Compounds 4j Research Articles

Design, synthesis, and antiproliferative activity of new 1,2,3-triazole/quinazoline-4-one hybrids as dual EGFR/BRAFV600E inhibitors.

A novel series of 1,2,3-triazole/quinazoline-4-one hybrids (8a-t) were designed and synthesized as dual-targeted antiproliferative agents. Compounds 8a-t were evaluated for their antiproliferative efficacy against a panel of four cancer cell lines. The results indicated that most of the evaluated compounds exhibited strong antiproliferative activity, with 8f, 8g, 8h, 8j, and 8l demonstrating the highest potency. These five compounds were investigated as EGFR and BRAFV600E inhibitors. The in vitro tests showed that compounds 8g, 8h, and 8j are strong antiproliferative agents that might work as dual EGFR/BRAFV600E inhibitors. Compounds 8g and 8h were further examined as activators of caspases 3, 8, and Bax and down-regulators of the anti-apoptotic protein Bcl2. The results indicated that the studied compounds had considerable apoptotic antiproliferative action. The investigation of the cell cycle and apoptosis revealed that compound 8g induces cell cycle arrest during the G1 phase transition. Molecular docking experiments are thoroughly examined to validate the binding interactions of the most active hybrids with the active sites of EGFR and BRAFV600E. The data indicated that the examined compounds can efficiently engage with essential amino acid residues in both kinases.

1,3-Naphthoxazine derivatives: Synthesis, in silico pharmacokinetic studies, antioxidant and photoprotective properties

Investigation into the interactions between photoprotective agents and skin can offer a precise understanding of their biological behaviors in vitro and in vivo, providing crucial insights for generating new substances. For this purpose, we designed and synthesized a series of naphthoxazine derivatives and examined their photoprotective properties. 1,3-naphthoxazine derivatives were synthesized through the multi-component reaction of 2-naphthol, arylamines and aromatic aldehydes in the presence of copper(II) trifluoromethanesulfonate (Cu(OTf)2) and (±)-Camphor-10-sulfonic acid ((±)-CSA) catalyst system under sonication. The potential of these synthesized 1,3-naphthoxazine derivatives as antioxidants and viable organic structural-based sunscreen ingredients has been investigated. Sun protection factor (SPF) assay results showed that especially compounds 4i, 4c, 4k, 4d, 4r, and 4h had remarkably high activity (23.65, 23.57, 23.04, 21.94, 20.80, and 20.26, respectively at 900 µg/mL concentration). Additionally, antioxidant activity of the synthesized compounds was evaluated and compounds 4h, 4e, 4b, and 4j exhibited the highest activities in DPPH scavenging activity assay (86.46 %, 82.83 %, 80.78 %, and 80.65 % respectively at 400 µg/mL concentration). The synthesized compounds exhibit promising characteristics for effective UV radiation absorption, suggesting their suitability for inclusion in sunscreen formulations. Cytotoxic activity of compound 4k against normal human fibroblast cell line (MRC-5) was determined by CVDK-8 method. The results revealed that the compound provided remarkable viability (87.55 %) of MRC-5 cells at concentration of 100 µM. The study explores their efficacy in providing broad-spectrum protection against UVA and UVB rays, degradation and photostability, ADMET profile, and other pharmacokinetic properties.

Novel Pyrimidine Tethered Benzamide Derivatives as Potential Anticancer Agents: Synthesis, Characterization, Molecular Docking and In vitro Cytotoxicity Evaluation

Current research work presents the synthesis, characterization, molecular docking study and in vitro cytotoxicity evaluation of novel pyrimidine-tethered benzamide derivatives as potential anticancer agents. The synthesis involved multi-steps procedure, including the synthesis of various chalcones (3a-t) with corresponding ketones (1 and 2) and substituted aldehydes (a-j), followed by pyrimidine amines (5a-t) with condensation of chalcones and guanidine and finally pyrimidinyl benzamide derivatives (8a-t) from compounds 5a-t coupling with acid chloride (7) using DIBAL-H. Synthesized compounds characterized by NMR spectroscopy and HRMS. The molecular docking studies were conducted against EGFR (6LUD) and CDK-4 (7SJ3) receptors, revealing distinct binding affinities influenced by substituent groups. Additionally, the cytotoxicity of the synthesized compounds was evaluated using the MTT assay against various cancer cell lines, including A-549 (non-small cell lung cancer), HCT-116 (colorectal cancer), PANC-1 (pancreatic cancer) and HaLa (cervical cancer), along with one normal human embryonic kidney cell line (HEK-293). Among the synthesized compounds, derivatives 8f and 8j exhibited the best anticancer activity against A-549 cells, compounds 8j and 8e showed exceptional potency against HCT-116 cells, compounds 8f and 8j demonstrated high efficacy against PANC-1 cells and compound 8h displayed remarkable potency against HaLa cells. The findings highlight the potential of these pyrimidinyl benzamide derivatives as targeted anticancer agents.

