Synthesis,modeling, and biological studies of new thiazole-pyrazole analogues as anticancer agents

A series of various substituted thiazole-pyrazole hybrids 5, 7, 8, and 9 were synthesized, and their chemical structures were confirmed by spectral data (infrared, ¹H & ¹³C NMR and Mass). The frontier molecular orbital structural and energetic properties of the targeting thiazole-pyrazole hybrids were explored using the DFT/B3LYP methodology. The data indicated that they had a low energy gap (ΔE_H-L), 1.51–2.42 eV, and may be sorted as 6 < 9 < 7 < 8 < 4 < 3 < 5. The synthesized thiazole-pyrazole hybrids were explored for their activities towards HepG2, MCF-7, and HCT-116 in contrast to doxorubicin. The newly synthesized thiazole-pyrazole analogues demonstrated an acceptable efficiency towards the HepG2 cancer cell line in accordance with this order: 8 > 9 > 7 > 6. Meanwhile, most of the synthesized analogues displayed a significant reduction for the activity of the CAIX inhibitor, with IC₅₀ = 0.071 ± 0.015 to 0.902 ± 0.043 µM. Likewise, they revealed an IC₅₀ = 0.119 ± 0.043 to 0.906 ± 0.04 µM for CAXII inhibitor. Moreover, the newly synthesized thiazole-pyrazole analogues were exposed to the theoretical molecular docking study with PDB:1RHJ as the crystal structure of caspase-3 to examine their antiapoptotic effect as well as their certain properties on the caspase-3 enzyme.     

Design,synthesis, biological evaluation and in silico studies of novel 1,2,3-triazole linked benzoxazine-2,4-dione conjugates as potent antimicrobial,antioxidant and anti-inflammatory agents

In an attempt to rationalize the search for new potential anti-inflammatory and anti-infection agents, a new series of 1,4-and 1,5-disubstituted 1,2,3-triazoles linked benzoxazine conjugates have been synthesized via “Click Chemistry” reaction, were designed, synthesized and characterized by means of spectral and elemental data. The newly synthesized compounds have been assessed for their antimicrobial, antioxidant and anti-inflammatory potential. Results revealed that all synthesized compounds display superior activities to the standard drug against different bacterial strains especially S. aureus, M. luteus, and P. aeruginosa, with good to moderate activity towards the tested E. coli bacteria, in respect to the commercial antibiotic, tetracycline. Moreover, the antifungal activity was screened against C. albicans and C. krusei yeasts and results demonstrate potent activity as compared to the standard drug, ampicillin. The antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assays, whose results indicate that analogues 4a (IC₅₀ 1.88 ± 0.07 µM and 2.17 ± 0.02) followed by 4b (IC₅₀ 2.19 ± 0.09 µM and 2.38 ± 0.43 µM), 4d (IC₅₀ 2.30 ± 0.01 µM and 4.07 ± 0.57 µM), and 4f (2.98 ± 0.02 µM and 3.80 ± 0.01 µM), respectively, exhibited the strongest activity when compared to the standard reference, butylated hydroxytoluene (BHT) (3.52 ± 0.08 µM and 4.64 ± 0.11 µM). In addition, their anti-inflammatory activity was assessed using the xylene-induced ear edema standard technique and the results demonstrated the potency of 4a, 4b and 4d as excellent anti-inflammatory agents. Preliminary structure–activity relationship studies (SARs) provide those biological activities can be modulated by the presence of unsubstituted aromatic ring as well as the position of substituents on the phenyl moiety via electron withdrawing groups (EWGs) or electron donating groups (EDGs) effects. Docking studies on the most promising compounds 4a, 4b, and 4d into the active sites of S. aureus tyrosyl-tRNA synthetase, Candida albicans N-Myristoyltransferase, Human COX-2 enzyme, and Human Peroxiredoxin 5 revealed good binding profiles with the target proteins. The interaction's stability was further assessed using a conventional atomistic 100 ns dynamic simulation study. Hence, our results recommended the rationalized targets 4a, 4b and 4d, to be promising lead candidates for the discovery of novel dual anti-inflammatory and anti-infection agents.     

