Design, synthesis and antibacterial evaluation of 2,4-disubstituted-6-thiophenyl-pyrimidines

Magnolol as an Antibacterial Agent Against Drug-resistant Bacteria Targeting Filamentous Temperature-sensitive Mutant Z

The emergence of multiple drug-resistant bacteria poses critical health threats worldwide. It is urgently needed to develop potent and safe antibacterial agents with novel bactericidal mechanisms to treat these infections. In this study, magnolol was identified as a potential bacterial cell division inhibitor by a cell-based screening approach. This compound showed good antibacterial activity against a number of Gram-positive pathogens (minimum inhibitory concentration 8-16 µg/mL) including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. Further results obtained from biochemical experiments demonstrated that magnolol could markedly disrupt GTPase activity and filamentous temperature-sensitive mutant Z (FtsZ) polymerization, consistent with the impediment to cell division in the bacteria tested. The in vivo antibacterial activity of magnolol was evaluated with a Galleria mellonella larvae model. The results showed that magnolol significantly increased the survival rate of larvae infected with methicillin-resistant S. aureus. The interaction pattern of magnolol with FtsZ was investigated through molecular docking. The finding may offer meaningful insights into the mechanism of action of the compound. The results point to magnolol as a promising antimicrobial compound that inhibits cell division by affecting FtsZ polymerization and has the potential to be developed into an effective antimicrobial drug by further structure modification.

Enhancement of GTP hydrolysis and inhibition of polymerization of the cell division protein FtsZ by an N-heterocyclic imine derivative impede growth and biofilm formation in Streptococcus pneumoniae

FtsZ polymerizes to form a cytokinetic Z-ring at the mid-cell and coordinates the partitioning of a bacterial cell. Its crucial role in bacterial cell division and widely conserved nature makes it a promising target for antibacterial drugs. Streptococcus pneumoniae, a prevalent respiratory pathogen, is acquiring antimicrobial resistance at an alarming rate, highlighting the need for developing potent anti-pneumococcal agents. In this work, we identified the FtsZ-inhibitory property of an N- heterocyclic imine derivative, 3-methyl-2-(3-(p-tolyl)-1,3-thiazetidin-2-ylidene)amino-6-trifluoromethoxy-benzo[d]thiazolium trifluoromethanesulfonate (TTMB). TTMB inhibited the growth of S. pneumoniae, Staphylococcus aureus, Bacillus subtilis, Vibrio cholerae, Staphylococcus saprophyticus, and Mycobacterium smegmatis, indicating its broad-spectrum antibacterial activity. Further, TTMB inhibited biofilm formation by the pathogenic strain of S. pneumoniae. TTMB destroyed the Z-ring in S. pneumoniae and B. subtilis. The compound binds to purified FtsZ, increases the GTPase activity of FtsZ, and inhibits FtsZ assembly. FtsZ forms short and thin polymers and aggregates in the presence of TTMB. Importantly, TTMB exhibited low cytotoxicity to mammalian cells and did not inhibit tubulin polymerization or the activity of metabolic enzymes like alkaline phosphatase and alcohol dehydrogenase, suggesting its safety for mammalian systems. The dual-acting property of TTMB, targeting both planktonic and biofilm-forming S. pneumoniae, makes it a promising antibacterial agent.

Study of the antimicrobial activity of carvacrol and its mechanism of action against drug-resistant bacteria

Drug-resistant bacterial infections have been one of the critical health issues encountered worldwide currently because most conventional antibiotics are losing their effectiveness in clinical treatments. It is thus urgently to identify new antibiotics or alternatives against drug-resistant bacteria. For this purpose, we attempted to seek active compounds from commercially available natural products, which may be one of the fast-tracks to address the drug-resistant bacterial infections. In the present study, we investigated the antibacterial activity, antibacterial mechanism and synergistic effects of carvacrol against a panel of drug-resistant bacteria, including some clinical isolates. The results show that carvacrol (cymophenol), a monoterpenoid phenol, has excellent antibacterial activity. The MIC values against the bacteria examined are found to be 4-16 μg/mL. Our results also suggested that carvacrol might not likely to induce drug-resistance. More importantly, when carvacrol combined with first-line antibiotics, it exhibited good synergistic effects against drug-resistant bacteria. Moreover, in morphological studies, carvacrol could cause B. subtilis 168 elongation and S. aureus BAA-41 enlargement, which may suggest an antibacterial mechanism possibly correlated with the inhibition of bacterial cell division. We further demonstrated that carvacrol facilitated the polymerization of FtsZ that is a critically important protein for regulating bacterial cell division. Furthermore, molecular modeling predicted that carvacrol could interact with T7-loop of FtsZ. The findings of this study suggest that carvacrol may be a potential inhibitor of FtsZ and it could be utilized to combat drug-resistant bacteria in combination with existing antibiotics.

