Synthesis, anticancer activity and photostability of novel 3-ethyl-2-mercapto-thieno[2,3- d ]pyrimidin-4( 3H )-ones

Design, synthesis and cytotoxic evaluation of new thieno[2,3-d]pyrimidine analogues as VEGFR-2/AKT dual inhibitors, apoptosis and autophagy inducers

Novel thieno[2,3-d]pyrimidine analogues were designed, synthesized and evaluated for anti-proliferative activity against HepG-2, PC-3 and MCF-7 cancer cell lines. In addition, WI-38 normal cell line was used to explore the safety of all the tested compounds. Compounds 2 (IC50 = 4.29 µM HePG-2, 10.84 µM MCF-7), 6 (IC50 = 14.86 μM HePG-2, 8.04 μM PC-3 and 12.90 μM MCF-7) and 17 (IC50 = 9.98 μM HePG-2, 33.66 μM PC-3 and 14.62 μM MCF-7) were the most promising candidates on the tested cancer cells with high selective toxicity-sparing normal cells. A further mechanistic evaluation revealed promising kinase inhibitory activity, where compound 2 inhibited VEGFR-2 and AKT at IC50 = 0.161 and 1.06 μM, respectively, Furthermore, derivative 6 inhibited VEGFR-2 and AKT at IC50 = 0.487 and 0.364 μM, respectively, while compound 17 showed IC50 = 0.164 and 0.452 μM, respectively. Moreover, compounds 2, 6 resulted in G1 phase cell cycle arrest while candidate 17 arrest cell cycle at G2/M phase. Similar to the apoptosis results, compound 17 showed the highest autophagic induction among the evaluated derivatives. Finally, docking studies were conducted to assess the binding patterns of these active derivatives. The results showed that the binding patterns inside the active sites of both the VEGFR-2 and AKT-1 (allosteric pocket) crystal structures were identical to the reference ligands.

A decade's overview of 2-aminothiophenes and their fused analogs as promising anticancer agents

Over the past decades, cancer has been a challenging domain for medicinal chemists as it is an international health concern. In association, small molecules such as 2-aminothiophenes and their derivatives showed significant antitumor activity through variable modes of action. Therefore, this article aims to review the advances regarding these core scaffolds over the past 10 years, where 2-aminothiophenes and their fused analogs are classified and discussed according to their biological activity and mode of action, in the interest of boosting new design pathways for medicinal chemists to develop targeted antitumor candidates.

Design and one-pot synthesis of new substituted pyrrolo[1,2-a]thieno[3,2-e]pyrimidine as potential antitumor agents: in vitro and in vivo studies

A new efficient and versatile one-pot three-component synthesis of substituted pyrrolo[1,2-a]thieno[3,2-e]pyrimidine derivatives has been developed. It is based on a multistep cascade reaction from 2-aminothiophenes and 2-hydroxy-4-oxobut-2-enoic acids, and derivatives of cyanoacetic acid catalyzed by diisopropylethylamine. As a result, novel pyrrolo[1,2-a]thieno[3,2-e]pyrimidine derivatives (21 compounds) were synthesized in a mild reaction conditions with a high yield. The structures of the developed compounds were confirmed by NMR and elemental analysis. The influence of electron-withdrawing or electron-donor substituents on the antitumor activity of the developed compounds has been identified. In vitro screening analysis of 21 compounds revealed six lead candidates (12aa, 12dc, 12hc, 12ic, 12lb, and 12mb) that demonstrated the most significant antitumor activity against B16-F10, 4T1 and CT26 cells. Necrosis/apoptosis assay showed that apoptosis was the predominant mechanism of cell death. Molecular docking analysis revealed several potential targets for tested compounds, i.e. phosphatidylinositol 5-phosphate 4-kinase (PI5P4K2C), proto-oncogene serine/threonine-protein kinase (Pim-1), nicotinamide phosphoribosyltransferase (NAMPT) and dihydrofolate reductase (DHFR). The lead compound (12aa) can effectively induce cell apoptosis, possesses a high yield (98 %) and requires low-cost starting chemicals for its synthesis. In vivo experiments with melanoma-bearing mice confirmed that 12aa compound resulted in the significant tumor inhibition on 15 d after the therapy. In particular, tumor volume was ∼0.19 cm3 for 50 mg/kg versus ∼2.39 cm3 in case of untreated mice and tumor weight was ∼71.6 mg for 50 mg/kg versus ∼452.4 mg when considered untreated mice. Thus, our results demonstrated the high potential of the 12aa compound in the treatment of melanoma and can be recommended for further preclinical studies.

