Design, synthesis of new pyrimidine derivatives as anticancer and antimicrobial agents

Design, synthesis, molecular modelling and biological evaluation of novel 6-amino-5-cyano-2-thiopyrimidine derivatives as potent anticancer agents against leukemia and apoptotic inducers

Herein, a novel series of 6-amino-5-cyano-2-thiopyrimidines and condensed pyrimidines analogues were prepared. All the synthesized compounds (1a-c, 2a-c, 3a-c, 4a-r and 5a-c) were evaluated for in vitro anticancer activity by the National Cancer Institute (NCI; MD, USA) against 60 cell lines. Compound 1c showed promising anticancer activity and was selected for the five-dose testing. Results demonstrated that compound 1c possessed broad spectrum anti-cancer activity against the nine cancerous subpanels tested with selectivity ratio ranging from 0.7 to 39 at the GI50 level with high selectivity towards leukaemia. Mechanistic studies showed that Compound 1c showed comparable activity to Duvelisib against PI3Kδ (IC50 = 0.0034 and 0.0025 μM, respectively) and arrested cell cycle at the S phase and displayed significant increase in the early and late apoptosis in HL60 and leukaemia SR cells. The necrosis percentage showed a significant increase from 1.13% to 3.41% in compound 1c treated HL60 cells as well as from 1.51% to 4.72% in compound 1c treated leukaemia SR cells. Also, compound 1c triggered apoptosis by activating caspase 3, Bax, P53 and suppressing Bcl2. Moreover, 1c revealed a good safety profile against human normal lung fibroblast cell line (WI-38 cells). Molecular analysis of Duvelisib and compound 1c in PI3K was performed. Finally, these results suggest that 2-thiopyrimidine derivative 1c might serve as a model for designing novel anticancer drugs in the future.

Synthesis, Anti-Cancer Activity, Cell Cycle Arrest, Apoptosis Induction, and Docking Study of Fused Benzo[h]chromeno[2,3-d]pyrimidine on Human Breast Cancer Cell Line MCF-7

Breast cancer is the predominant form of cancer among women and ranks as the second most prevalent cancer globally, affecting both developed and less developed countries. Presently, accessible cancer treatment methods either employ recently created, secure, and efficient chemotherapeutic medications or directly target innovative pathways that cause apoptosis. One of the indirect strategies for treating this fatal illness has mostly depended on its essential role in cell cycle arrest and apoptosis induction, as well as the antagonistic interaction between the Bcl-2 and Mcl-1 proteins, in order to avert major health repercussions. We reported that newly synthesized fused chromenopyrimidines (3a and 4a) showed potential cell cycle arrest and dual Bcl-2 and Mcl-1 inhibitory characteristics. Bcl-2 and Mcl-1 were the targets of a molecular docking procedure. The previous docking results are in line with the biological data and suggest that 3a may have promising anti-cancer activity.

Anticancer potential and structure activity studies of purine and pyrimidine derivatives: an updated review

Cancer is the world's leading cause of death impacting millions of lives globally. The increasing research over the past several decades has focused on the development of new anticancer drugs, but still cancer continues to be a global health challenge. Thus, several new alternative therapeutic strategies have been tried for the drug design and discovery. Purine and pyrimidine heterocyclic compounds have received attention recently due to their potential in targeting various cancers. It is evident from the recently published data over the last decade that incorporation of the purine and pyrimidine rings in the synthesized derivatives resulted in the development of potent anticancer molecules. This review presents synthetic strategies encompassing several examples of recently developed purine and pyrimidine-containing compounds as anticancer agents. In addition, their structure-activity relationships are represented in the schemes indicating the fragment or groups that are essential for the enhanced anticancer activities. Purine and pyrimidines combined with other heterocyclic compounds have resulted in many novel anticancer molecules that address the challenges of drug resistance. The purine and pyrimidine derivatives showed significantly enhanced anticancer activities against targeted receptor proteins with numerous compounds with an IC50 value in the nanomolar range. The review will support medicinal chemists and contribute in progression and development of synthesis of more potent chemotherapeutic drug candidates to mitigate the burden of this dreadful disease.