Design,synthesis, docking and mechanistic studies of new thiazolyl/thiazolidinylpyrimidine-2,4-dione antiproliferative agents

In this article, we display on the synthesis and biological evaluation of a new series of thiazolylpyrimidine 3a-l and thiazolidinylpyrimidine derivatives 5a-e. The structures of the new compounds were confirmed by using different spectral techniques including NMR, IR, mass spectroscopy in addition to elemental analyses. The cell viability of the new compounds was assessed against normal human mammary gland epithelial (MCF-10A) cell line. Data revealed that none of the compounds examined exhibited cytotoxic effects, and the cell viability for the compounds examined at 50 µM was greater than 87%. The antiproliferative activity of 3a-l and 5a-e was evaluated against four human cancer cell lines where the compounds showed promising activity. The most potent derivatives were compounds 3a, 3c, 3f, 3i, and 5b with GI₅₀ values ranging from 0.90 µM to 1.70 µM against the four cancer cell lines in comparison to doxorubicin (GI₅₀ = 1.10 µM). Compounds 3a, 3c and 3i showed potent antiproliferative activity with dual inhibitory action against EGFR and BRAF^V600E. Compounds 3a, 3c, and 3i demonstrated promising AutoDock scores towards EGFR and BRAF^V600E with values of ? 9.1 and ? 8.6, ?9.0 and ? 8.5, and ? 8.4 and ? 8.0 kcal/mol, respectively. The physicochemical and pharmacokinetic characteristics of 3a, 3c, and 3i were anticipated, demonstrating their oral bioavailability.     

The design of fluoroquinolone-based cholinesterase inhibitors: Synthesis,biological evaluation and in silico docking studies

An enhanced acetylcholinesterase (AChE) activity is a hallmark in early stages of Alzheimer's ailment that results in decreased acetylcholine (ACh) levels, which in turn leads to cholinergic dysfunction and neurodegeneration. Consequently, inhibition of both AChE and butyrylcholinesterase (BChE) is important to prolong ACh activity in synapses for the enhanced cholinergic neurotransmission. In this study, a series of new fluoroquinolone derivatives (7a-m) have synthesized and evaluated for AChE and BChE inhibitory activities. The screening results suggested that 7 g bearing ortho fluorophenyl was the most active inhibitor against both AChE and BChE, exhibiting IC₅₀ values of 0.70 ± 0.10 µM and 2.20 ± 0.10 µM, respectively. The structure–activity relationship (SAR) revealed that compounds containing electronegative functions (F, Cl, OMe, N and O) at the ortho position of the phenyl group exhibited higher activities as compared to their meta- and/or para substituted counterparts. Molecular docking studies of synthesized compounds 7a, 7g, 7j and 7l docked into the active site of AChE and 7a-f docked into the active site of BChE revealed that these compounds exhibited conventional H-bonding along with π-π interaction with the active residues of AChE through their electronegative functions and phenyl ring, respectively. All the synthesized compounds are characterized by spectroscopic methods including FT-IR, ¹H- and ¹³C NMR as well as elemental analysis. This is the first example of fluoroquinolone-based cholinesterase inhibitors.     

Design and synthesis of 2,4-dioxochroman-pyridinium-phenylacetamide derivatives as new anti-Alzheimer agents: in vitro and in silico studies

2,4-Dioxochroman-pyridinium-phenylacetamide derivatives 7a–n were synthesized and evaluated for their in vitro cholinesterase (ChE) inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Obtained results demonstrated that, among the synthesized compounds, two compounds, 7j and 7k , were more potent than the standard drug donepezil against BuChE and did not show cytotoxicity and carcinogenicity. Furthermore, through molecular modeling and molecular dynamic studies. we showed that these compounds can be located deep in the gorge cavity of BuChE and that they interacted with catalytic residues, acyl, and cholin-binding pockets of this enzyme. Support information     

Synthesis,biological evaluation,quantitative-SAR and docking studies of novel chalcone derivatives as antibacterial and antioxidant agents