Sulfoxidation of pyrimidine thioate derivatives and study their biological activities

In a quest to innovate biologically active molecules, the benzoylation of 4,6-dimethylpyrimidine-2-thiol hydrochloride (1) with benzoyl chloride derivatives was employed to produce a series of pyrimidine benzothioate derivatives (2-5). Subsequent sulfoxidation of these derivatives (2-5) using hydrogen peroxide and glacial acetic acid yielded a diverse array of pyrimidine sulfonyl methanone derivatives (6-9). In parallel, the sulfoxidation of pyrimidine sulfonothioates (10-12) yielded sulfonyl sulfonyl pyrimidines (13-15), originating from the condensation of compound 1 with sulfonyl chloride derivatives. The newly synthesized compounds underwent characterization via FT-IR, NMR, mass spectrometry, and elemental analyses. Biological screenings unveiled interesting properties: compounds 1 and 6 exhibited significant antimicrobial potency against S. epidermidis and S. haemolyticus, whereas compound 11 showed distinct insensitivity. Excitingly, compounds 12 and 6 showcased robust antioxidant activity by efficiently scavenging DPPH• radical, underscoring their potential in oxidative stress mitigation. Notably, compounds 10 and 12 displayed promising anti-tumor effects, with compound 12 demonstrating superior efficacy against the MCF-7 breast cancer cell line compared to compound 10. The study revealed a spectrum of biological activities across the synthesized derivatives, with modifications often resulting in diminished bioactivity compared to the parent compound 1. These findings shed light on the intricate relationship between chemical modifications and biological properties, offering valuable insights for future drug discovery endeavors.

Discovery of Novel Pyrimidine Based Small Molecule Inhibitors as VEGFR-2 Inhibitors: Design, Synthesis, and Anti-cancer Studies

BACKGROUND

Receptor tyrosine kinases (RTKs) are potent oncoproteins in cancer that, when mutated or overexpressed, can cause uncontrolled growth of cells, angiogenesis, and metastasis, making them significant targets for cancer treatment. Vascular endothelial growth factor receptor 2 (VEGFR2), is a tyrosine kinase receptor that is produced in endothelial cells and is the most crucial regulator of angiogenic factors involved in tumor angiogenesis. So, a series of new substituted N-(4-((2-aminopyrimidin-5-yl)oxy)phenyl)-N-phenyl cyclopropane- 1,1-dicarboxamide derivatives as VEGFR-2 inhibitors have been designed and synthesized.

METHODS

Utilizing H-NMR, C13-NMR, and mass spectroscopy, the proposed derivatives were produced and assessed. HT-29 and COLO-205 cell lines were used for the cytotoxicity tests. The effective compound was investigated further for the Vegfr-2 kinase inhibition assay, cell cycle arrest, and apoptosis. A molecular docking examination was also carried out with the Maestro-12.5v of Schrodinger.

RESULTS

In comparison to the reference drug Cabozantinib (IC50 = 9.10 and 10.66 μM), compound SP2 revealed promising cytotoxic activity (IC50 = 4.07 and 4.98 μM) against HT-29 and COLO-205, respectively. The synthesized compound SP2 showed VEGFR-2 kinase inhibition activity with (IC50 = 6.82 μM) against the reference drug, Cabozantinib (IC50 = 0.045 μM). Moreover, compound SP2 strongly induced apoptosis by arresting the cell cycle in the G1 phase. The new compounds' potent VEGFR-2 inhibitory effect was noted with key amino acids Asp1044, and Glu883, and the hydrophobic interaction was also observed in the pocket of the VEGFR-2 active site by using a docking study.

CONCLUSION

The results demonstrate that at the cellular and enzyme levels, the synthetic compounds SP2 are similarly effective as cabozantinib. The cell cycle and apoptosis data demonstrate the effectiveness of the suggested compounds. Based on the findings of docking studies, cytotoxic effects, in vitro VEGFR-2 inhibition, apoptosis, and cell cycle arrest, this research has given us identical or more effective VEGFR-2 inhibitors.