Design, synthesis, and biological evaluation of thienopyrimidine derivatives as multifunctional agents against Alzheimer's disease

A series of 12 S-substituted tetrahydrobenzothienopyrimidines were designed and synthesized based on the donepezil scaffold. All the newly synthesized compounds were evaluated for their acetylcholinesterase (AChE) inhibitory activity and the most active compounds were tested for their butyrylcholinesterase (BuChE) inhibitory activity. Moreover, all the synthesized compounds were evaluated for their inhibitory effects against Aβ aggregation and antioxidant activity using the oxygen radical absorbance capacity method. Compounds 4b, 6b, and 8b displayed the most prominent AChE inhibitory action comparable to donepezil. Compound 6b showed the greatest AChE inhibitory action (IC50  = 0.07 ± 0.003 µM) and the most potent BuChE inhibitory action (IC50  = 0.059 ± 0.004 µM). Furthermore, the three compounds exhibited significant antioxidant activity. Compounds 6b and 8b exerted more inhibitory action on Aβ aggregation than donepezil. The cytotoxic activity of compounds 4b, 6b, and 8b against the WI-38 cell line in comparison with donepezil was examined using 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay. The results revealed that compounds 6b and 8b were less cytotixic than donepezil, while compound 4b showed nonsignificant cytotoxicity compared to donepezil. For more insights about the binding patterns of the most promising compounds (4b, 6b, and 8b) with the AChE at molecular levels; molecular docking and molecular dynamics simulations were performed. The density functional theory calculations and absorption, distribution, metabolism, excretion and toxicity properties were described as well. The results highlighted compound 6b, which incorporates a phenylpiperazine moiety coupled to a thienopyrimidone scaffold via two-atom spacer, to be a promising multifunctional therapeutic agent for the treatment of Alzheimer's disease. It is a potent dual AChE and BuChE inhibitor. Furthermore, it had stronger Aβ aggregation inhibitory action than donepezil. Additionally, compound 6b exerted significant antioxidant activity.

Design, synthesis, anti-proliferative evaluation, docking, and MD simulation studies of new thieno[2,3-d]pyrimidines targeting VEGFR-2

In this work, new thieno[2,3-d]pyrimidine-derived compounds possessing potential anticancer activities were designed and synthesized to target VEGFR-2. The thieno[2,3-d]pyrimidine derivatives were tested in vitro for their abilities to inhibit VEGFR-2 and to prevent cancer cell growth in two types of cancer cells, MCF-7 and HepG2. Compound 18 exhibited the strongest anti-VEGFR-2 potential with an IC50 value of 0.084 μM. Additionally, it displayed excellent proliferative effects against MCF-7 and HepG2 cancer cell lines, with IC50 values of 10.17 μM and 24.47 μM, respectively. Further studies revealed that compound 18 induced cell cycle arrest in G2/M phase and promoted apoptosis in MCF-7 cancer cells. Apoptosis was stimulated by compound 18 by increasing BAX (3.6-fold) and decreasing Bcl-2 (3.1-fold). Additionally, compound 18 significantly raised the levels of caspase-8 (2.6-fold) and caspase-9 (5.4-fold). Computational techniques were also used to investigate the VEGFR-2-18 complex at a molecular level. Molecular docking and molecular dynamics simulations were performed to assess the structural and energetic features of the complex. The protein-ligand interaction profiler analysis identified the 3D interactions and binding conformation of the VEGFR-2-18 complex. Essential dynamics (ED) study utilizing principal component analysis (PCA) described the protein dynamics of the VEGFR-2-18 complex at various spatial scales. Bi-dimensional projection analysis confirmed the proper binding of the VEGFR-2-18 complex. In addition, the DFT studies provided insights into the structural and electronic properties of compound 18. Finally, computational ADMET and toxicity studies were conducted to evaluate the potential of the thieno[2,3-d]pyrimidine derivatives for drug development. The results of the study suggested that compound 18 could be a promising anticancer agent that may provide effective treatment options for cancer patients. Furthermore, the computational techniques used in this research provided valuable insights into the molecular interactions of the VEGFR-2-18 complex, which may guide future drug design efforts. Overall, this study highlights the potential of thieno[2,3-d]pyrimidine derivatives as a new class of anticancer agents and provides a foundation for further research in this area.