Design, synthesis, and biological evaluation of novel molecules as potent inhibitors of indoleamine 2,3-dioxygenase 1.

Tumoral immune escape is an obstacle to successful cancer therapy. Tryptophan catabolism mediated by indoleamine 2,3-dioxygenase (IDO1) is an important mechanism of peripheral immune tolerance contributing to tumoral immune resistance, and IDO1 inhibition is an active area of drug development. Several classes of small molecule-based IDO1 inhibitors have already been reported. Still, only a few compounds are currently being evaluated in various stages of clinical trials as adjuvants or in combination with chemo- and radiotherapies. In this study, a novel series of 1,2,5-oxadiazole-3-carboximidamide derivatives were designed, synthesized, and evaluated for inhibitory activities against IDO1, and their structure-activity relationship was investigated. Notably, several compounds (11c, 11j, 11o, and 11u) showed powerful anti-tumor effects in the low micromolar range. Among them, compound 11u exhibited excellent inhibitory potency against hIDO1 (IC50 = 42.2 ± 2.23nM) and in Hela cells expressing hIDO1 (IC50 = 4.35 ± 0.13nM). Combined with favorable in vitro potency, pharmacokinetic profile, and in vivo efficacy, the promising antitumor drug candidate 11u has subsequently advanced into preclinical research. These compounds provide valuable ideas and information for developing new cancer immunotherapy.

Synthesis, enzyme inhibition, and docking studies of new schiff bases of disalicylic acid methylene-based derivatives as dual-target antibacterial agents.

Bacteria have acquired resistance to almost all antibiotics currently in use due to their extensive, broad, and improper utilization over a prolonged period. DNA gyrase and DHFR exhibit significant promise as targets for antibacterial therapeutics. We have developed a series of disalicylic acid methylene/Schiff bases hybrids (6a-l) that function as antibacterial agents by targeting DNA gyrase and DHFR. The findings showed that 6a-l have significant antibacterial activity against both Gram-positive and Gram-negative bacteria, with inhibition zones (IZ) comparable to or even higher than the reference Ciprofloxacin. MIC testing revealed that 6h and 6l were 1.5 times as effective than ciprofloxacin against S. aureus. Compounds 6h and 6l had MBC values of 28 and 33nM for S. aureus, compared to Ciprofloxacin's 45nM, indicating that they are more potent bactericidal agents. The MIC values for compounds 6c, 6e, 6h, 6j, and 6l against A. flavus were between 14.50 and 19.50µM, while the MIC value for fluconazole was 11.50µM. Also, the studied compounds had MIC values between 18.20 and 22.90µM against C. albicans, while Fluconazole had a MIC value of 17.50µM. Compound 6h showed a MIC value of 1.70µM against the clinical strain S. aureus (ATCC 43300) (MRSA), making it an effective antibacterial agent. Compounds 6h, 6j, and 6l inhibited E. coli DNA gyrase with IC50 values of 79, 117, and 87nM, respectively, compared to the reference novobiocin (IC50 = 170nM). Additionally, compounds 6h and 6l, the most potent E. coli gyrase inhibitors, showed encouraging results on DHFR. Compounds 6h and 6l exhibit IC50 values of 3.80µM and 4.25µM, respectively. These values are significantly lower and hence more effective than Trimethoprim's IC50 of 5.20µM.

Natural Products-Based Anticancer Agents: Synthesis and Anticancer Activities of Funtumine Amide/Sulfonamide Derivatives.