In the present study, a series of chalcone derivatives including 17 new compounds were synthesised; their antibacterial activities against eleven bacteria, and their free radical-scavenging activities using DPPH were evaluated. All compounds showed significant antibacterial activities against both Gram-positive and Gram-negative bacteria. In particular, compound IIIf strongly inhibited Staphylococcus aureus (JMC 2151) and Enterococcus faecalis (CARS 2011-012) with MIC values of 6.25 µg mL^?1 and 12.5 µg mL^?1, respectively, which are comparable to that of the standard antibiotic, nalidixic acid. Compound IIIg also inhibited S. aureus with a MIC value similar to that of nalidixic acid (6.25 µg mL^?1). Furthermore, like nalidixic acid (MIC value of 25 µg mL^?1), compounds IIIa, IIIc and IIId inhibited Listeria monocytogenes (ATCC 43256) with MIC values of 25 µg mL^?1, 12.5 µg mL^?1 and 25 µg mL^?1, respectively. Quantitative structure-activity relationship (Q-SAR) studies using physicochemical calculations indicated that the antibacterial activities of chalcone derivatives correlated well with predicted physicochemical parameters (logP and PSA). Docking simulation by positioning the most active compound IIIf in the active site of the penicillin-binding protein (PBP-1b) of S. aureus was performed to explore the feasible binding mode. Furthermore, most of the compounds synthesised exhibited significant DPPH radical-scavenging activity, although compounds IIc and IIIc exhibited the greatest antioxidant activity with IC₅₀ values of 1.68 µM and 1.44 µM, respectively, comparable to that of the standard antioxidant, ascorbic acid (1.03 µM).     

Synthesis,biological evaluation,and molecular docking studies of novel 1,2,3-triazole derivatives as potent anti-inflammatory agents

In the present study, a novel series of 1,2,3-triazole derivatives have been synthesized using click chemistry approach. The structures were confirmed by spectroscopic methods. The products were screened for their in vivo anti-inflammatory activity. The tested compounds 6a, 6f, 6g, 6i, 6j, 6n, and 6p, demonstrated potent anti-inflammatory activity compared to the reference drug ibuprofen. Molecular docking studies of these 1,2,3-triazole derivatives into the active site of human cyclooxygenase-2 (COX-2) (PDB code 4PH9) demonstrated good affinity for the enzyme and suggested binding properties similar to ibuprofen.     

Novel imidazole derivatives as antifungal agents: Synthesis,biological evaluation,ADME prediction and molecular docking studies

Abstract

A series of 2-(substituteddithiocarbamoyl)-N-[4-((1H-imidazol-1-yl)methyl)phenyl]acetamide derivatives was designed and synthesized to combat the increasing incidence of drug-resistant fungal infections. All synthesized compounds were characterized by IR, ¹H-NMR, ¹³C-NMR, and HRMS spectra and elemental analyses. Antifungal activity tests were performed against four different fungal strains. Molecular docking studies were performed to investigate the mode of action towards the fungal lanosterol 14α-demethylase, a cytochrome P450-dependent enzyme. ADME studies were carried out and a connection between activities and physicochemical properties of the target compounds was determined. Most of the final compounds exhibited significant activity against Candida albicans and Candida krusei with MIC₅₀ value 12.5?μg/mL. The results of in vitro anti-Candida activity, a docking study and ADME prediction revealed that the newly synthesized compounds have potential anti-Candida activity and evidenced the most active derivative, 5b (2-Pyrrolidinthiocarbonylthio-N-[4-((1H-imidazol-1-yl)methyl)phenyl]acetamide), which can be further optimized as a lead compound.     

Synthesis,biological evaluation,and molecular docking studies of novel pyrazole,pyrazoline-clubbed pyridine as potential antimicrobial agents

We have prepared 15 hybrid pyrazole, pyrazoline-clubbed pyridine–containing compounds (5a-o) and tested for their antibacterial and antifungal activities for the development of potential antimicrobial agents. The structures of this novel series were characterized by various spectral techniques like IR, ¹H NMR, ¹³C NMR, LC–MS, and elemental analysis. The synthesized compounds 5d, 5e, 5i, 5k, 5m, and 5o exhibited significant antimicrobial activity in the comparison of standard drugs. Molecular docking studies that have been carried out to emphasize the binding orientations of these molecules were in good compliance with crystal structure interactions. The predicted drug-likeness (ADME) properties were found to be in the acceptable range.     