Synthesis of thieno[3,2-e]pyrrolo[1,2-a]pyrimidine derivatives and their precursors containing 2-aminothiophenes fragments as anticancer agents for therapy of pulmonary metastatic melanoma

The design and synthesis of new promising compounds based on thienopyrimidine scaffold containing 2-aminothiophene fragments with good safety and favorable drug-like properties are highly relevant for chemotherapy. In this study, a series of 14 variants of thieno[3,2-e]pyrrolo[1,2-a]pyrimidine derivatives (11aa-oa) and their precursors (31 compounds) containing 2-aminothiophenes fragments (9aa-mb, 10aa-oa) were synthesized and screened for their cytotoxicity against B16-F10 melanoma cells. The selectivity of the developed compounds was assessed by determining the cytotoxicity using normal mouse embryonic fibroblasts (MEF NF2 cells). The lead compounds 9cb, 10ic and 11jc with the most significant antitumor activity and minimum cytotoxicity on normal non-cancerous cells were chosen for further in vivo experiments. Additional in vitro experiments with compounds 9cb, 10ic and 11jc showed that apoptosis was the predominant mechanism of death in B16-F10 melanoma cells. With support from in vivo studies, compounds 9cb, 10ic and 11jc demonstrated the biosafety to healthy mice and significant inhibition of the metastatic nodules in pulmonary metastatic melanoma mouse model. Histological analysis detected no abnormal changes in the main organs (the liver, spleen, kidneys, and heart) after the therapy. Thus, the developed compounds 9cb, 10ic and 11jc demonstrate high efficiency in the treatment of pulmonary metastatic melanoma and can be recommended for further preclinical investigation of the melanoma treatment.

Recent updates on thienopyrimidine derivatives as anticancer agents

Thienopyrimidine derivatives hold a unique place between fused pyrimidine compounds. They are important and widely represented in medicinal chemistry as they are structural analogs of purines. Thienopyrimidine derivatives have various biological activities. The current review discusses different synthetic methods for the preparation of heterocyclic thienopyrimidine derivatives. It also highlights the most recent research on the anticancer effects of thienopyrimidines through the inhibition of various enzymes and pathways, which was published within the last 9 years.

Graphical Abstract

Novel Thioethers of Dihydroartemisinin Exhibiting Their Biological Activities

Eleven conjugates between dihydroartemisinin (DHA) with thiols containing both ether and thioether bonds were designed, synthesized by a two-step procedure including etherification and S-alkylation. Analysis of the NMR spectral data indicated that the dimer of DHA with thiols 6-mercaptopurine and 2-mercaptoimidazole was produced with yields of 31% and 62%, respectively. Furthermore, the tautomerization of thiol 5-methoxy-2-mercaptobenzimidazole led to the formation of a mixture of two isomers in which they might be interchangeable through a dynamic tautomeric equilibrium in the solution. Screening in vitro biological activities revealed that most of the synthesized conjugates showed good cytotoxic and anti-inflammatory activity, while three of them displayed α-glucosidase inhibitory activity. Notably, two conjugates 5d and 5e of DHA with thiols 2-mercaptopyrimidine and 2-mercaptobenzothiazole had an effect in all tested activities in which conjugate 5e is the most potent.

Thioethers: An Overview

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Spreading rapidly in recent years, cancer has become one of the causes of the highest mor-tality rates after cardiovascular diseases. The reason for cancer development is still not clearly under-stood despite enormous research activities in this area. Scientists are now working on the biology of cancer, especially on the root cause of cancer development. The aim is to treat the cancer disease and thus cure the patients. The continuing efforts for the development of novel molecules as potential anti-cancer agents are essential for this purpose. The main aim of this review was to present a survey on the medicinal chemistry of thioethers and provide practical data on their cytotoxicities against various cancer cell lines. The research articles published between 2001-2020 were consulted to pre-pare this review article; however, patent literature has not been included. The thioether-containing heterocyclic compounds may emerge as a new class of potent and effective anti-cancer agents in the future.