Funtumine is a pregnene-type steroidal alkaloid exhibiting moderate anticancer activity. To discover novel natural product-based anticancer drugs, a series of novel funtumine amide/sulfonamide derivatives were papered and identified using spectroscopic techniques. Additionally, the structures of compounds 2j, 3a, and 4k were further confirmed through X-ray diffraction analysis. Biological activity experiments conducted against three cancer cell lines revealed that several of the synthesized compounds demonstrated inhibition activities comparable to or exceeding those of the commercial anticancer agent, 5-Fluorouracil. Especially compound 4i demonstrated a notably strong growth inhibitory effect on HePG2 (IC50=14.89 μM) and HCT116 (IC50=15.67 μM) cell lines, while exhibiting minimal cytotoxicity towards human normal BEAS-2B cells. Preliminary structure-activity relationships (SARs) analysis indicated that the conversion of the carbonyl group at the C-20 position of funtumine to a hydroxyl group could yield more potent compounds.

Design, Synthesis, and Evaluation of Novel Thiazole-Containing Algicides Inspired by Bacillamide A.

The pursuit of highly effective, low-toxicity, and eco-friendly algicides for controlling and eradicating harmful algal blooms (HABs) is of paramount importance. The natural allelochemical bacillamide A has displayed impressive algicidal activity against harmful algae with favorable safety profiles. However, the poor synthetic efficiency and large dose requirements of bacillamide A limit its further application. In this paper, 17 thiazole-containing bacillamide derivatives (BDs) were designed and synthesized in three linear steps as potential algicides. Eight compounds (6a, 6c, 6j, 7b, 7c, 7d, 7e, and 7g) displayed potent inhibitory effects against Prorocentrum minimum, Skeletonema costatum, and Alexandrium pacificum, and they had similar or better activity than the positive control (CuSO4) and bacillamide A. Compound 6a exhibited the most potent algicidal activity against S. costatum (half-maximal effective concentration [EC50] = 0.11 μg/mL), being 23-fold more potent than bacillamide A, 28-fold more potent than CuSO4, and 39-fold more potent than Diuron. Compound 6j exhibited significant algicidal activity against the toxic dinoflagellates P. minimum (EC50 = 1.0 μg/mL) and A. pacificum (EC50 = 0.47 μg/mL), being 3-5-fold more potent than natural bacillamide A, Diuron, and CuSO4. Micrographs and SEM images revealed that 6j induced cell wall rupture and cellular content leakage. Biochemical and physiological studies indicated that 6j might partially disrupt the antioxidant and photosynthetic systems in algal cells, resulting in morphological changes, cell wall rupture, and inclusion leakage. Our work suggests that 6j has a distinct mode of action from CuSO4 and provides a promising candidate for the development of new algicides, worthy of further investigation.

Synthesis of Paracetamol‐Appended Bis 1,2,3‐Triazole Analogues as Anti‐Inflammatory Agents

AbstractParacetamol‐based bis 1,2,3‐triazole analogues were synthesized involving copper‐catalyzed click chemistry protocol. The new compounds were characterized by 1H NMR, 13C NMR, and mass spectral techniques. All the compounds were evaluated for their in vitro anti‐inflammatory properties using diclofenac as standard reference. The compound 6b with chlorine and fluorine functions displayed outstanding activity with IC50 values of 7.34 ± 0.45 µM and 7.84 ± 0.47 µM, respectively. Compound 6g with methyl and fluorine functions displayed best activity with IC50 values of 9.34 ± 0.22 µM and 9.40 ± 0.35 µM, respectively. Compound 6i, 6k, 6f, 6a, 6e, 6h, 6j, and 6l exhibited promising activity with respect to diclofenac. Using PyRx tool, the molecular docking study against crystal structure of COX‐2 proved the binding efficacies with notable binding interactions.

Synthesis and Molecular Docking Study of Hydrazone Schiff Bases of α‐Naphthalene‐Containing Alkyl Phenyl Ether Fragment as Potent α‐Amylase and α‐Glucosidase Inhibitors

AbstractIn this study, new Schiff base derivatives of α‐naphthalene acetic acid containing alkyl phenyl ether fragment have been effectively synthesized through multistep reaction process, characterized by 1H‐NMR and 13C‐NMR spectroscopy. These derivatives have been tested for their in vitro α‐amylase and α‐glucosidase inhibitory activities. In the series, 8 compounds (2j, 2f, 2e, 2m, 2a, 2b, 2l, and 2c) exhibited promising α‐amylase inhibition with IC50 values from 5.38 ± 0.36 to 14.59 ± 0.64 µg/mL. Similarly, in the case of α‐glucosidase inhibitory activity, 10 derivatives (2e, 2f, 2j, 2m, 2b, 2c, 2i, 2d, 2a, and 2l) exhibited excellent activity having IC50 values from 6.96 ± 0.39 to 16.27 ± 0.31 µg/mL, wheras the remaining derivatives exhibited good‐to‐least antidiabetic potential. The ADME properties were calculated for all Schiff base derivatives using Swiss‐ADME web tool. Furthermore, the docking studies identified the binding modes of the compounds.

