Facile synthesis and antitumor activity of novel 2-trifluoromethylthieno[2,3-d]pyrimidine derivatives

2-Alkyl-Substituted-4-Amino-Thieno[2,3-d]Pyrimidines: Anti-Proliferative Properties to In Vitro Breast Cancer Models

Thienopyrimidines are structural analogs of quinazolines, and the creation of new 2-alkyl derivatives of ethyl 4-aminothienopyrimidine-6-carboxylates for the study of their anti-proliferative properties is of great pharmacological interest. Some 2-alkyl-4-amino-thieno[2,3-d]pyrimidines 2-5 were synthesized, and their cyto- and phototoxicity against BALB 3T3 cells were established by an in vitro 3T3 NRU test. The obtained results indicate that the tested compounds are not cytotoxic or phototoxic, and that they are appropriate to be studied for their anti-proliferative and anti-tumor properties. The anti-proliferative potential of the compounds was investigated on MCF-7 and MDA-MB-231 cancer cells, as well as a MCF-10A cell line (normal human mammary epithelial cells). The most toxic to MCF-7 was thienopyrimidine 3 with IC50 13.42 μg/mL (IC50 0.045 μM), followed by compound 4 (IC50 28.89 μg/mL or IC50 0.11 μM). The thienopyrimidine 4 revealed higher selectivity to MCF-7 and lower activity (IC50 367 μg/mL i.e., 1.4 μM) than compound 3 with MCF-10A cells. With respect to MDA-MB-231 cells, ester 2 manifested the highest effect with IC50 52.56 μg/mL (IC50 0.16 μM), and 2-ethyl derivative 4 revealed IC50 62.86 μg/mL (IC50 0.24 μM). It was estimated that the effect of the substances on the cell cycle progression was due to cell cycle arrest in the G2 stage for MDA-MB-231, while arrest in G1 was detected for the estrogen (ER)-positive MCF-7 cell line. The tested compound's effects on the change of the zeta potential in the tumorigenic cells utilized in this study were determined. The calculation which we performed of the physicochemical properties and pharmacokinetic parameters influencing the biological activity suggested high intestinal absorption, as well as drug-likeness.

Study of the reactivity of aminocyanopyrazoles and evaluation of the mitochondrial reductive function of some products

This research investigated the general high-throughput synthetic protocol for the accelerated synthesis of functionalized trifluoromethylpyrazolopyrimidines 3 and N-(5-cyano-3-methyl-1-phenyl-1H-pyrazol-4-yl) benzamide 4 from aminocyanopyrazole 1 precursors. The action of chlorosulfonyl isocyanate (CSI) with aminopyrazolo[3,4-d]pyrimidines 2 was found to produce triazolopyrimidinones 5 . The MTT test that quantifies mitochondrial reductive function demonstrated that in both cell lines tested (PE/CA-PJ41 and HePG2 cells), the benzamide compounds 4 are moderately toxic with PE/CA-PJ41 cells and more sensitive than HePG2 cells.

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.

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.

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.