In vitro and in vivo evaluation of novel ursolic acid derivatives as potential antibacterial agents against methicillin-resistant Staphylococcus aureus (MRSA)

The misuse and abuse of antibiotics have led to the increase of drug resistance and the emergence of multi-drug resistant bacteria. Therefore, it is an urgent need to develop novel antimicrobial agents to address this problem. Natural products (NPs) could provide an effective strategy for the discovery of drug due to their wide range of source and biological activities. Ursolic acid (UA) is a naturally occurring compound known for its wide range of biological properties. In this study, a series of UA derivatives were rationally designed and synthesized by incorporating antibacterial potential fragments of benzenesulfonamide and indole, with the aim of obtaining novel UA derivatives for the treatment of bacterial infections. Based on the preliminary screening, UA derivatives 27 (yield of 26 %), containing 4-chlorobenzenesulfonamide and 6-carboxyindole pharmacophores, as well as 34 (yield of 42 %), containing 4-carboxybenzenesulfonamide and unsubstituted indole pharmacophores, were identified as promising antibacterial agents against Staphylococcus aureus, especially for methicillin-resistant Staphylococcus aureus (MRSA), possessing MICs of 1 μM. Furthermore, both of them also displayed low hemolytic activity, non-resistance, and low-toxicity to mammalian cells. In addition, further mechanistic studies revealed that 27 and 34 were able to inhibit and eliminate MRSA biofilm formation, affecting the permeability of bacterial cell membrane, leading to increase intracellular reactive oxygen species (ROS) and ultimately inducing bacterial death. Notably, 27 and 34 also showed promising in vivo efficacy against MRSA in a mouse wound model. These results suggested that 27 and 34 should have promising applications against MRSA infection.

The study of honokiol as a natural product-based antimicrobial agent and its potential interaction with FtsZ protein

Multidrug resistant bacteria have been a global health threat currently and frontline clinical treatments for these infections are very limited. To develop potent antibacterial agents with new bactericidal mechanisms is thus needed urgently to address this critical antibiotic resistance challenge. Natural products are a treasure of small molecules with high bioactive and low toxicity. In the present study, we demonstrated that a natural compound, honokiol, showed potent antibacterial activity against a number of Gram-positive bacteria including MRSA and VRE. Moreover, honokiol in combination with clinically used β-lactam antibiotics exhibits strong synergistic antimicrobial effects against drug-resistant S. aureus strains. Biochemical studies further reveal that honokiol may disrupt the GTPase activity, FtsZ polymerization, cell division. These biological impacts induced by honokiol may ultimately cause bacterial cell death. The in vivo antibacterial activity of honokiol against S. aureus infection was also verified with a biological model of G. mellonella larvae. The in vivo results support that honokiol is low toxic against the larvae and effectively increases the survival rate of the larvae infected with S. aureus. These findings demonstrate the potential of honokiol for further structural advancement as a new class of antibacterial agents with high potency against multidrug-resistant bacteria.

Heterocyclic pyrimidine derivatives as promising antibacterial agents

Antibiotic resistance is a growing public health concern. The quest to understand the underlying mechanisms of drug resistance needs to be accompanied by an expanded arsenal of drugs. This calls for the development of new compounds with anti-bacterial properties. The ease of functionalization of the pyrimidine core, to produce structurally distinct compound libraries, has made pyrimidine a privileged structure for identifying anti-bacterial hits. The activity of pyrimidine derivatives can be attributed to the various subunits linked with the main core, especially at C-2 or C-4 or C-6. Particularly, presence of NH2 attached to C-2 of the pyrimidine nucleus has been shown to enhance the anti-bacterial activity against pathogenic Gram-positive and Gram-negative bacteria. The diversity of synthetic routes used for the synthesis of such compounds, the reported biological activities, and a growing need to develop novel anti-bacterial agents warrant a review that presents recent reports on the synthesis and anti-bacterial activities of pyrimidine-containing compounds.

Design and synthesis of fascaplysin derivatives as inhibitors of FtsZ with potent antibacterial activity and mechanistic study

The increase in antibiotic resistance has made it particularly urgent to develop new antibiotics with novel antibacterial mechanisms. Inhibition of bacterial cell division by disrupting filamentous temperature-sensitive mutant Z (FtsZ) function is an effective and promising approach. A series of novel fascaplysin derivatives with tunable hydrophobicity were designed and synthesized here. The in vitro bioactivity assessment revealed that these compounds could inhibit the tested Gram-positive bacteria including methicillin-resistant S. aureus (MRSA) (MIC = 0.049-25 μg/mL), B. subtilis (MIC = 0.024-12.5 μg/mL) and S. pneumoniae (MIC = 0.049-50 μg/mL). Among them, compounds B3 (MIC = 0.098 μg/mL), B6 (MIC = 0.098 μg/mL), B8 (MIC = 0.049 μg/mL) and B16 (MIC = 0.098 μg/mL) showed the best bactericidal activities against MRSA and no significant tendency to trigger bacterial resistance as well as rapid bactericidal properties. The cell surface integrity of bacteria was significantly disrupted by hydrophobic tails of fascaplysin derivatives. Further studies revealed that these highly active amphiphilic compounds showed low hemolytic activity and cytotoxicity to mammalian cells. Preliminary mechanistic exploration suggests that B3, B6, B8 and B16 are potent FtsZ inhibitors to promote FtsZ polymerization and inhibit GTPase activity of FtsZ, leading to the death of bacterial cells by inhibiting bacterial division. Molecular docking simulations and structure-activity relationship (SAR) study reveal that appropriate increase in the hydrophobicity of fascaplysin derivatives and the addition of additional hydrogen bonds facilitated their binding to FtsZ proteins. These amphiphilic fascaplysin derivatives could serve as a novel class of FtsZ inhibitors, which not only gives new prospects for the application of compounds containing this skeleton but also provides new ideas for the discovery of new antibiotics.