Synthesis,biological evaluation,and molecular docking studies of diacylhydrazine derivatives possessing 1,4-benzodioxan moiety as potential anticancer agents

Russian Journal of General Chemistry - A series of diacylhydrazine derivatives containing 1,4-benzodioxan 1-17 has been designed, synthesized and evaluated for antitumor activity. Most of the...     

Synthesis,biological evaluation and molecular docking study of dihydropyrimidine derivatives as potential anticancer agents

A series of dihydropyrimidine analogues were prepared via one-pot Biginelli three-component condensation reaction and characterized by NMR, FT-IR, MS spectra, and element analysis. Subsequently, they were screened for in vitro anticancer effect. These analogues revealed good cytotoxic activity against three human cancer cell lines including MCF-7, HepG-2, and A549. Among these analogues, compounds 4d and 4h were the most potent against three cell lines. Cell viability assays indicated 4a and 4c had lower cytotoxicity. In vitro cytotoxicity study on all synthesized compounds demonstrated that introduction of electron withdrawing substituents on C4 position of phenyl ring of dihydropyrimidine contributed to the antiproliferative potency. Moreover, in silico molecular docking results stipulated a sign of good correlation between experimental activity and calculated binding affinity. It proved 4d and 4h as the strongest compounds. Binding modes of analogues proposed the involvement of hydrophobic interactions and hydrogen bonds with Eg5 active site. Structure activity relationship studies indicated that incorporating electron withdrawing substituents on C4 position of phenyl ring of dihydropyrimidine are important for this biological activity.     

Design,synthesis and biological evaluation of new rhodacyanine analogues as potential antitumor agents

In an attempt to develop potent antitumor agents,new rhodacyanine analogues containing the pyridinium ring（5a-5h）,the isoquinolinium ring（6a-6c） and the quinolinium ring（7a-7e） linked to the rhodanine ring via N-N covalent bond were designed, synthesized and evaluated for antitumor activity against human lung cancer cell line（H460） by MTT assay in vitro.Most of the tested compounds showed enhanced antitumor activity with IC₅₀ values ranging from 0.006 to 9.2 u,mol/L as compared to the lead compound MKT-077.Among them,the most promising compound 7d(IC₅₀ = 0.006μmol/L) was 216.7 times more active than MKT-077(IC₅₀ = 1.3μmol/L).The preliminary structure-activity relationship of the target compounds was discussed.     

Synthesis,biological evaluation and molecular docking studies of novel benzimidazole derivatives

A novel series of N-substituted-benzimidazolyl linked para substituted benzylidene based molecules containing three pharmacologically potent hydrogen bonding parts namely; 2,4-thiazolidinedione (TZD: a 2,4-dicarbonyl), diethyl malonate (DEM: a 1,3-diester and an isooxazolidinedione analog) and methyl acetoacetate (MAA: a β-ketoester) (6a–11b) were synthesized and evaluated for in vitro α-glucosidase inhibition. The structure of the novel synthesized compounds was confirmed through the spectral studies (LC–MS, ¹H NMR, ¹³C NMR, FT-IR). Comparative evaluation of these compounds revealed that the compound 9b showed maximum inhibitory potential against α-amylase and α-glucosidase giving an IC₅₀ value of 0.54 ± 0.01 μM. Furthermore, binding affinities in terms of G score values and hydrogen bond interactions between all the synthesized compounds and the AA residues in the active site of the protein (PDB code: 3TOP) to that of Acarbose (standard drug) were explored with the help of molecular docking studies. Compound 9b was considered as promising candidate of this series.     

