Convenient Synthesis and Anticancer Activity of Methyl 2-[3-(3-Phenyl-quinoxalin-2-ylsulfanyl)propanamido]alkanoates and N-Alkyl 3-((3-Phenyl-quinoxalin-2-yl)sulfanyl)propanamides

Benzylic C-H Oxidation: Recent Advances and Applications in Heterocyclic Synthesis

Benzylic C-H oxidation to form carbonyl compounds, such as ketones, is a fundamental transformation in organic synthesis as it allows for the preparation of versatile intermediates. In this review, we highlight the synthesis of aromatic ketones via catalytic, electrochemical, and photochemical oxidation of alkylarenes using different catalysts and oxidants in the past 5 years. Additionally, we also discuss the synthesis of heterocyclic molecules using benzylic C-H oxidation as a key step. These methods can potentially be used in medicinal, synthetic, and inorganic chemistry.

Synthesis and antiproliferative activity of 2-oxo-3-phenylquinoxaline derivatives and related compounds against colon cancer

We have designed 17 new 2-oxo-3-phenylquinoxalines via the chemoselective Michael reaction of 3-phenylquinoxalin-2(1H)-one with acrylic acid derivatives. The ester, ethyl 3-(2-oxo-3-phenylquinoxalin-1(2H)-yl)propanoate, was reacted with hydroxylamine and hydrazine to produce N-hydroxy-3-(2-oxo-3-phenylquinoxalin-1(2H)-yl)propanamide and hydrazide, respectively. Further modifications were made through reactions with isothiocyanates and azide coupling with amines, yielding thiosemicarbazides and N-alkyl derivatives. Molecular docking studies identified compound 7j as the most potent binder, fitting well into the active site, with the phenyl ring occupying the S1 pocket and the amino acid chain positioned in the S2 pocket. The synthesized compounds (2a, 4, 7a, 7g, 7d, 7h, 7e, 7b, 7c, 7f, and 7j) were evaluated for their anti-cancer activity on colorectal cancer (HCT-116) cells. Compounds 2a and 7j showed significant reductions in cell viability, with IC50 values of 28.85 ± 3.26 μg mL-1 and 26.75 ± 3.50 μg mL-1, respectively. Image analysis of HCT-116 cells treated with 60 μg mL-1 of compound 7j for 48 hours revealed notable morphological changes in both nuclei and cells. The number of cells reduced from 447 in the control to 238 in the treated group, with a corresponding reduction in the area covered by cells from 41.9% to 17.6%. Nuclear disintegration and chromatin fragmentation were observed, confirming apoptosis. These results highlight the potent cytotoxic effect of compound 7j.

Robust aptamer-targeted CRISPR/Cas9 delivery using mesenchymal stem cell membrane -liposome hybrid: BIRC5 gene knockout against melanoma

In this study, a platform was fabricated by combining a cationic lipid, 1,2-Dioleoyl-3-trimethylammonium-propane (DOTAP) with mesenchymal stem cell membrane (MSCM) to produce a positively charged hybrid vesicle. The prepared hybrid vesicle was used to condense BIRC5 CRISPR/Cas9 plasmid for survivin (BIRC5) gene editing. The Sgc8-c aptamer (against protein tyrosine kinase 7) was then attached to the surface of the prepared NPs through electrostatic interactions. In this regard, melanoma cancer cells (B16F0 cell line) overexpressing PTK7 receptor could be targeted. Investigations were conducted on this system to evaluate its transfection efficiency, cellular toxicity, and therapeutic performance in preclinical stage using B16F0 tumor bearing C57BL/6 J mice. The results verified the superiority of the Hybrid/ BIRC5 compared to Liposome/ BIRC5 in terms of cellular toxicity and transfection efficiency. The cells exposure to Hybrid/BIRC5 significantly enhanced cytotoxicity. Moreover, Apt-Hybrid/BIRC5 showed higher anti-proliferation activity toward PTK7-positive B16F0 cancer cells than that of the PKT7-negative CHO cell line. The active tumor targeting nanoparticles increased the cytotoxicity through down-regulation of BIRC5 expression as confirmed by Western blot analysis. In preclinical stage, Apt-Hybrid/BIRC5 showed remarkable tumor growth suppression toward B16F0 tumorized mice. Thus, our study suggested that genome editing for BIRC5 through the CRISPR/Cas9 system could provide a potentially safe approach for melanoma cancer therapy and has great potential for clinical translation.