Models versus pathogens: how conserved is the FtsZ in bacteria?

Combating anti-microbial resistance by developing alternative strategies is the need of the hour. Cell division, particularly FtsZ, is being extensively studied for its potential as an alternative target for anti-bacterial therapy. Bacillus subtilis and Escherichia coli are the two well-studied models for research on FtsZ, the leader protein of the cell division machinery. As representatives of gram-positive and gram-negative bacteria, respectively, these organisms have provided an extensive outlook into the process of cell division in rod-shaped bacteria. However, research on other shapes of bacteria, like cocci and ovococci, lags behind that of model rods. Even though most regions of FtsZ show sequence and structural conservation throughout bacteria, the differences in FtsZ functioning and interacting partners establish several different modes of division in different bacteria. In this review, we compare the features of FtsZ and cell division in the model rods B. subtilis and E. coli and the four pathogens: Staphylococcus aureus, Streptococcus pneumoniae, Mycobacterium tuberculosis, and Pseudomonas aeruginosa. Reviewing several recent articles on these pathogenic bacteria, we have highlighted the functioning of FtsZ, the unique roles of FtsZ-associated proteins, and the cell division processes in them. Further, we provide a detailed look at the anti-FtsZ compounds discovered and their target bacteria, emphasizing the need for elucidation of the anti-FtsZ mechanism of action in different bacteria. Current challenges and opportunities in the ongoing journey of identifying potent anti-FtsZ drugs have also been described.

Potential Nitrogen-Based Heterocyclic Compounds for Treating Infectious Diseases: A Literature Review

Heterocyclic compounds are considered as one of the major and most diverse family of organic compounds. Nowadays, the demand for these compounds is increasing day-by-day due to their enormous synthetic and biological applications. These heterocyclic compounds have unique antibacterial activity against various Gram-positive and Gram-negative bacterial strains. This review covers the antibacterial activity of different heterocyclic compounds with nitrogen moiety. Some of the derivatives of these compounds show excellent antibacterial activity, while others show reasonable activity against bacterial strains. This review paper aims to bring and discuss the detailed information on the antibacterial activity of various nitrogen-based heterocyclic compounds. It will be helpful for the future evolution of diseases to synthesize new and effective drug molecules.

The Anti-MRSA Activity of Phenylthiazoles: A Comprehensive Review

Antimicrobial resistance is an aggravating global issue therefore it has been under extensive research in an attempt to reduce the number of antibiotics that are constantly reported as obsolete jeopardizing the lives of millions worldwide. Thiazoles possess a reputation as one of the most diverse biologically active nuclei, and phenylthiazoles are no less exceptional with an assorted array of biological activities such as anthelmintic, insecticidal, antimicrobial, antibacterial, and antifungal activity. Recently phenyl thiazoles came under the spotlight as a scaffold having strong potential as an anti-MRSA lead compound. It is a prominent pharmacophore in designing and synthesizing new compounds with antibacterial activity against multidrug-resistant bacteria such as MRSA, which is categorized as a serious threat pathogen, that exhibited concomitant resistance to most of the first-line antibiotics. MRSA has been associated with soft tissue and skin infections resulting in high death rates, rapid dissemination, and loss of millions of dollars of additional health care costs. In this brief review, we have focused on the advances of phenylthiazole derivatives as potential anti-MRSA from 2014 to 2021. The review encompasses the effect on biological activity due to combining this molecule with various synthetic pharmacophores. The physicochemical aspects were correlated with the pharmacokinetic properties of the reviewed compounds to reach a structure-activity relationship profile. Lead optimization of phenyl thiazole derivatives has additionally been outlined where the lipophilicity of the compounds was balanced with the metabolic stability and oral solubility to aid the researchers in medicinal chemistry, design, and synthesizing effective anti- MRSA phenylthiazoles in the future.