Synthesis and biological evaluation of new ligustrazine derivatives as anti-tumor agents

To discover new anti-cancer agents with multi-effect and low toxicity, a series of ligustrazine derivatives were synthesized using several effective anti-tumor ingredients of Shiquandabu Wan as starting materials. Our idea was enlightened by the "combination principle" in drug discovery. The ligustrazine derivatives' anti-tumor activities were evaluated on the HCT-8, Bel-7402, BGC-823, A-549 and A2780 human cancer cell lines. In addition the angiogenesis activities were valued by the chick chorioallantoic membrane (CAM) assay. 1,7-bis(4-(3,5,6-Trimethylpyrazin-2-yl)-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (4) and 3 α,12 α-dihydroxy-5β-dholanic acid-3,5,6-trimethylpyrazin-2-methyl ester (5) not only displayed antiproliferative activities on these cancer cells, but also dramatically suppressed normal angiogenesis in CAM. The LD?? value of the compound 5 exceeded 3.0 g/kg by oral administration in mice.     

Novel 2,4-disubstituted quinazolines as cytotoxic agents and JAK2 inhibitors: Synthesis,in vitro evaluation and molecular dynamics studies

Recent studies reported the involvement of JAK2/STAT3 pathway in various solid tumours including breast, ovarian, prostate and lung cancers. Clinical literature also reported the lowered burden in breast and ovarian cancers by targeting JAK2 pathway. In this study, a series of novel 2,4-disubstituted quinazolines (2a-2 j and 3a-3 j) were synthesized and were evaluated for their cytotoxicity against human breast cancer (MDA-MB-231) and ovarian cancer (SK-O-V3) cell lines using MTT assay. Moderate to good in vitro cytotoxic potentials of the newly synthesized molecules were reported against selected human cancer cell lines. Among the tested molecules, compound 3b has shown better cytotoxic activity against MD-MB-231 (10.1 ± 0.51 μM). in vitro JAK2 inhibition assay elucidated the mechanistic profile of the derivatives with moderate percentage of inhibition. Compounds 3b and 3d were reported with 35.4% and 34.2% inhibition of JAK2 protein. SAR studies suggest that the larger hydrophobic aromatic nucleus with hydrophilic linkage could probably increase the cytotoxic and JAK2 potentials and hydroxyl or nitro substitution could be more beneficial. Molecular dynamics simulation studies with JAK2-3b, and JAK2-3d complexes elucidated the conformational changes. With the reported bioactivities of these derivatives, further studies on the derivatization could elucidate the broader cytotoxic potentials.     

Synthesis,characterization, molecular docking studies and in vitro screening of new metal complexes with Schiff base as antimicrobial and antiproliferative agents

A series of Cu(II), Co(II), Pd(II), Pt(II), Zn(II), Cd(II) and Fe(III) complexes were designed and synthesized using Schiff base 1‐phenyl‐2,3‐dimethyl‐4‐(N‐3‐formyl‐6‐methylchromone)‐3‐pyrazolin‐5‐one (HL). The new metal complexes were investigated using various physicochemical techniques including elemental and thermal analyses, molar electric conductivity and magnetic susceptibility measurements, as well as spectroscopic methods. Also, the crystal structures of ligand HL and the Pd(II) complex were determined using single‐crystal X‐ray diffraction analysis. For all compounds, the antimicrobial activity was studied against a series of standard strains: Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, Escherichia coli, Acinetobacter baumannii, Candida albicans, Candida krusei and Cryptococcus neoformans. The in vitro antiproliferative activity of the ligand and complexes was evaluated against ten cancer cell lines: MSC, A375, B16 4A5, HT‐29, MCF‐7, HEp‐2, BxPC‐3, RD, MDCK and L20B. At 10 μM concentration a significant cytotoxic effect of the Co(II), Pd(II) and Cd(II) complexes was observed against B16 4A5 murine melanoma cells. The Zn(II) complex is active against HEp‐2, RD and MDCK cancer cell lines, where IC₅₀ values vary between 1.0 and 77.6 and for BxPC‐3 the activity index versus doxorubicin is 3.7 times higher.     