Design and Synthesis of Ester Linked 1,2,3‐Triazole Quinoline Derivatives with Pancreatic β Cells Protective Activity against Oxidative Stress and Endoplasmic Reticulum Stress for Better Management of Type II Diabetes Mellitus

AbstractUnresolved endoplasmic reticulum (ER) stress and oxidative stress lead to the pathogenesis of type II diabetes mellitus (DM). Connecting links between the ER stress and oxidative stress pathways might play an important role in treatment and pathogenesis of diabetes. Here, we used network pharmacology approach to find the target proteins linking the ER stress and oxidative stress pathways. CHOP emerged as a hub protein from our results and was targeted by 16 newly designed and synthesized ester linked 1,2,3‐triazole quinoline derivatives by molecular docking. Drug likeliness prediction studies revealed all compounds as good druggable candidates. Compounds 5b (R = H, R1 = F), 5j (R = CH3, R1 = F), 5m (R = OCH3, R1 = H), and 5n (R = OCH3, R1 = F) were found to have considerable binding energies and active site amino acid interactions with CHOP. We further showed that compounds 5b, 5m, and 5n exhibited low toxicity with more than 50% cell survival and low IC50 values. These were therefore subjected to evaluate their effects on ER stress and oxidative stress. Finally, compound 5n (R = OCH3, R1 = F) was found to alleviate ER stress and is also a good antioxidant. Identification of such targets and compounds effective in improving ER stress and oxidative stress may provide new insights in the development of therapies and management of T2DM.

Tandem Synthesis of Piriqualone and Analogues Using Deep Eutectic Solvents: Photophysical and Theoretical Insights

This study presents a sustainable chemical approach for the tandem synthesis of Piriqualone a sedative and anxiolytic drug and its analogues using a green protocol. The research investigates the ability of deep eutectic solvents (DESs) to act as catalysts as well as solvent in a tandem reaction involving metal‐free dehydrogenation and sp3 C‐H bond functionalization, leading to the formation of styryl‐heterocyclic compounds (7a‐p). These styryl derivatives were thoroughly characterized through spectral analysis and photophysical property evaluation. The relationship between chemical structure and AIE properties was particularly examined for compound 7n. Additionally, the experimental findings were corroborated by density functional theory (DFT) calculations. The structures of compounds 7j, 7p and 7fa were further validated through single crystal X‐ray diffraction (XRD) analysis.

Naphthyl-functionalized acetamide derivatives: Promising agents for cholinesterase inhibition and antioxidant therapy in Alzheimer’s disease

This study presents the synthesis and characterization of a series of 13 novel acetamides. These were subjected to Ellman’s assay to determine the efficacy of the AChE and BChE inhibitors. Finally, we report their antioxidant activity as an alternative approach for the search for drugs to treat AD. These studies revealed that compounds 1a–1k and 2l–2m were obtained in moderate yield. Four amides (1h, 1j, 1k, and 2l) were selective for one of the enzymes (BChE); thus, those that inhibited BChE were more active than the positive control (galantamine) and showed better IC50 values (3.30–5.03 µM). The theoretical free binding energies calculated by MM-GBSA indicated that all inhibitors were more stable than rivastigmine, and the inhibition mechanisms involved the entire active site: peripheral anionic site, oxyanion hole, acyl-binding pockets, and catalytic site. We examined the cytotoxicity of compounds 1h, 1j, 1k, and 2l in human dermal cells and found that they did not exhibit any toxic effects under the tested conditions. Additionally, these compounds, which also inhibited BChE, displayed mixed inhibition and did not exhibit hemolytic effects on human erythrocytes. Furthermore, the ABTS and DPPH assays indicated that, although none of the compounds showed activity in the DPPH assay, the EC50 values for radical trapping by the ABTS method showed that compounds 1a, 1d, 1e, and 1g had EC50 values lower than 10 µg/mL, indicating their strong radical scavenging capacity. We also report the crystal structures of compounds 1c, 1d, 1f, and 1g, which are found in monoclinic crystal systems.

