzothiazole-Piperazine-1,2,3-Triazole Hybrids

A library of novel regioselective 1,4-di and 1,4,5-trisubstituted-1,2,3-triazole based benzothiazole-piperazine conjugates were designed and synthesized using the click synthesis approach in the presence and absence of the Cu(I) catalyst. Some of these 1,2,3-triazole hybrids possess in their structures different heterocyclic scaffold including 1,2,4-triazole, benzothiazole, isatin and/or benzimidazole. The newly designed 1,2,3-triazole hybrids were assessed for their antiproliferative inhibition potency against four selected human cancer cell lines (MCF7, T47D, HCT116 and Caco2). The majority of the synthesized compounds demonstrated moderate to potent activity against all the cancer cell lines examined. Further, we have established a structure activity relationship with respect to the in silico analysis of ADME (adsorption, distribution, metabolism and excretion) analysis and found good agreement with in vitro activity.

A Review of Environmental Occurrence, Fate, Exposure, and Toxicity of Benzothiazoles

Benzothiazole and its derivatives (BTs) are high production volume chemicals that have been used for several decades in a large number of industrial and consumer products, including vulcanization accelerators, corrosion inhibitors, fungicides, herbicides, algicides, and ultraviolet (UV) light stabilizers. Several benzothiazole derivatives are used commercially, and widespread use of these chemicals has led to ubiquitous occurrence in diverse environmental compartments. BTs have been reported to be dermal sensitizers, respiratory tract irritants, endocrine disruptors, carcinogens, and genotoxicants. This article reviews occurrence and fate of a select group of BTs in the environment, as well as human exposure and toxicity. BTs have frequently been found in various environmental matrices at concentrations ranging from sub-ng/L (surface water) to several tens of μg/g (indoor dust). The use of BTs in a number of consumer products, especially in rubber products, has resulted in widespread human exposure. BTs undergo chemical, biological, and photolytic degradation in the environment, creating several transformation products. Of these, 2-thiocyanomethylthio-benzothiazole (2-SCNMeS-BTH) has been shown to be the most toxic. Epidemiological studies have shown excess risks of cancers, including bladder cancer, lung cancer, and leukemia, among rubber factory workers, particularly those exposed to 2-mercapto-benzothiazole (2-SH-BTH). Human exposure to BTs continues to be a concern.

Enhanced cytotoxicity by a benzothiazole-containing cisplatin derivative in breast cancer cells

A synergic acting cisplatin derivative, made via conjugating CJM126 with cisplatin, was synthesized and delivered using liposomes to inhibit tumor cells.

Structure-activity relationship (SAR) study and design strategies of nitrogen-containing heterocyclic moieties for their anticancer activities

The present review article offers a detailed account of the design strategies employed for the synthesis of nitrogen-containing anticancer agents. The results of different studies describe the N-heterocyclic ring system is a core structure in many synthetic compounds exhibiting a broad range of biological activities. Benzimidazole, benzothiazole, indole, acridine, oxadiazole, imidazole, isoxazole, pyrazole, triazoles, quinolines and quinazolines including others drugs containing pyridazine, pyridine and pyrimidines are covered. The following studies of these compounds suggested that these compounds showed their antitumor activities through multiple mechanisms including inhibiting protein kinase (CDK, MK-2, PLK1, kinesin-like protein Eg5 and IKK), topoisomerase I and II, microtubule inhibition, and many others. Our concise representation exploits the design and anticancer potency of these compounds. The direct comparison of anticancer activities with the standard enables a systematic analysis of the structure-activity relationship among the series.

Synthesis and antiproliferative activity of D-ring substituted steroidal benzamidothiazoles

Using progesterone as the starting material, we synthesized a series of steroidal derivatives possessing a D-ring substituted benzamidothiazole. All of the final structures were reported and identified by NMR and HRMS spectrometry for the first time. The antiproliferative activity of the synthesized compounds against PC-3 (human prostate cancer cell line) and SKOV-3 (ovarian cancer cells) were investigated. The preliminary results showed that compounds 8b, 8d and 8g possessed moderate antiproliferative activities.

What are the challenges in 2016 regarding resistance to tyrosine kinase inhibitors in chronic myeloid leukemia and cancer?

In the past decade, the treatment of chronic myeloid leukemia (CML) has undergone a drastic evolution. The discovery and success of imatinib and second-generation tyrosine kinase inhibitors have substantially increased the outcome for CML patients. The next step in medical and scientific research is to better understand the malignancy so as to eventually find a cure to eliminate all leukemic cells from patients. One of the key issues is about the resistance of the leukemic stem cells to tyrosine kinase inhibitors. Here, we briefly describe our current studies on CML resistance, and leukemic stem cell modeling and characterization.

An Efficient Synthesis of Baricitinib

A highly efficient method for the synthesis of baricitinib was developed. The starting material tert-butyl 3-oxoazetidine-1-carboxylate was converted to intermediate 2-(1-(ethylsulfonyl)azetidin-3-ylidene)acetonitrile via the Horner–Emmons reaction, deprotection of the N-Boc-group and a final sulfonamidation reaction. Then the nucleophilic addition reaction was carried out smoothly to afford the borate intermediate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene under reflux. Finally, the desired compound baricitinib was obtained by the Suzuki coupling reaction of 4-chloro-7- H-pyrrolo[2,3- d]pyrimidine with the above borate intermediate. All compounds were characterised by IR, MS, 1H NMR and 13C NMR. The overall yield in this synthetic route was as high as 49%. Moreover, this procedure is straightforward to carry out, has low cost and is suitable for industrial production.

Design and synthesis of new potent anticancer benzothiazole amides and ureas featuring pyridylamide moiety and possessing dual B-Raf(V600E) and C-Raf kinase inhibitory activities

A new series of benzothiazole amide and urea derivatives tethered with the privileged pyridylamide moiety by ether linkage at the 6-position of benzothiazole (22 final compounds) has been designed and synthesized as potent anticancer sorafenib analogs. A selected group of twelve derivatives was appraised for its antiproliferative activity over a panel of 60 human cancer cell lines at a single dose concentration of 10 μM at National Cancer Institute (NCI, USA). Compounds 4b, 5a, 5b and 5d exhibited promising growth inhibitions and thus were further tested in advanced 5-dose testing assay to determine their GI50 values. The cellular based assay results revealed that 3,5-bis-trifluoromethylphenyl (5b) urea member is the best derivative with superior potency and efficacy compared to sorafenib as well as notable extended spectrum activity covering 57 human cancer cell lines. Kinase screening of compound 5b showed its kinase inhibitory effect against both B-Raf(V600E) and C-Raf. Moreover, the most potent derivatives in cells were investigated for their RAF inhibitory activities, and the results were rationalized with the molecular docking study. Profiling of CYP450 and hERG channel inhibitory effects for the active compounds revealed their low possibilities to exhibit undesirable drug-drug interactions and cardiac side effects.