Acid-controlled multicomponent selective synthesis of 2,4,6-triaryl pyridines and pyrimidines by using hexamethyldisilazane as a nitrogen source under microwave irradiation

An efficient and general protocol for the synthesis of functionalized 2,4,6-triaryl pyridines and pyrimidines was developed from commercially available aromatic ketones, aldehydes and hexamethyldisilazane (HMDS) as a nitrogen source under microwave irradiation. In this multicomponent synthetic route, Lewis acids play an important role in selectively synthesizing six-membered heterocycles, including pyridines (1N) and pyrimidines (2N), by involving [2 + 1 + 2 + 1] or [2 + 1 + 1 + 1 + 1] annulated processes.

Design, synthesis and biological evaluation of biphenyl-benzamides as potent FtsZ inhibitors

The rapid emergence of antibiotic resistance has become a prevalent threat to public health, thereby development of new antibacterial agents having novel mechanisms of action is in an urgent need. Targeting at the cytoskeletal cell division protein filamenting temperature-sensitive mutant Z (FtsZ) has been validated as an effective and promising approach for antibacterial drug discovery. In this study, a series of novel biphenyl-benzamides as FtsZ inhibitors has been rationally designed, synthesized and evaluated for their antibacterial activities against various Gram-positive bacteria strains. In particular, the most promising compound 30 exhibited excellent antibacterial activities, especially against four different Bacillus subtilis strains, with an MIC range of 0.008 μg/mL to 0.063 μg/mL. Moreover, compound 30 also showed good pharmaceutical properties with low cytotoxicity (CC₅₀ > 20 μg/mL), excellent human metabolic stability (T_1/2 = 111.98 min), moderate pharmacokinetics (T_1/2 = 2.26 h, F = 61.2%) and in vivo efficacy, which can be identified as a promising FtsZ inhibitor worthy of further profiling.

Design, Synthesis, Antibacterial Evaluations and In Silico Studies of Novel Thiosemicarbazides and 1,3,4-Thiadiazoles

The emergence of drug-resistant bacterial strains continues to be one of the major challenges of medicine. For this reason, the importance of searching for novel structures of antibacterial drugs chemically different from the currently known antibiotics is still of great importance. In this study, we synthesized the thiosemicarbazide and 1,3,4-thiadiazole derivatives and tested them for antibacterial activity. In in vitro tests, we examined the activity of the synthesized substances against Gram-positive and Gram-negative bacteria strains. While all 1,3,4-thiadiazoles tested lacked significant activity, the antimicrobial response of the thiosemicarbazides was moderate and it was also dependent on the type and position of the substituent on the phenyl ring. The highest activity towards all Gram-positive bacteria strains was shown by all three linear compounds containing the trifluoromethylphenyl group in the structure. The MIC (minimum inhibitory concentration) values were in the range of 3.9–250 µg/mL. Additionally, we try to explain the mechanism of the antibacterial activity of the tested compounds using the molecular docking to DNA gyrase and topoisomerase IV, following previous reports on the molecular basis of the activity of thiosemicarbazides. Docking simulations allow the purposing dual mechanism of the antibacterial activity of the synthesized compounds through inhibition of topoisomerase IV DNA gyrase with the moderate prevalence of the topoisomerase pathway.

Thiophene-containing compounds with antimicrobial activity

Thiophene, as a member of the group of five-membered heterocycles containing one heteroatom, is one of the simplest heterocyclic systems. Many synthetic strategies allow the accurate positioning of various functionalities onto the thiophene ring. This review provides a comprehensive, systematic and detailed account of the developments in the field of antimicrobial compounds featuring at least one thiophene ring in their structure, over the last decade.

Selective Synthesis of Substituted Pyridines and Pyrimidines through Cascade Annulation of Isopropene Derivatives

Diverse substituted pyridines and pyrimidines with high selectivity were obtained using a concise and efficient protocol developed herein. The reaction proceeds via metal-free cascade annulation of isopropene derivatives. Using isopropene derivatives as C3 synthons, NH₄I as the "N" source, and formaldehyde or dimethyl sulfoxide as the carbon source, this reaction realizes the efficient formation of intermolecular C-N and C-C bonds.

Synthesis and Antifungal and Insecticidal Activities of Novel N-Phenylbenzamide Derivatives Bearing a Trifluoromethylpyrimidine Moiety

Seventeen novel N-phenylbenzamide derivatives bearing a trifluoromethylpyrimidine moiety were synthesized via four-step reactions. Their antifungal and insecticidal properties were evaluated. Antifungal test results demonstrated that some of the synthesized compounds showed better in vitro bioactivities against Phomopsis sp., Botryosphaeria dothidea (B. dothidea), and Botrytis cinerea (B. cinerea) at 50 μg/mL than pyrimethanil. Unfortunately, the synthesized compounds revealed lower insecticidal activities against Spodoptera frugiperda (S. frugiperda) and Mythimna separata (M. separata) at 500 μg/mL than chlorantraniliprole.