Design, synthesis and mechanistic study of N-4-Piperazinyl Butyryl Thiazolidinedione derivatives of ciprofloxacin with Anticancer Activity via Topoisomerase I/II inhibition

A new group of thiazolidine-2,4-dione derivatives of ciprofloxacin having butyryl linker 3a-l was synthesized via an alkylation of thiazolidine-2,4-diones with butyryl ciprofloxacin with yield range 48–77% andfully characterized by various spectroscopic and analytical tools. Anti-cancer screening outcomes indicated that 3a and 3i possess antiproliferative activities against human melanoma LOX IMVI cancer cell line with IC50 values of 26.7 ± 1.50 and 25.4 ± 1.43 µM, respectively, using doxorubicin and cisplatin as positive controls with an IC50 of 7.03 ± 0.40 and 5.07 ± 0.29 µM, respectively. Additionally, compound 3j showed promising anticancer activity against human renal cancer A498 cell line with IC50 value of 33.9 ± 1.91 µM while doxorubicin and cisplatin showed IC50 values of 3.59 ± 0.20 and 7.92 ± 0.45, respectively. On the other hand, compound 3i did not show considerable anti-bacterial activity against S. aureus, E. coli and P. aeruginosa, and only moderate activity against K. pneumoniae with only a tenth of the activity of ciprofloxacin, confirming the cytotoxicity observed. Mechanistically, compound 3i inhibited both topoisomerase I and II with IC50 of 4.77 ± 0.26 and 15 ± 0.81 µM. Furthermore, it induced cell cycle arrest at S phase in melanoma LOX IMVI cells. Moreover, 3i provoked substantial levels of early, late apoptosis and necrosis in melanoma LOX IMVI cell line comparable to that induced by doxorubicin. Furthermore, compound 3i increased the expression level of active caspase-3 by 49 folds higher in LOX IMVI cell, increased protein expression level of Bax more than the control by 3 folds and inhibited PARP-1by 33% in LOX IMVI. All results were supported by theoretical docking studies on both tested enzymes confirming potential cytotoxicity for the synthesized hybrids.

One-pot synthesis of fused isoxazolo[4′,5′:4,5]thiopyrano[2,3-d]pyrimidines as potent EGFR targeting anti-lung cancer agents

The requirement for scaffolds has prompted synthetic chemists to devise simple and effective methods for optimal synthesis, which are critical in the medical industry. Under comparatively optimized conditions, a click followed by a CC bond coupling reaction between iodoalkyne (4) and substituted nitrile oxide was utilized to explore the synthesis of fused isoxazoles containing thiopyrano[2,3-d]pyrimidine under microwave irradiation. The synthesized compounds were tested for their anticancer activity against EGFR wild-type human non-small cell lung cancer cells (NCI-H460 and A549). The compounds 6i and 6l have shown more potent activity against both cancer cell lines as compared to standard drugs doxorubicin and erlotinib. And also compounds 6e, 6j, and 6k have shown more potent activity as compared to Doxorubicin and moderate activity compared to erlotinib. Later, in vitro EGFR results of more potent compounds revealed that compounds 6l and 6k have shown potent EGFR activity compared to standard erlotinib. To evaluate the molecular interactions of more potent compounds with the human epidermal growth factor receptor. It was observed that all the potent compounds exhibited greater binding energies in comparison to the standard drug erlotinib.

Design, Synthesis of Novel Pyrimidine Derivatives Containing Alkenyl Moieties With Herbicidal Activities

ABSTRACTTo identify lead compounds with potent herbicidal activity, a range of pyrimidine derivatives containing alkenyl groups were designed, synthesized, and characterized using nuclear magnetic resonance (NMR) spectroscopy and high‐resolution mass spectrometry (HRMS). The synthetic pathways for producing these compounds involved substitution reactions, cyclization, hydrolysis, and other processes. The starting materials for each reaction step were readily accessible, facilitating synthesis. The purification of the final product was straightforward, yielding approximately 80%, under mild reaction conditions. Moreover, a pot culture experiment was employed to assess the herbicidal efficacy of the aforementioned compounds. Compounds 6a, 6b, 6h, and 6j demonstrated a significant inhibition against Amaranthus retroflexus, comparable to fomesafen at 150 g a.i./hm2. This suggests that these compounds hold promise as potential lead structures for herbicidal agents. The docking results indicated that the binding energies of compound 6a with protoporphyrinogen oxidase (PPO) were both negative and spontaneous, with numerous interaction active sites. Thus, it is speculated that compound 6a is a PPO inhibitor.