Recent advances on quinoxalines as target-oriented chemotherapeutic anticancer agents through apoptosis

The current review outlines all possible recent synthetic platforms to quinoxaline derivatives and the potent stimulated apoptosis mechanisms targeted by anticancer therapies. The currently reported results disclosed that quinoxaline derivatives had promising anticancer potencies against a wide array of cancer cell lines, better than the reference drugs, through target inhibition. This review summarizes some potent quinoxaline derivatives with their synthesis strategies and their potential activities against various molecular targets. Quinoxalines can be considered an important scaffold for apoptosis inducers in cancer cells through inhibiting some molecular targets, so they can be further developed as target-oriented chemotherapeutics.

Design and Synthesis of Quinoxaline Hybrids as Modulators of HIF-1a, VEGF, and p21 for Halting Colorectal Cancer

A library of 16 3-benzyl-N 1-substituted quinoxalin-2-ones was synthesized as N 1-substituted quinoxalines and quinoxaline-triazole hybrids via click reaction. These compounds were tested for their anticancer activity via MTT assay on HCT-116 and normal colonocyte cell lines to assess their cytotoxic potentials and safety profiles. Overall, compounds 6, 9, 14, and 20 were found to be promising anticolorectal cancer agents; they exhibited remarkable cytotoxicity (IC50 0.05-0.07 μM) against HCT-116 cells within their safe doses (EC100) on normal colon cells. Their pronounced anticancer activities were observed as severe morphological alterations and shrinkage of the treated cancer cells. Besides, qRT-PCR analysis was conducted showing the potential of the promising hits to downregulate HIF-1a, VEGF, and BCL-2 as well as their ability to enhance the expression of proapoptotic genes p21, p53, and BAX in HCT-116 cells. In silico prediction revealed that most of our compounds agree with Lipinski and Veber parameters of rules, in addition to remarkable medicinal chemistry and drug-likeness parameters with no CNS side effects. Interestingly, docking studies of the compounds in the VEGFR-2' active site showed significant affinity toward the essential amino acids, which supported the biological results.

Quinoxaline derivatives: Recent discoveries and development strategies towards anticancer agents

Cancer is a leading cause of death and a major health problem worldwide. While many effective anticancer agents are available, most drugs currently on the market are not specific, raising issues like the common side effects of chemotherapy. However, recent research hold promises for the development of more efficient and safer anticancer drugs. Quinoxaline and its derivatives are becoming recognized as a novel class of chemotherapeutic agents with activity against different tumors. The present review compiles and discusses studies concerning the therapeutic potential of the anticancer activity of quinoxaline derivatives, covering articles published between January 2018 and January 2023.

Recent Methods for the Synthesis of Quinoxaline Derivatives and their Biological Activities

Quinoxaline derivatives have been incorporated into numerous marketed drugs used for the treatment of various diseases. Examples include glecaprevir (Mavyret), voxilaprevir (Vosevi), Balversa (L01EX16) (erdafitinib), carbadox, XK469R (NSC698215), and becampanel (AMP397). These quinoxaline derivatives exhibit a diverse range of pharmacological activities, including antibacterial, antitubercular, antiviral, anti-HIV, anti-inflammatory, antifungal, anticancer, antiproliferative, antitumor, kinase inhibition, antimicrobial, antioxidant, and analgesic effects. Recognizing the significance of these bioactive quinoxaline derivatives, researchers have dedicated their efforts to developing various synthetic methods for their production. This review aimed to compile the most recent findings on the synthesis and biological properties of quinoxaline derivatives from 2015 to 2023.

Anticancer Activity of Au/CNT Nanocomposite Fabricated by Nanosecond Pulsed Laser Ablation Method on Colon and Cervical Cancer

Gold nanoparticles (AuNPs) and carbon nanotubes (CNTs) are increasingly being investigated for cancer management due to their physicochemical properties, low toxicity, and biocompatibility. This study used an eco-friendly technique (laser synthesis) to fabricate AuNP and Au/CNT nanocomposites. AuNPs, Au/CNTs, and CNTs were tested as potential cancer nanotherapeutics on colorectal carcinoma cells (HCT-116) and cervical cancer cells (HeLa) using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. In addition, the non-cancer embryonic kidney cells HEK-293 were taken as a control in the study. The cell viability assay demonstrated a significant reduction in cancer cell population post 48 h treatments of AuNPs, and Au/CNTs. The average cell viabilities of AuNPs, Au/CNTs, and CNTs for HCT-116 cells were 50.62%, 65.88%, 93.55%, and for HeLa cells, the cell viabilities were 50.88%, 66.51%, 91.73%. The cell viabilities for HEK-293 were 50.44%, 65.80%, 93.20%. Both AuNPs and Au/CNTs showed higher cell toxicity and cell death compared with CNT nanomaterials. The treatment of AuNPs and Au/CNTs showed strong inhibitory action on HCT-116 and HeLa cells. However, the treatment of CNTs did not significantly decrease HCT-116 and HeLa cells, and there was only a minor decrease. The treatment of AuNPs, and Au/CNTs, on normal HEK-293 cells also showed a significant decrease in cell viability, but the treatment of CNTs did not produce a significant decrease in the HEK-293 cells. This study shows that a simplified synthesis technique like laser synthesis for the preparation of high-purity nanomaterials has good efficacy for possible future cancer therapy with minimal toxicity.