Targeting the Achilles Heel of FtsZ: The Interdomain Cleft

Widespread antimicrobial resistance among bacterial pathogens is a serious threat to public health. Thus, identification of new targets and development of new antibacterial agents are urgently needed. Although cell division is a major driver of bacterial colonization and pathogenesis, its targeting with antibacterial compounds is still in its infancy. FtsZ, a bacterial cytoskeletal homolog of eukaryotic tubulin, plays a highly conserved and foundational role in cell division and has been the primary focus of research on small molecule cell division inhibitors. FtsZ contains two drug-binding pockets: the GTP binding site situated at the interface between polymeric subunits, and the inter-domain cleft (IDC), located between the N-terminal and C-terminal segments of the core globular domain of FtsZ. The majority of anti-FtsZ molecules bind to the IDC. Compounds that bind instead to the GTP binding site are much less useful as potential antimicrobial therapeutics because they are often cytotoxic to mammalian cells, due to the high sequence similarity between the GTP binding sites of FtsZ and tubulin. Fortunately, the IDC has much less sequence and structural similarity with tubulin, making it a better potential target for drugs that are less toxic to humans. Over the last decade, a large number of natural and synthetic IDC inhibitors have been identified. Here we outline the molecular structure of IDC in detail and discuss how it has become a crucial target for broad spectrum and species-specific antibacterial agents. We also outline the drugs that bind to the IDC and their modes of action.

Design, synthesis, and cytotoxic activity of novel 2H-imidazo[1,2-c]pyrazolo[3,4-e]pyrimidine derivatives

In this study, a series of novel 2H-imidazo [1, 2-c] pyrazolo [3, 4-e] pyrimidine derivatives were designed, synthesized, and evaluated for their cytotoxic activities. The in vitro cell growth inhibition assay of the target compounds indicated their selectivity in inhibiting the proliferation of blood tumor cells (K562, U937) and solid tumor cells (HCT116, HT-29). Compound 9b exhibited the highest antiproliferative activities against K562 (IC₅₀ = 5.597 µM) and U937 (IC₅₀ = 3.512 µM). Based on the flow cytometry assays, compound 9b caused obvious induction of cell apoptosis and cell arrest at the S phase. Furthermore, western blot analysis revealed that compound 9b upregulated the expression of Bax, downregulated the levels of Bcl-2, and further activated caspase-3 in K562 cells. Therefore, compound 9b may be a potential anticancer agent that deserves further investigation.

Ethyl (S)-2-Benzamido-5-[(4,6-dimethylpyrimidin-2-yl)amino]pentanoate

Pyrimidines are compounds with a wide range of biological activities, and the synthesis of pyrimidine derivatives—useful in chemical and medicinal applications—is important in medicinal chemistry. This work shows the synthesis under microwave irradiation of the novel compound ethyl (S)-2-benzamido-5-[(4,6-dimethylpyrimidin-2-yl)amino]pentanoate (3) from (S)-N-α-benzoyl-l-arginine ethyl ester hydrochloride (1) and acetylacetone (2). Compound 3 was easily purified, obtained in moderate yield (70%), and fully characterized by UV-Vis, FTIR-ATR spectroscopy, 1H-NMR, 13C-NMR, HRMS, and EI-MS.

Synthesis and Bioactivities Study of Novel Pyridylpyrazol Amide Derivatives Containing Pyrimidine Motifs

In this study, thirteen new pyridylpyrazolamide derivatives containing pyrimidine motifs were synthesized via six-step reactions. Bioassay results showed that some of the synthesized compounds revealed good antifungal properties against Sclerotinia sclerotiorum, Phytophthora infestans, Thanatephorus cucumeris, Gibberella zeae, Fusarium oxysporum, Cytospora mandshurica, Botryosphaeria dothidea, and Phompsis sp. at 50 μg/mL, which were similar to those of Kresoxim-methyl or Pyrimethanil. Meanwhile, bioassay results indicated that the synthesized compounds showed a certain insecticidal activity against Spodoptera litura, Mythimna separata, Pyrausta nubilalis, Tetranychus urticae, Rhopalosiphum maidis, and Nilaparvata lugens at 200 μg/mL, which was lower than that of Chlorantraniliprole. To the best of our knowledge, this study is the first report on the antifungal and insecticidal activities of pyridylpyrazol amide derivatives containing a pyrimidine moiety.