Exploring the Antiproliferative Potency of Pyrido[2,3-d]Pyrimidine Derivatives: Studies on Design, Synthesis, Anticancer Evaluation, SAR, Docking, and DFT Calculations

Herein, an efficient method for the synthesis of a new series of pyrido[2,3-d]pyrimidine derivatives has been adopted through the reaction of hydrazinyl pyrido[2,3-d] pyrimidine derivative (1) with different electrophilic species, such as ethyl cyanoacetate and different 1,3 diketone derivatives, gave the corresponding derivatives (2-5). Meanwhile, pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidines (6-11) were synthesized via reaction of hydrazine derivative 1 with phenylisothiocyanate, potassium thiocyanate, and carbon disulfide. Compound 1 was also submitted to react with different carbonyl compounds to afford pyrido-pyrimidine derivatives (12-15). All the newly synthesized compounds were tested in vitro for their antiproliferative activities against HCT-116 and MCF-7 cell lines. Compounds 2, 3, 7, and 8 displayed very strong inhibitory activity against the two cell lines compared with the standard drug doxorubicin. Furthermore, a docking study of the most active compounds was performed with the thymidylate synthase enzyme (PDB: Code 6qxg). Moreover, DFT calculation was carried out for the most biologically active compounds and a reference drug (Doxorubicin) using the B3LYP/6-31G+(d,p) level of theory. The calculated EHOMO and ELUMO energies were used to calculate the global reactivity parameters. Finally, Molecular electrostatic potential (MEP) and structure activity relationship (SAR) were studied to correlate the relation between chemical structure and reactivity.

Dihydroazolopyrimidines: Past, Present and Perspectives in Synthesis, Green Chemistry and Drug Discovery

Dihydroazolopyrimidines are an important class of heterocycles that are isosteric to natural purines and are therefore of great interest primarily as drug-like molecules. In contrast to the heteroaromatic analogs, synthetic approaches to these compounds were developed much later, and their chemical properties and biological activity have not been studied in detail until recently. In the review, different ways to build dihydroazolopyrimidine systems from different building blocks are described - via the initial formation of a partially hydrogenated pyrimidine ring or an azole ring, as well as a one-pot assembly of azole and azine fragments. Special attention is given to modern approaches: multicomponent reactions, green chemistry, and the use of non-classical activation methods. Information on the chemical properties of dihydroazolopyrimidines and the prospects for their use in the design of drugs of various profiles are also summarized in this review.

Three Component One-Pot Synthesis and Antiproliferative Activity of New [1,2,4]Triazolo[4,3-a]pyrimidines

A series of new [1,2,4]triazolo[4,3-a]pyrimidine derivatives was prepared using a one-pot three-component synthesis from 5-amino-1-phenyl-1H-1,2,4-triazoles, aromatic aldehydes and ethyl acetoacetate. The compound structures were confirmed by IR, ¹H-NMR, ¹³C-NMR, HRMS and X-ray analyses. The biological activity of these compounds as antitumor agents was evaluated. Their antitumor activities against cancer cell lines (MDA-MB-231 and MCF-7) were tested by the MTT in vitro method. Among them, compounds 4c and 4j displayed the best antitumor activity with IC₅₀ values of 17.83 μM and 19.73 μM against MDA-MB-231 and MCF-7 cell lines, respectively, compared to the Cisplatin reference.

(2-Hydroxy-3-Methoxybenzylidene)thiazolo[3,2-a]pyrimidines: Synthesis, Self-Assembly in the Crystalline Phase and Cytotoxic Activity

A series of new 2-hydroxy-3-methoxybenzylidenethiazolo[3,2-a]pyrimidines with different aryl substituents at the 5 position are synthesized and characterized by ¹H/ ¹³C NMR and IR-spectroscopy and mass-spectrometry, as well as single crystal X-ray diffraction (SCXRD). It was demonstrated that the type of hydrogen bonding can play a key role in the chiral discrimination of these compounds in the crystalline phase. The hydrogen bond of the O-H...N type leads to 1D supramolecular heterochiral chains or conglomerate crystallization in the case of the formation of homochiral chains. The hydrogen bond of O-H...O type gave racemic dimers, which are packed into 2D supramolecular layers with a parallel or angular dimers arrangement. Halogen bonding of the N...Br or O...Br type brings a new motif into supramolecular self-assembly in the crystalline phase: the formation of 1D supramolecular homochiral chains instead 2D supramolecular layers. The study of cytotoxicity against various tumor cells in vitro was carried out. It was found that 2-hydroxy-3-methoxybenzylidenethiazolo[3,2-a]pyrimidines with 3-nitrophenyl substituent at C5 carbon atom demonstrated a high efficiency against M-HeLa (cervical adenocarcinoma) and low cytotoxicity against normal liver cells.