Comparative Anticancer Potentials of Taxifolin and Quercetin Methylated Derivatives against HCT-116 Cell Lines: Effects of O-Methylation on Taxifolin and Quercetin as Preliminary Natural Leads

Six flavonoids present in Pulicaria jaubertii, i.e., 7,3'-di-O-methyltaxifolin (1), 3'-O-methyltaxifolin (2), 7-O-methyltaxifolin (3), taxifolin (4), 3-O-methylquercetin (5), and quercetin (6), were tested for their anticancer activities. The methylated flavonoids, compounds 1-3 and 5, were evaluated for their anticancer activities in comparison to the non-methylated parent flavonoids taxifolin (4) and quercetin (6). The structures of the known compounds were reconfirmed by spectral analyses using ¹H and ¹³C NMR data comparisons and HRMS spectrometry. The anticancer activity of these compounds was evaluated in colon cancer, HCT-116, and noncancerous, HEK-293, cell lines using the MTT antiproliferative assays. The caspase-3 and caspase-9 expressions and DAPI (4', 6-diamidino-2-phenylindole) staining assays were used to evaluate the apoptotic activity. All the compounds exhibited antiproliferative activity against the HCT-116 cell line with IC₅₀ values at 33 ± 1.25, 36 ± 2.25, 34 ± 2.15, 32 ± 2.35, 34 ± 2.65, and 36 ± 1.95 μg/mL for compounds 1 to 6, respectively. All the compounds produced a significant reduction in HCT-116 cell line proliferation, except compounds 2 and 6. The viability of the HEK-293 normal cells was found to be significantly higher than the viability of the cancerous cells at all of the tested concentrations, thus suggesting that all the compounds have better inhibitory activity on the cancer cell line. Apoptotic features such as chromatin condensation and nuclear shrinkage were also induced by the compounds. The expression of caspase-3 and caspase-9 genes increased in HCT-116 cell lines after 48 h of treatment, suggesting cell death by the apoptotic pathways. The molecular docking studies showed favorable binding affinity against different pro- and antiapoptotic proteins by these compounds. The docking scores were minimum as compared to the caspase-9, caspase-3, Bcl-xl, and JAK2.

Transformation of Amides to Thioamides Using an Efficient and Novel Thiating Reagent

A convenient protocol was developed for the transformation of N-aryl-substituted benzamides to N-aryl-substituted benzothioamides using N-isopropyldithiocarbamate isopropyl ammonium salt as a novel thiating reagent. The major advantages of this protocol are its one-pot procedure, short reaction times, mild conditions, simple work-up, high yields and pure products.

Convenient Synthesis of N-Alkyl-2-(3-phenyl-quinoxalin-2-ylsulfanyl)acetamides and Methyl-2-[2-(3-phenyl-quinoxalin-2-ylsulfanyl)acetylamino]alkanoates

A series of 27 new quinoxaline derivatives (N-alkyl-[2-(3-phenyl-quinoxalin-2-ylsulfanyl)]acetamides, methyl-2-[2-(3-phenylquinoxalin-2-ylsulfanyl)-acetylamino]alkanoates, and their corresponding dipeptides) were prepared from 3-phenylquinoxaline-2(1H)-thione based on the chemoselective reaction with soft electrophiles. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to study the efficacy of 27 compounds on cancer cell viability and proliferation. A total of 13 compounds (4a-c, 5, 6, 8c, 9c, 9f, 10a, 10b, 11c, 12b, and 12c) showed inhibitory action on HCT-116 cancer cells and 15 compounds (4a-c, 5, 6, 8c, 9a, 9c, 9f, 9h, 10b, 11c, 12a, 12b, and 12c) showed activity on MCF-7 cancer cells, with compound 10b exhibiting the highest inhibitory action (IC₅₀ 1.52 and 2 μg/mL, respectively) on both cell lines. The molecular modeling studies on the human thymidylate synthase (hTS) homodimer interface showed that these compounds are good binders and could selectively inhibit the enzyme by stabilizing its inactive conformation. The study also identified key residues for homodimer binding, which could be used for further optimization and development.