Design and Synthesis of New Thiophene/Thieno[2,3-d]pyrimidines along with Their Cytotoxic Biological Evaluation as Tyrosine Kinase Inhibitors in Addition to Their Apoptotic and Autophagic Induction

This work describes the synthesis and anticancer activity against kinase enzymes of newly designed thiophene and thieno[2,3-d]pyrimidine derivatives, along with their potential to activate autophagic and apoptotic cell death in cancer cells. The designed compounds were scanned for their affinity for kinases. The results were promising with affinity ranges from 46.7% to 13.3%. Molecular docking studies were performed, and the compounds were then screened for their antiproliferative effects. Interestingly, compounds 8 and 5 resulted in higher cytotoxic effects than the reference standard against MCF-7 and HepG-2. The compounds were evaluated for their induction of apoptosis and/or necrosis on HT-29 and HepG-2. Three compounds induced significant early apoptosis compared to untreated control HT-29 cells, and four derivatives were more significant compared to untreated HepG-2 cells. We further investigated the effect of four compounds on the autophagy process within HT-29, HepG-2, and MCF-7 cells with flow cytometry. Similar to the apoptosis results, compound 5 showed the highest autophagic induction among all compounds. The potential inhibitory activity of the synthesized compounds on kinases was assessed. Screened compounds showed inhibition activity ranging from 41.4% to 83.5%. Compounds recorded significant inhibition were further investigated for their specific FLT3 kinase inhibitory activity. Noticeably, Compound 5 exhibited the highest inhibitory activity against FLT3.

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.

New C2- and N3-Modified Thieno[2,3-d]Pyrimidine Conjugates with Cytotoxicity in the Nanomolar Range

AIMS

The aim of the current study was to develop and explore a series of new cytotoxic agents based on the conjugation between the thieno[2,3-d]pyrimidine moiety and a second pharmacophore at the C2 or N3 position.

BACKGROUND

As the thieno[2,3-d]pyrimidine core is a bioisostere of the 4-anilinoquinazoline, various new thienopyrimidine derivatives were synthesized by modifying the structure of the clinically used anticancer quinazoline EGFR inhibitors of the first generation - gefitinib, and second generation - dacomitinib and canertinib. It was reported that some thieno[2,3-d]pyrimidine derivatives showed improved EGFR inhibitory activity. On the other hand, the benzimidazole heterocycle is present as a pharmacophore unit in the structure of many clinically used chemotherapeutic agents. Some 2-aminobenzimidazole derivatives, possessing anticancer activity, demonstrated EGFR inhibition and the benzimidazole derivative EGF816 is currently in the second phase of clinical trials.

OBJECTIVE

The objectives of the study were design of a novel series thieno[2,3-d]pyrimidines, synthesis of the compounds and investigation of their effects towards human cancer HT-29, MDA-MB-231, HeLa, HepG2 and to normal human Lep3 cell lines. (American Type Culture Collection, ATCC, Rockville, MD, USA) Methods: The synthetic protocol implemented cyclocondensation of 2-amino-thiophenes and nitriles in inert medium, aza-Michael addition to benzimidazole derivatives and nucleophylic substitution at the N3 place. MTS test was used in order to establish the cytotoxicity of the tested compounds. SAR analysis and in silico assessment of the inhibitory potential towards human oncogenic V^599EB-Raf were performed using Molinspiration tool and Molecular Operating environment software.