New benzothienopyrimidine derivatives as dual EGFR/ARO inhibitors: Design, synthesis, and their cytotoxic effect on MCF-7 breast cancer cell line

New cytotoxic agents based on benzothienopyrimidine scaffold were designed, synthesized, and evaluated against the MCF-7 breast cancer line in comparison to erlotinib and letrozole as reference drugs. Eight compounds demonstrated up to 20-fold higher anticancer activity than erlotinib, and five of these compounds were up to 11-fold more potent than letrozole in MTT assay. The most promising compounds were evaluated for their inhibitory activity against EGFR and ARO enzymes. Compound 12, which demonstrated potent dual EGFR and ARO inhibitory activity with IC₅₀ of 0.045 and 0.146 µM, respectively, was further evaluated for caspase-9 activation, cell cycle analysis, and apoptosis. The results revealed that the tested compound 12 remarkably induced caspase-9 activation (IC₅₀  = 16.29 ng/ml) caused cell cycle arrest at the pre-G₁ /G₁ phase and significantly increased the concentration of cells at both early and late stage of apoptosis. In addition, it showed a higher safety profile on normal MCF-10A cells, and higher antiproliferative activity on cancer cells (IC₅₀  = 8.15 µM) in comparison to normal cells (IC₅₀  = 41.20 µM). It also revealed a fivefold higher selectivity index than erlotinib towards MCF-7 cancer cells. Docking studies were performed to rationalize the dual inhibitory activity of compound 12.

Design, synthesis and antiproliferative evaluation of new tricyclic fused thiazolopyrimidines targeting topoisomerase II: Molecular docking and apoptosis inducing activity

A novel series of thiazolopyrimidines and fused thiazolopyrimidines was designed and synthesized as topoisomerase II alpha inhibitors. All synthesized compounds were screened by the National Cancer Institute (NCI), Bethesda, USA for anticancer activity against 60 human cancer cell lines representing the following cancer types: leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate, and breast cancers. Compound 3a was found to be the most potent inhibitor on renal cell line (A-498) causing 83.03% inhibition (IC₅₀ = 1.89 μM). DNA-flow cytometric analysis showed that compound 3a induce cell cycle arrest at G2/M phase leading to cell proliferation inhibition and apoptosis. Moreover, fused thiazolopyrimidines 3a showed potent topoisomerase II inhibitory activity (IC₅₀ = 3.19 μM) when compared with reference compound doxorubicin (IC₅₀ = 2.67 μM). Docking study of all the synthesized compounds showed that compound 3a interacts in a similar pattern to etoposide and stabilizing the topoisomerase cleavage complex (Top2-cc) that accounts for its high potency.

Synthesis of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines

A series of 3(2)-phosphonylated thiazolo[3,2-a]oxopyrimidines was synthesized for the first time by the reactions of chloroethynylphosphonates with unsubstituted and 5(6)-substituted 2-thiouracils. The reaction of chloroethynylphosphonates with 6-substituted 2-thiouracils bearing electron-donor groups (CH₃, Ph) proceeded with high regioselectivity involving the cyclization through the N³-nitrogen atom to form new 3-phosphonylated thiazolo[3,2-a]-5-oxopyrimidines with good yield. In the case of unsubstituted and 5-methyl-2-thiouracils, cyclization occurred predominantly through the N¹ atom and partially via the N³-nitrogen atom to form a mixture of the corresponding thiazolo[3,2-a]-7- and 5-oxopyrimidines. A dramatic change in the reaction regioselectivity was observed in the case of 6-trifluoromethyl-2-thiouracil that afforded 2- and 3-phosphonylated 5-oxothiazolopyrimidines in a 1:1 ratio.