Crystal structure of 4-((2-methyl-6-(trifluoromethyl)pyrimidin-4-yl)oxy)benzoic acid, C13H9F3N2O3

C13H9F3N2O3, monoclinic, P21/c (no. 14), a = 8.6952(7) Å, b = 19.6715(18) Å, c = 8.0995(8) Å, β = 110.691(3)°, V = 1296.0(2) Å3, Z = 4, R gt(F) = 0.0558, wR ref(F 2) = 0.1358, T = 298(2) K.

Exploration of carbamide derived pyrimidine-thioindole conjugates as potential VEGFR-2 inhibitors with anti-angiogenesis effect

The development of new small molecules from known structural motifs through molecular hybridization is one of the trends in drug discovery. In this connection, we have combined the two pharmacophoric units (pyrimidine and thioindole) in a single entity via molecular hybridization strategy along with introduction of urea functionality at C2 position of pyrimidine to increase the efficiency of H-bonding interactions. Among the synthesized conjugates 12a-aa, compound 12k was found to exhibit significant IC₅₀ values 5.85, 7.87, 6.41 and 10.43 μM against MDA-MB-231 (breast), HepG2 (liver), A549 (lung) and PC-3 (prostate) cancer cell lines, respectively. All these compounds were further evaluated for their inhibitory activities against VEGFR-2 protein. The results specified that among the tested compounds, 12d, 12e, 12k, 12l, 12p, 12q, 12t and 12u prominently suppressed VEGFR-2, with IC₅₀ values of 310-920 nM in association to the positive control (210 nM). Angiogenesis inhibition was evident by tube formation assay in HUVECs and cell-invasion by transwell assay. The mechanism of cellular toxicity on MDA-MB-231 was found through depolarisation of mitochondrial membrane potential, increased ROS production and subsequent DNA damage resulting in apoptosis induction. Moreover, clonogenic and wound healing assays designated the inhibition of colony formation and cell migration by 12k in a dose-dependent manner. Molecular docking studies also shown that compound 12k capably intermingled with catalytically active residues GLU-885, ASP-1046 of the VEGFR-2 through hydrogen-bonding interactions.

The cell division protein FtsZ as a cellular target to hit cystic fibrosis pathogens

Cystic fibrosis is a rare genetic disease characterized by the production of dehydrated mucus in the lung able to trap bacteria and rendering their proliferation particularly dangerous, thus leading to chronic infections. Among these bacteria, Staphylococcus aureus and Pseudomonas aeruginosa play a major role while, within emerging pathogens, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia complex species, as well as non-tuberculous mycobacteria are listed. Since a common feature of these bacteria is the high level of drug resistance, cell division, and in particular FtsZ, has been explored as a novel therapeutic target for the design of new molecules with antibacterial properties. This review summarizes and provides insight into recent advances in the discovery of compounds targeting FtsZ: the majority of them exhibit anti-staphylococcal activity, while a few were directed against the cystic fibrosis Gram negative pathogens.

Targeting Bacterial Cell Division: A Binding Site-Centered Approach to the Most Promising Inhibitors of the Essential Protein FtsZ

Binary fission is the most common mode of bacterial cell division and is mediated by a multiprotein complex denominated the divisome. The constriction of the Z-ring splits the mother bacterial cell into two daughter cells of the same size. The Z-ring is formed by the polymerization of FtsZ, a bacterial protein homologue of eukaryotic tubulin, and it represents the first step of bacterial cytokinesis. The high grade of conservation of FtsZ in most prokaryotic organisms and its relevance in orchestrating the whole division system make this protein a fascinating target in antibiotic research. Indeed, FtsZ inhibition results in the complete blockage of the division system and, consequently, in a bacteriostatic or a bactericidal effect. Since many papers and reviews already discussed the physiology of FtsZ and its auxiliary proteins, as well as the molecular mechanisms in which they are involved, here, we focus on the discussion of the most compelling FtsZ inhibitors, classified by their main protein binding sites and following a medicinal chemistry approach.

Recent Progress in the Development of Small-Molecule FtsZ Inhibitors as Chemical Tools for the Development of Novel Antibiotics

Antibiotics are potent pharmacological weapons against bacterial pathogens, nevertheless their efficacy is becoming compromised due to the worldwide emergence and spread of multidrug-resistant bacteria or "superbugs". Antibiotic resistance is rising to such dangerous levels that the treatment of bacterial infections is becoming a clinical challenge. Therefore, urgent action is needed to develop new generations of antibiotics that will help tackle this increasing and serious public health problem. Due to its essential role in bacterial cell division, the tubulin-like protein FtsZ has emerged as a promising target for the development of novel antibiotics with new mechanisms of action. This review highlights the medicinal chemistry efforts towards the identification of small-molecule FtsZ inhibitors with antibacterial activity in the last three years.