Scaffold hopping approach to the novel hexacyclic pyrazol-3-amide derivatives as potential multi-target insect growth regulators candidates

Ecdysone receptor (EcR) and three insect chitinases (OfChtI, OfChtII, and OfChi-h) are considered as attractive targets for the development of novel insect growth regulators (IGRs) since they are closely related to the insect molting. In this study, to develop potent multi-target IGRs, a series of hexacyclic pyrazol-3-amide derivatives were rationally designed by utilizing the scaffold hopping strategy with the previously reported compound 6j (N-(4-bromobenzyl)-2-phenyl-4,5,6,7-tetrahydro-2H-indazole-5-carboxamide) as a lead compound. The bioassay results indicated that most of the target compounds exhibited obvious insecticidal activity. Especially, compounds a5 and a21 displayed excellent insecticidal activities against P. xylostella with LC50 values of 82.29 and 69.45 mg/L, respectively, exceeding that of 6j (263.78 mg/L). Compounds a5 and a21 also dramatically disturbed the growth and development of O. furnacalis larvae, and their LC50 values were 124.71 and 127.54 mg/L, respectively, superior to the lead 6j (267.33 mg/L). The action mechanism study revealed that the most active compound a21 could act simultaneously on EcR (21.4 % binding activity at 8 mg/L), OfChtI (94.9 % inhibitory at 10 μM), OfChtII (23.1 % inhibitory at 10 μM), and OfChi-h (94.3 % inhibitory at 10 μM), significantly higher than that of the lead compound 6j. The result of molecular docking indicated that transferring the carboxamide group from pyrazole position 5 to 3 enhanced the interactions of a21 with the key amino acid residues of the OfChtI, OfChtII, and OfChi-h, resulting in stronger affinity to the three targets than 6j. The present work offers a useful guidance for the further development of novel multi-target IGRs.

Synthesis, Molecular Docking Studies and Biological Evaluation of Thiazolyl Hydrazone Derivatives of Chromone-3-carbaldehyde as Potent Anti-Oxidant and Anti-Inflammatory Agents.

A series of 15 thiazolyl hydrazone derivatives of chromone-3- carbaldehyde have been designed and synthesized by the cyclization of thiosemicarbazone derivatives of chromone-3-carbaldehydes with 4'-substituted-2-bromo acetophenones. All these derivatives were evaluated for antioxidant activity by their direct scavenging activity objects to reactive oxygen species such as DPPH, and nitric oxide, as well as in vitro antiinflammatory activity by a protein denaturation method. Most of these synthesized compounds have shown significant antioxidant activity, among which the compounds 5b, 5c, 5e, 5g, and 5j showed very good antioxidant activities in comparison with the standard ascorbic acid. The in vitro anti-inflammatory activity revealed that the compounds 5b, 5g, and 5h possessed significant activity compared to standard diclofenac sodium. Additionally, molecular docking studies of these molecules using ovalbumin as the protein showed remarkable interactions with its active site residues, and the results indicated that the binding mode of these compounds closely resembled that of the reference compound, diclofenac sodium. Thus, these compounds represent an attractive template for the evaluation of new antiinflammatory and antioxidant agents and might be useful for exploring new therapeutic tools.

In vitro antiplasmodium and antitrypanosomal activities, β-haematin formation inhibition, molecular docking and DFT computational studies of quinoline-urea-benzothiazole hybrids

Quinoline-urea-benzothiazole hybrids exhibited low to sub-micromolar in vitro activities against the Plasmodium falciparum (P. falciparum) 3D7 chloroquine (CQ)-sensitive strain, with compounds 5a, 5b and 5f showing activities ranging from 0.33 to 0.97 μM. Against the formation of β-haematin, the majority of the tested compounds were comparable to the reference drug, chloroquine (CQ), with compounds 5c (IC50 = 9.55 ± 0.62 μM) and 5h (IC50 = 9.73 ± 1.38 μM), exhibiting slightly better in vitro efficacy than CQ. The hybrids also exhibited low micromolar to submicromolar activities against Trypanosoma brucei brucei, with 5j-5k being comparable to the reference drug, pentamidine. Compound 5b displayed higher in silico binding energy than CQ when docked against P. falciparum dihydroorotate dehydrogenase enzyme. Compounds 5j and 5k showed higher binding energies than pentamidine within the trypanothione reductase enzyme binding pocket. The root means square deviations of the hit compounds 5b, 5j and 5k were stable throughout the 100 ns simulation period. Post-molecular dynamics MMGBSA binding free energies showed that the selected hybrids bind spontaneously to the respective enzymes. The DFT investigation revealed that the compounds have regions that can bind to the electropositive and electronegative sites of the proteins.