RESULTS

The MTS test data showed that almost all studied thieno[2,3-d]pyirimidines (9-13, 21-22 and 25) manifest high inhibiting effect on the cell proliferation at nanomolar concentrations, whereat compounds 9 (IC₅₀ = 130 nM) and 10 (IC₅₀ = 261 nM) containing amino acid moiety, and 21 (IC₅₀ = 108 nM) possesing two thienopyrimidine moieties attached to a 1,3-disubstituted benzimidazole linker, revealed many times lower toxicity against Lep3 cells compared to the cancer cells. Thienopyrimidines 11-13 possessed high selectivity against HeLa cells. Compound 13 showed high inhibitory activity against MDA-MB-231 and HepG2, with IC50 1.44 nM and 1.11 nM respectively. To outline the possible biological target of the studied coumpounds, their potential to interact with human oncogenic V^599EB-Raf was explored by a docking study. As a result, it was suggested that the benzimidazolyl and glycyl fragments could enhance the binding ability of the new compounds by increasing the number of hydrogen bond acceptors and by stabilizing the inactive form of the enzyme.

CONCLUSION

The thienopyrimidines tested in vitro towards human cancer HT-29, MDA-MB-231, HeLa, HepG2 and normal human Lep3 cell lines demonstrated cytotoxicity in nanomolar range. It was established that compounds 9, 10 and 21 showed many times lower toxicity against normal Lep3 cells that can provide a high selectivity towards all four cancer cell lines at small concentrations. Based on the analysis of the structure-activity relationship, the observed trends in the cytotoxicity could be related to the lipophilicity and the topological polar surface area of the tested compounds. The docking study on the potential of the new thieno[2,3-d]pyrimidine-4-ones to interact with mutant V^599EB-Raf showed that the compounds might be able to stabilize the enzyme in its inactive form.

Pyrimidine: a review on anticancer activity with key emphasis on SAR

Background

Cancer is a global health challenge, it impacts the quality of life and its treatment is associated with several side effects. Resistance of the cancer cells to the existing drugs has led to search for novel anticancer agents. Pyrimidine, a privileged scaffold, is part of living organisms and plays vital role in various biological procedures as well as in cancer pathogenesis. Due to resemblance in structure with the nucleotide base pair of DNA and RNA, it is recognized as valuable compound in the treatment of cancer.

Main text

Many novel pyrimidine derivatives have been designed and developed for their anticancer activity in the last few years. The present review aims to focus on the structure activity relationship (SAR) of pyrimidine derivatives as anticancer agent from the last decade.

Conclusion

This review intends to assist in the development of more potent and efficacious anticancer drugs with pyrimidine scaffold.

Graphical abstract

Thieno[2,3-d]pyrimidin-4(3H)-one Derivatives of Benzimidazole as Potential Anti- Breast Cancer (MDA-MB-231, MCF-7) Agents

AIMS

The purpose of this study was the synthesis of some new thienopyrimidine derivatives of 1,3-disubstituted benzimidazoles and the evaluation of their cytotoxicity against MDA-MB-231, MCF-7, and 3T3 cells lines.

BACKGROUND

An overexpression or mutational activation of TK receptors EGFR and HER2/neu is characteristic of tumors. It has been found that some thieno[2,3-d]pyrimidines exhibited better inhibitory activity against Epidermal Growth Factor Receptor (EGFR/ErbB-2) tyrosine kinase in comparison to aminoquinazolines. Breast cancer activity towards MDA-MB-231 and MCF-7 cell lines by inhibiting EGFR was revealed by a novel 2-arylbenzimidazole. This motivated the synthesis of new thienopyrimidines possessing benzimidazole fragments in order to evaluate their cytotoxicity to the above-mentioned cell lines.

OBJECTIVE

The objectives of the study were to design and synthesize a novel series of thieno[2,3-d]pyrimidines bearing biologically active moieties, such as 1,3-disubstituted-benzimidazole heterocycle, structurally similar to diaryl ureas in order to evaluate their cytotoxicity against MDA-MB-231, and MCF-7 breast cancer cell lines.

METHODS

N,N-disubstituted benzimidazole-2-one carbonitriles were synthesized by Aza-Michael addition and used as precursors to generate some of the new thieno[2,3-d]pyrimidines in acidic medium The interaction of chloroethyl-2-thienopyrimidines, 2-amino-benzimidazole and benzimidazol-2-one nitriles under solid-liquid transfer catalysis conditions led to new thienopyrimidines. MTT assay for cell survival was performed in order to evaluate the cytotoxicity of the tested compounds. A fluorescence study was conducted to elucidate some aspects of the mechanism of action.