Promising antibacterial agents against multidrug resistant Staphylococcus aureus

Rapid emergence of multidrug resistant Staphylococcus aureus infections has created a critical health menace universally. Resistance to all the available chemotherapeutics has been on rise which led to WHO to stratify Staphylococcus aureus as high tier priorty II pathogen. Hence, discovery and development of new antibacterial agents with new mode of action is crucial to address the multidrug resistant Staphylococcus aureus infections. The egressing understanding of new antibacterials on their biological target provides opportunities for new therapeutic agents. This review underlines on various aspects of drug design, structure activity relationships (SARs) and mechanism of action of various new antibacterial agents and also covers the recent reports on new antibacterial agents with potent activity against multidrug resistant Staphylococcus aureus. This review provides attention on in vitro and in vivo pharmacological activities of new antibacterial agents in the point of view of drug discovery and development.

Indole-core-based novel antibacterial agent targeting FtsZ

Background

The prevalence of drug-resistant bacterial infections urges the development of new antibacterial agents that possess a mechanism of action different from traditional antibiotics. FtsZ has been recognized as a key functional protein in bacterial cell division and it is currently believed to be a potential target for the development of novel antibacterial agents.

Purpose

The primary aim of the study is to screen out an inhibitor targeting at FtsZ and followed to investigate its antibacterial activity and mode of action.

Methods

Cell-based cell division inhibitory screening assay, antimicrobial susceptibility test, minimum bactericidal concentration assay, time-killing curve determination, FtsZ polymerization assay, GTPase activity assay, and molecular modeling were performed in the present study.

Results

The screening study from a small library consisting of benzimidazole and indole derivatives discovered a compound (CZ74) with an indole-core structure. The compound exhibited strong cell division inhibitory effect. In addition, CZ74 shows high antibacterial potency against a number of tested Gram-positive bacteria, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. The minimum inhibitory concentration values obtained were within the range of 2–4 µg/mL. The results of biological study revealed that CZ74 at 2 µg/mL is able to disrupt FtsZ polymerization and inhibit GTPase activity and cell division. From molecular modeling study, CZ74 is found possibly binding into the interdomain cleft of FtsZ protein and then leads to inhibitory effects.

Conclusion

This indole-cored molecule CZ74 could be a potential lead compound and could be further developed as a new generation of antibacterial agents targeting FtsZ to combat against multidrug-resistant bacteria.

DBU-Mediated Cyclization of Acylcyclopropanecarboxylates with Amidines: Access to Polysubstituted Pyrimidines

DBU-mediated cyclization of 2-acyl-1-cyanocyclopropanecarboxylates with amidines for the synthesis of multisubstituted pyrimidine derivatives is described. This reaction gives a practical method for producing a diverse set of pyrimidines, having simple experimentation, readily available starting materials, a wide substrate scope, and very good yields.

Lipophilic efficient phenylthiazoles with potent undecaprenyl pyrophosphatase inhibitory activity

Antibiotic resistance remains a pressing medical challenge for which novel antibacterial agents are urgently needed. The phenylthiazole scaffold represents a promising platform to develop novel antibacterial agents for drug-resistant infections. However, enhancing the physicochemical profile of this class of compounds remains a challenging endeavor to address to successfully translate these molecules into novel antibacterial agents in the clinic. We extended our understanding of the SAR of the phenylthiazoles' lipophilic moiety by exploring its ability to accommodate a hydrophilic group or a smaller sized hetero-ring with the objective of enhancing the physicochemical properties of this class of novel antimicrobials. Overall, the 2-thienyl derivative 20 and the hydroxyl-containing derivative 31 emerged as the most promising antibacterial agents inhibiting growth of drug-resistant Staphylococcus aureus at a concentration as low as 1 μg/mL. Remarkably, compound 20 suppressed bacterial undecaprenyl pyrophosphatase (UppP), the molecular target of the phenylthiazole compounds, in a sub nano-molar concentration range (almost 20,000 times more potent than the lead compounds 1a and 1b). Compound 31 possessed the most balanced antibacterial and physicochemical profile. The compound exhibited rapid bactericidal activity against S. aureus, and successfully cleared intracellular S. aureus within infected macrophages. Furthermore, insertion of the hydroxyl group enhanced the aqueous solubility of 31 by more than 50-fold relative to the first-generation lead 1c.