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.

Discovery of new VEGFR-2 inhibitors and apoptosis inducer-based thieno[2,3-d]pyrimidine

Background: VEGFR-2 is a key regulator of cancer cell proliferation, migration and angiogenesis. Aim: Development of thieno[2,3-d]pyrimidine derivatives as potential anti-cancer agents targeting VEGFR-2. Methods: Seven in vitro and nine in silico studies were conducted. Results: Compound 10d demonstrated strong anticancer potential, boosting apoptosis based on VEGFR-2 inhibition. It arrested the S phase of the cell cycle and upregulated the apoptotic factors. Docking and molecular dynamics simulation studies confirm the stability of the VEGFR-2-10d complex and suggest that these compounds have good binding affinities to VEGFR-2. In addition, the drug-likeness was confirmed. Conclusion: Thieno[2,3-d]pyrimidines, particularly compound 10d, has good anticancer effects and may contribute to the development of new anticancer therapies.

A novel thieno[2,3-d]pyrimidine derivative inhibiting vascular endothelial growth factor receptor-2: A story of computer-aided drug discovery

Following the pharmacophoric features of vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitors, a novel thieno[2,3-d]pyrimidine derivative has been designed and its activity against VEGFR-2 has been demonstrated by molecular docking studies that showed an accurate binding mode and an excellent binding energy. Furthermore, the recorded binding was confirmed by a series of molecular dynamics simulation studies, which also revealed precise energetic, conformational, and dynamic changes. Additionally, molecular mechanics with generalized Born and surface area solvation and polymer-induced liquid precursors studies were conducted and verified the results of the MD simulations. Next, in silico absorption, distribution, metabolism, excretion, and toxicity studies have also been conducted to examine the general drug-like nature of the designed candidate. According to the previous results, the thieno[2,3-d]pyrimidine derivative was synthesized. Fascinatingly, it inhibited VEGFR-2 (IC50  = 68.13 nM) and demonstrated strong inhibitory activity toward human liver (HepG2), and prostate (PC3) cell lines with IC50 values of 6.60 and 11.25 µM, respectively. As well, it was safe and showed a high selectivity index against normal cell lines (WI-38). Finally, the thieno[2,3-d]pyrimidine derivative arrested the growth of the HepG2 cells at the G2/M phase inducing both early and late apoptosis. These results were further confirmed through the ability of the thieno[2,3-d]pyrimidine derivative to induce significant changes in the apoptotic genes levels of caspase-3, caspase-9, Bcl-2 associated X-protein, and B-cell lymphoma 2.

Design, synthesis, anticancer evaluation, and in silico studies of some thieno[2,3-d]pyrimidine derivatives as EGFR inhibitors

New series of 20 thieno[2,3-d]pyrimidine derivatives have been synthesized. The National Cancer Institute evaluated all the newly synthesized compounds for their antiproliferative activity against a panel of 60 cancer cell lines. Compound 7b exhibited a remarkable antineoplastic activity at 10 µM dose and was therefore tested at five dose concentrations. The significant and broad-spectrum antineoplastic action of compound 7b was observed against 37 of the tested cancer cell lines with a dose that inhibits 50% of the growth compared to control values in the micromolar range of 1.95-9.6 µM. The dose which inhibits the growth completely in the cytostatic range of 3.99-100 µM was also observed. Compound 7b effectively inhibited epidermal growth factor receptor (EGFR) with 50% inhibition concentration value (IC50 ) = 0.096 ± 0.004 compared to erlotinib with IC50  = 0.037 ± 0.002. Moreover, compound 7b revealed a powerful downregulation effect on total EGFR concentration and its phosphorylation. In addition, compound 7b inhibited phosphatidylinositol 3-kinase, protein kinase B, and the mammalian target of rapamycin pathway phosphorylation. Furthermore, compound 7b raised total apoptosis by 21.93-fold in the ovarian cancer cell line (OVCAR-4) and caused an arrest in the cell cycle in the G1/S phase. It also raised the level of caspase-3 by 4.72-fold. Furthermore, to determine the binding manner of the most effective derivatives and validate their capacity to comply with the pharmacophoric properties necessary for EGFR inhibition, they were docked into the active site of the EGFR.