RESULTS

The effects of nine synthesized compounds were investigated towards MDA-MB-231, MCF-7 and 3T3 cell lines. Thieno[2,3-d]pyirimidine-4-one 16 (IC₅₀ - 0.058μM) and 21 (IC₅₀ - 0.029μM) possess high cytotoxicity against MDA-MB-231 cells after 24h. The most cytotoxic compounds against breast cancer MCF-7 cells was compound 21 (IC₅₀ - 0.074μM), revealing lower cytotoxicity against mouse fibroblast 3T3 cells with IC₅₀ - 0.20μM. SAR analysis was performed. Fluorescence study of the treatment of MDA-MB cells with compound 21 was carried out in order to clarify some aspects of the mechanism of action.

CONCLUSION

The relationship between cytotoxicity of compounds 14 and 20 against MCF-7 and 3T3 cells can suggest a similar mechanism of action. The antitumor potential of the tested compounds proves the necessity for further investigation to estimate the exact inhibition pathway in the cellular processes. The fluorescence study of the treatment of MDA-MB cells with compound 21 showed a rapid process of apoptosis.

A Review on Anticancer Activities of Thiophene and Its Analogs

Cancer is the world's second-largest cause of mortality and one of the biggest global health concerns. The prevalence and mortality rates of cancer remain high despite significant progress in cancer therapy. The search for more effective, as well as less toxic treatment methods for cancer, is at the focus of current studies. Thiophene and its derivatives have surged as an influential scaffold, which, because of their appreciable diversity in biological activities, has drawn the concerned interest of the researchers in the field of medicinal chemistry. By the affluent introduction of its derivatives, which have antioxidant, anti-inflammatory, antimicrobial, and anticancer activities, the adaptability of the thiophene moiety has been displayed. The nature and positioning of the substitutions significantly impacted thiophene moiety activity. This decent array in the living response account about this moiety has picked plentiful researcher's consideration to inquire about it to its peculiar potential across certain activities. In the field of cancer therapy against different cancer cells, the structure-activity relationship for each of the derivatives showed an excellent understanding of thiophene moiety. Information from the various articles revealed the key role of thiophene moiety and its derivatives to develop the vital lead compound. The essential anticancer mechanisms identified include inhibition of the topoisomerase, inhibition of tyrosine kinase, tubulin interaction and apoptosis induction through the activation of reactive oxygen species. This review is an endeavor to promote the anticancer potential of the derivatives, whether having thiophene or condensed thiophene as a core moiety or as a substituent that can lead in the future to synthesize varieties of chemotherapeutic entities in the field of cancer treatment.

Discovery of New Apoptosis-Inducing Agents for Breast Cancer Based on Ethyl 2-Amino-4,5,6,7-Tetra Hydrobenzo[b]Thiophene-3-Carboxylate: Synthesis, In Vitro, and In Vivo Activity Evaluation

A multicomponent synthesis was empolyed for the synthesis of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate 1. An interesting cyclization was obtained when the amino-ester 1 reacted with ethyl isothiocyanate to give the benzo[4,5]thieno[2,3-d][1,3]thiazin-4-one 3. Acylation of the amino-ester 1 with chloroacetyl chloride in DCM and Et₃N afforded the acylated ester 4. The amino-ester 1 was cyclized to benzo[4,5]thieno[2,3-d]pyrimidin-4(3H)-one 8, which was reacted with some alkylating agents leading to alkylation at nitrogen 9–13. Hydrazide 14 was utilized as a synthon for the synthesis of the derivatives 15–19. Chloro-thieno[2,3-d]pyrimidine 20 was synthesized and reacted with the hydrazine hydrate to afford the hydrazino derivative 21, which was used as a scaffold for getting the derivatives 22–28. Nucleophilic substitution reactions were used for getting the compounds 29–35 from chloro-thieno[2,3-d]pyrimidine 20. In the way of anticancer therapeutics development, the requisite compounds were assessed for their cytotoxicity in vitro against MCF-7 and HepG-2 cancer cell lines. Twelve compounds showed an interesting antiproliferative potential with IC₅₀ from 23.2 to 95.9 µM. The flow cytometric analysis results showed that hit 4 induces the apoptosis in MCF-7 cells with a significant 26.86% reduction in cell viability. The in vivo study revealed a significant decrease in the solid tumor mass (26.6%) upon treatment with compound 4. Moreover, in silico study as an agonist for inhibitors of JAK2 and prediction study determined their binding energies and predicted their physicochemical properties and drug-likeness scores.