Synthesis, spectroscopic characterization, DFT calculations, in silico-ADMET and molecular docking analysis of novel quinoline-substituted 5H-chromeno [2,3-b] pyridine derivatives as antibacterial agents.

A convenient, straightforward, and effective one-step reaction for the synthesis of a three-component compound of biologically relevant novel 2,4-diamino-5-(8-hydroxyquinolin-7-yl)-5H-chromeno[2,3-b] pyridine-3-carbonitrile derivatives was designed and synthesized. The synthesis was developed by the reaction between salicylaldehyde 1, 8-hydroxyquinoline 2, 2-aminopropene-1,1,3-tricarbonitrile 3, and the catalytic amount of triethylamine in ethanol at 78°C. This methodology has many beneficial features, including the use of inexpensive and non-hazardous starting materials, single-flask reactions, optimized reaction conditions, the termination of intermediate isolation, easy workup, reducing organic waste products, being chromatography-free, and decreasing the reaction time along with quantitative yields with high functional group tolerance. A proposed mechanism with supporting experimental data is presented, including 1H NMR, 13C NMR, 2D NMR (HMBC, COSY, HSQC), mass, and IR spectroscopy, which are used to characterize the complete derivatives. All synthesized compounds were evaluated in vitro for their antibacterial activities against Bacillussubtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacterial strains via the agar-well diffusion method compared with the reference drug gentamicin. The data indicated that compounds 4A, 4F, 4G, 4J, and 4K consistently demonstrated strong antimicrobial activity against Gram-positive and Gram-negative bacteria. Furthermore, a molecular docking investigation was carried out to gain insight into the binding mode of the most promising compounds via the crystal structure of the S. aureus DNA gyrase complex with ciprofloxacin (PDB ID: 2XCT). Density functional theory (DFT) calculations were performed to determine the various molecular properties of the synthesized novel 2,4-diamino-5-(8-hydroxyquinolin-7-yl)-5H-chromeno [2,3-b] pyridine-3-carbonitrile derivatives (4A-4M). On the basis of the reactive sites explored by the molecular electrostatic potential maps, the antibacterial activities of the compounds were screened.

Synthesis, antibacterial, anti-urease, DFT and molecular docking studies of novel bis-1,3,4-thiadiazoles

A series of 2-substitutedamino-1,3,4-thiadiazoles (4a-4j) were synthesized starting from various isothiocyanate derivatives. The newly synthesized compounds were characterized by 1H NMR, 13C NMR, and elemental analysis. All compounds were tested for antibacterial activity against Proteus vulgaris (ATCC 7829) via the microbroth dilution technique. Among them, compound 4h emerged as the most potent antibacterial agent with MIC value of 4.1 μM. All synthetic compounds were additionally evaluated for their urease inhibitory activity and exhibited good inhibitory potential against urease with IC50 values in the range of 1.732 ± 0.186 - 3.786 ± 0.300 μM as compared to the standard thiourea (IC50 = 11.008 ± 0.932 μM). Compounds 4d, 4h and 4i showed significant inhibitory effects with IC50 values of 1.981 ± 0.265, 1.732 ± 0.186 and 1.937 ± 0.173 μM, respectively. In silico molecular docking study showed the critical interactions of compound 4h with the active site of the urease. According to DFT, compounds 4j and 4d (with low ΔE=4.536 eV and 4.629 eV values, respectively) are more chemically reactive than the other molecules, in which consistent with their inhibitory potentials against the urease enzyme. Molecular Dynamics simulations also were performed to assess the energetic features of the urease in complex with compound 4h. Furthermore, the predicted ADMET characteristics of the compound 4h was calculated using QikProp to gain insights into its pharmacokinetic properties. These newly identified inhibitors of the urease enzyme can serve as leads for further antibacterial drug research and development.