Discovery of new thieno[2,3-d]pyrimidines as EGFR tyrosine kinase inhibitors for cancer treatment

Background: EGFR has been considered a vital molecular target in cancer management. Aim: The discovery of new thieno[2,3-d]pyrimidine derivatives as EGFR tyrosine kinase inhibitors. Methods: Nine derivatives were designed, synthesized and subjected to in vitro and in silico studies. Results: Compound 7a significantly inhibited the growth of HepG2 and PC3 cells for both EGFR wild-type and EGFRT790M. Compound 7a caused a significant apoptotic effect, arresting HepG2 cells' growth in the S and G2/M phases. Docking and molecular dynamics simulation studies confirmed the correct and stable binding modes of the synthesized compounds against the active sites. Conclusion: Compound 7a is a promising dual EGFR inhibitor for cancer treatment.

Thieno[2,3-d]pyrimidine-Core Compounds Show Activity Against Clinically Relevant Gram-Positive Bacteria

Thieno[2,3- d ]pyrimidines represent a novel antibacterial prodrug scaffold, previously identified through a screening campaign against Mycobacterium tuberculosis in which the formation of highly antimycobacterial metabolites catalyzed by the nitroreductase Mrx2 is suggested to be the relevant killing mechanism. As analogical activation pathways may also be employed in other prokaryotes, in this work we explored general antibacterial effects of this compound class. Through exploration of the chemical space by different synthetic strategies, 51 novel derivatives were generated, biologically evaluated and thus enabled initial conclusions about structure-activity-relationships. Remarkably, anti-Gram-positive activity can be well modulated, particularly towards Staphylococci (MRSA) and even slightly against some Gram-negative strains. The two most promising hit compounds showed good pharmacokinetic properties in vitro as well as acceptable toxicity in HeLa cells qualifying them as starting points for lead generation campaigns.

Novel 2,4-disubstituted quinazoline analogs as antibacterial agents with improved cytotoxicity profile: Modification of the benzenoid part

Bacterial resistance to currently used antibiotics demands the development of novel antibacterial agents with good safety margins and sufficient efficacy against multi-drug resistant isolates. We have previously described the synthesis of N-butyl-2-(butylthio)quinazolin-4-amine (I) as an optimized hit with broad-spectrum antibacterial activity and low cytotoxicity. In addition, we have identified a potential growing vector for this series of compounds. Herein, we describe further hit optimization which includes systematic diversifications of both the benzenoid part and the substituents at position 6 and 7 of compound I. Growing of the molecule beside the core modifications yielded several compounds with remarkable anti(myco)bacterial activity against a panel of pathogenic bacteria, including drug-resistant strains. Compound 12 showed a 2-4 fold improvement in activity than I against S. aureus Newman, S. pneumoniae DSM-20566 and E. faecalis DSM-20478. The compounds also showed a good safety profile towards human HepG2 cells.

Synthesis and Evaluation of Biological and Antitumor Activities of Tetrahydrobenzothieno[2,3-d]Pyrimidine Derivatives as Novel Inhibitors of FGFR1

A series of tetrahydrobenzothieno[2,3-d]pyrimidine derivatives were designed, synthesized, and evaluated as inhibitors of FGFR1. These analogs were synthesized via Gewald's reaction under mild conditions. The structures of the synthesized compounds were characterized by spectroscopic data (IR, (1) H NMR and MS). Their antitumor activities were evaluated against H460, A549 and U251 cell lines in vitro. Results revealed that the tested compounds showed moderate antitumor activities. Structure-activity relationship analyses indicated that compounds with an aromatic ring substituted in the C-2 position or with larger molecules such as 3g, 4c, and 7 were more effective than others. The compound, 3g (78.8% FGFR1 inhibition at 10 μm), was identified to have the most potent antitumor activities, with IC50 values of 7.7, 18.9, and 13.3 μm against the H460, A549, and U251 cell lines, respectively. Together, the results suggested that tetrahydrobenzothieno[2,3-d]pyrimidine derivatives may serve as a potential agent for the treatment of FGFR1-mediated cancers.

C-C (alkynylation) vs C-O (ether) bond formation under Pd/C-Cu catalysis: synthesis and pharmacological evaluation of 4-alkynylthieno[2,3-d]pyrimidines

The Pd/C-CuI-PPh(3) catalytic system facilitated C-C bond formation between 4-chlorothieno[2,3-d]pyrimidines and terminal alkynes in methanol with high selectivity without generating any significant side products arising from C-O bond formation between the chloro compounds and methanol. A variety of novel 4-alkynylthieno[2,3- d]pyrimidines were prepared via alkynylation of 4-chlorothieno[2,3-d]pyrimidines in good to excellent yields. Some of the compounds synthesized were tested for cytotoxic activity in vitro.