Identification of some chalcone analogues as potential antileishmanial agents: An integrated in vitro and in silico evaluation

Chalcones, either natural or synthetic, are known to exhibit various biological activities. The present study aimed to evaluate the in vitro and in silico activities of some chalcone analogues as potential antleishmanial agents via inhibition of the trypanothione reductase enzyme (TR). Five chalcone analogues were synthesized using Claisen-Schmidt reaction and their activity has been evaluated against Leishmania donovani and presented as IC₅₀ values. Various integrated web-based technologies were used to assess the synthesized compounds' absorption, distribution, metabolism, excretion, and toxicity profile (ADMET). The binding affinity of the most potent chalcone for the selected target was then investigated using Auto-Dock 4.0. Additionally, the molecular dynamics was performed using WEBGRO. (E)-1-(4-bromophenyl)-3-(4-hydroxyphenyl) prop-2-en-1-one (Chalcone 4) has shown the highest inhibitory effect with IC₅₀ value 0.03 ± 0.16 µM. In addition, the pharmacokinetic and toxicological investigations revealed its good oral bioavailability and low toxicity. Furthermore, chalcone 4 was found to interact with high affinity (?8.6 kcal/mole) with trypanothione reductase (TR), an essential enzyme for the leishmanial parasite. Molecular dynamics simulation revealed several interesting features responsible for the potency and stability of chalcone 4 as TR inhibitor. Thus, the promising activity against Leishmania donovani, compared to amphotericin B and other reported chalcones derivatives, proposes the use of chalcone 4 as a potential new therapy for visceral leishmaniasis.     

New quinoxaline-piperazine-oxazole conjugates: Synthesis,in vitro anticancer,in silico ADMET,and molecular docking studies

In this paper, we describe the synthesis of some new quinoxaline-piperazine-oxazole amide conjugates 6a-n from 3-chloroquinoxaline-2-carbonitrile using well-known reaction sequences. The synthesized compounds were characterized by ¹H NMR,¹³C NMR, and mass spectral analysis. The compounds were tested for their in vitro antiproliferative activity toward four different cancer cell lines such as PC-3, MCF-7, DU-145, and A-549 by MTT method. The compounds, 6c, 6h, 6i , and 6n were found to be more potent than the standard Erlotinib. In vitro tyrosine kinase EGFR inhibition studies using four potent compounds revealed that 6n has double inhibiting tendency with value IC₅₀ of 0.22 μM and 6h with value of IC₅₀ 0.27 μM compared to reference compound. Molecular docking studies of active compounds, 6c , 6h , 6i , and 6n on EGFR receptor suggested that all the compounds have more binding energies than that of Erlotinib. Furthermore, the in silico pharmacokinetic profile was accomplished for the active compounds, 6c , 6h , 6i , and 6n using SWISS/ADME and pk CSM, whereas compounds, 6h , 6i , and 6c followed Lipinski rule, Veber rule, Egan rule and Muegge rule. The remaining compound 6n did not follow Lipinski rule, Ghose rule because one common violation, that is, because of high molecular weight (MW > 350).     

Palladium(II) complexes of 5-substituted isatin thiosemicarbazones: Synthesis,spectroscopic characterization,biological evaluation and in silico docking studies

Substituted heterocyclic (isatin) appended thiosemicarbazone ligands (L1–L3) are synthesized by condensation of substituted isatin molecule with N(4)-phenyl-3-thiosemicarbazide in good yields. The palladium(II) complexes are synthesized from ligands (L1–L3) and PdCl₂, with a general formula [PdCl(X-C₁₅H₁₀N₄OS)] where X?=?5-chloro (1), 5-bromo (2), and 5-nitro (3). Both analytical and spectroscopic methods have been used for the analysis and characterization of the synthesized compounds. The antimicrobial activity results observed that complexes, 1 and 2 have registered potent antibacterial activity against B. subtilis and K. pneumoniae and also complex 2 has shown good antifungal activity against the micro organisms. The antioxidant activity analysis revealed that the complex 3 showed significant activity with IC₅₀ values 7.24?±?0.09?µM. Moreover, the in vitro antiproliferative activity results suggested that complex 3 exhibited high activity against HeLa cell line compared with the standard with the IC₅₀ value 16.52?±?1.08?µM. The docking results correlate well.