Phenothiazine and amide-ornamented novel nitrogen heterocyclic hybrids: synthesis, biological and molecular docking studies

The synthesis of phenothiazine and amide-ornamented nitrogen heterocycles (25–34) has been accomplished utilizing a multi-step synthetic protocol and the structures have been established based on physical and spectral techniques.

Thieno[2,3-d]pyrimidine as a promising scaffold in medicinal chemistry: Recent advances

Thienopyrimidine scaffold is a fused heterocyclic ring system that structurally can be considered as adenine, the purine base that is found in both DNA and RNA-bioisosteres. Thienopyrimidines exist in three distinct isomeric forms. The current review discusses thieno[2,3-d]pyrimidine as a one of the opulent heterocycles in drug discovery. Its broad range of medical applications such as anticancer, anti-inflammatory, anti-microbial, and CNS protective agents has inspired us to study its structure-activity relationship (SAR), along with its relevant synthetic strategies. The present review briefly summarizes synthetic approaches for the preparation of thieno[2,3-d]pyrimidine derivatives. In addition, the promising biological activities of this scaffold are also illustrated with explanatory diagrams for their SAR studies.

Recent advances of RAF (rapidly accelerated fibrosarcoma) inhibitors as anti-cancer agents

Frequent oncogenic mutations have been identified in MAPK (mitogen-activated protein kinase) signaling pathway components. As a result, MAPK pathway is associated with human cancer initiation, in particular RAF (rapidly accelerated fibrosarcoma) component. The mutation in RAF component leads to auto-activation of MAPK signaling pathway, stimulating the uncontrolled cell growth and proliferation. In last few years, diverse chemical scaffolds have been identified as RAF inhibitors. Most of these scaffolds show potent anti-cancer activity. The present review highlights the recent investigations of RAF inhibitors during the last five years.

Thienopyrimidine derivatives exert their anticancer efficacy via apoptosis induction, oxidative stress and mitotic catastrophe

In this study, a series of 13 structural variants of thieno[2,3d]pyrimidine derivatives (6a-6m) were synthesized and screened for cytotoxicity in a panel of colorectal, ovarian, and brain cancer cell lines. The selectivity of the compounds was assessed by determining the cytotoxicity in normal epithelial cell line (CHO). The most potent compound, 6j, was efficacious (with IC₅₀ range of 0.6-1.2 μM) in colon (HCT116 and HCT15), brain (LN-229 and GBM-10) and ovarian (A2780 and OV2008) cancer cell lines. In contrast, in the normal cell line (CHO), the IC₅₀ values for 6j were 14 ± 1.3 μM. Compound 6j significantly inhibited the clonogenic potential of HCT116, OV2008 and A2780 cell lines in concentration - dependent (0.5-4 μM) manner. Also, 6j induced 1) formation of reactive oxygen species; 2) apoptosis and 3) mitotic catastrophe in HCT116 and OV2008 cells (IC₅₀ = 0.5-2 μM). Furthermore, apoptosis was the predominant mechanism of death in A2780 cells. The cytotoxicity of 6j in wild type HCT116 cells was similar to that in HCT116 cells lacking the apoptotic genes for Bax, Bak, or Bak and Bax, indicating that 6j induces mitotic catastrophe as alternative mechanism of death when when certain apoptotic proteins are absent. In summary, this study has identified a lead molecule, 6j, that selectively induces oxidative stress, apoptosis and mitotic catastrophe in specific cancer (colon and ovarian) cell lines.

Rational design, synthesis, and biological evaluation of Pan-Raf inhibitors to overcome resistance

We describe the design and characterization of a series of pyrimidine scaffolds as Pan-Raf inhibitors, which may overcome the resistance associated with current BRaf^V600E inhibitors.