Regioselective convergent synthesis of 2-arylidene thiazolo[3,2-a]pyrimidines as potential anti-chikungunya agents

Convergent and convenient regioselective synthesis of novel thiazolo[2,3-a]pyrimidine derivatives was accomplished using the one-pot reaction of 6-ethylthiouracil, bromoacetic acid, anhydrous sodium acetate, acetic anhydride, acetic acid and suitable aldehyde. X-ray crystallographic study reveals the presence of the Z configuration of only one regioisomer confirmed by computational studies as being the most likely isomer present.

Convergent and convenient regioselective synthesis of novel thiazolo[2,3-a]pyrimidines was accomplished using the one-pot reaction of 6-ethylthiouracil, bromoacetic acid, anhydrous sodium acetate, acetic anhydride, acetic acid and suitable aldehyde.

Synthesis and antitumor activity of isolongifoleno[7,8-d]thiazolo[3,2-a]pyrimidine derivatives via enhancing ROS level

A series of novel isolongifoleno[7,8-d]thiazolo[3,2-a]pyrimidine derivatives (4a-4x) were synthesized from isolongifolanone according fragment-based design strategy, and their anticancer activity against human aortic smooth muscle cells (HASMC), human breast cancer (MCF-7) cells, human cervical cancer (HeLa) cells, and human liver cancer (HepG2) cells were investigated. Results of the anticancer activity illustrated that most of the compounds showed potent antitumor activity and compound 4i proved to be the most active derivative with IC₅₀ values of 0.33 ± 0.24 (for MCF-7 cells), 0.52 ± 0.13 (for HeLa cells), and 3.09 ± 0.11 μM (for HepG2 cells), respectively. Moreover, we assessed the effects of 4i on cell apoptosis, cell cycle distribution, mitochondrial membrane potential, and reactive oxygen species (ROS) generation. The results indicated that compound 4i altered mitochondrial membrane potential and produced ROS leading to cell apoptosis of MCF-7 cells in a dose-dependent manner, however, without affecting cell cycle progression. These findings suggested that 4i was an effective compound and provided a promising candidate for anticancer drugs.

Synthesis and biological screening of new thiazolo[4,5-d]pyrimidine and dithiazolo[3,2-a:5',4'-e]pyrimidinone derivatives as antimicrobial, antiquorum-sensing and antitumor agents

New thiazolopyrimidine and dithiazolopyrimidinone derivatives 2-11 were synthesized and estimated for antimicrobial activity against S. aureus, B. cereus, E. coli, C. albicans, A. fumigatus and A. terreus. The attained results proved that 4, 8a and 11g have significant effectiveness against S. aureus and B. cereus. On the other hand, 7, 10b, 10c and 11h exhibited prominent activity against B. cereus, whereas 8a, 10b and 11g were proved to be active against E. coli. From another point of view, 4 and 8a exhibited promising efficacy against A. fumigatus and A. terreus; moreover, 8a showed outstanding efficacy against C. albicans. Quorum-sensing inhibitory activity of the new compounds was esteemed against C. violaceum, where 7, 8a, 9b, 10a-c, 11d and 11g have acceptable efficacy. In vitro antitumor efficacy of the same compounds against HepG2, HCT-116 and MCF-7 cancer cell lines was also tested. Compounds 4 and 11h showed enhanced effectiveness against the three cell lines, whereas 10b displayed eminent activity against HCT-116 and MCF-7 cells. Moreover, 11a was found to have outstanding activity against MCF-7 cells, while 11i showed promising efficacy against HepG2 cells. The in vitro active antitumor compounds were evaluated for in vivo antitumor effectiveness against EAC in mice, as well as in vitro cytotoxicity against WI38 and WISH normal cells. Results manifested that 4 has the strongest in vivo activity, and that all investigated analogs are less cytotoxic than 5-FU against both normal cell lines. DNA-binding affinity of the active compounds was examined, where 4, 8a, 10c, 11d and 11g,h displayed strong affinity. In silico studies proved that majority of the analyzed compounds are in conformity with the optimum needs for good oral absorption.