Synthesis of M-Ag3PO4, (M = Se, Ag, Ta) Nanoparticles and Their Antibacterial and Cytotoxicity Study

Silver Phosphate, Ag3PO4, being a highly capable clinical molecule, an ultrasonic method was employed to synthesize the M-Ag3PO4, (M = Se, Ag, Ta) nanoparticles which were evaluated for antibacterial and cytotoxicity activities post-characterization. Escherichia coli and Staphylococcus aureus were used for antibacterial testing and the effects of sonication on bacterial growth with sub-MIC values of M-Ag3PO4 nanoparticles were examined. The effect of M-Ag3PO4 nanoparticles on human colorectal carcinoma cells (HCT-116) and human cervical carcinoma cells (HeLa cells) was examined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay and DAPI (4′,6-diamidino-2-phenylindole) staining. Additionally, we analyzed the effect of nanoparticles on normal and non-cancerous human embryonic kidney cells (HEK-293). Ag-Ag3PO4 exhibited enhanced antibacterial activity followed by Ta-Ag3PO4, Ag3PO4, and Se-Ag3PO4 nanoparticles against E. coli. Whereas the order of antibacterial activity against Staphylococcus aureus was Ag3PO4 > Ag-Ag3PO4 > Ta-Ag3PO4 > Se-Ag3PO4, respectively. Percentage inhibition of E. coli was 98.27, 74.38, 100, and 94.2%, while percentage inhibition of S. aureus was 25.53, 80.28, 99.36, and 20.22% after treatment with Ag3PO4, Se-Ag3PO4, Ag-Ag3PO4, and Ta-Ag3PO4, respectively. The MTT assay shows a significant decline in the cell viability after treating with M-Ag3PO4 nanoparticles. The IC50 values for Ag3PO4, Se-Ag3PO4, Ag-Ag3PO4, and Ta-Ag3PO4 on HCT-116 were 39.44, 28.33, 60.24, 58.34 µg/mL; whereas for HeLa cells, they were 65.25, 61.27, 75.52, 72.82 µg/mL, respectively. M-Ag3PO4 nanoparticles did not inhibit HEK-293 cells. Apoptotic assay revealed that the numbers of DAPI stained cells were significantly lower in the M-Ag3PO4-treated cells versus control.

Base-catalyzed multicomponent access to quinoxalin-2-thiones from o-phenylenediamines, aryl ketones and sulfur

3-Arylquinoxaline-2-thiones were conveniently synthesized via three-component oxidative condensation of acetophenones with o-phenylenediamines and sulfur in DMSO in the presence of piperidine as a catalyst. The products could be readily isolated from the reaction mixture by simple precipitation and washing with methanol. This set of reaction conditions applied to higher homologs of acetophenones as well as benzyl phenyl ketones led to 2,3-di-C-substituted quinoxalines. Further functionalization of 3-phenylquinoxaline-2-thione via reaction on the thione group could be readily performed to provide quinoxaline derivatives in good yields.

Synthesis of Novel Phthalazinedione-Based Derivatives with Promising Cytotoxic, Anti-bacterial, and Molecular Docking Studies as VEGFR2 Inhibitors

The parent ester methyl-3-[2-(4-oxo-3-phenyl-3,4-dihydro-phthalazin-1-yloxy)-acetylamino] has 18 compounds. The starting material for alkanoates, their corresponding hydrazides, hydrazones, and dipeptides were produced by chemoselective O-alkylation of 2-phenyl-2,3-dihydrophthalazine-1,4-dione with ethyl chloroacetate(4-oxo-3-phenyl-3,4-dihydro-phthalazin-1-yloxy) acetic acid methyl ester. The starting ester was hydrazinolyzed, then azide coupled with amino acid ester hydrochloride to produce several parent esters, and then hydrazinolyzed to produce parent hydrazides. These hydrazides were used to make a series of dipeptides by reacting them with amino acid ester hydrochloride under azide coupling conditions, and they were also condensed with a number of aldehydes to make the hydrazones. These derivatives were subjected to cytotoxicity against HCT-116 and MDA-MB-231 cells and anti-bacterial and molecular docking studies. Results indicated that the tested compounds, especially 7c and 8b with the phenyl phthalazinone moieties, had promising cytotoxicity against the HCT-116 cells with IC₅₀ values of 1.36 and 2.34 μM, respectively. Additionally, the promising compounds 7c and 8b exhibited poor cytotoxicity against WISH cells with much higher IC₅₀ values, so they were safe against normal cells. Compound 8c exhibited potent anti-bacterial activity with inhibition zones of 12 and 11 mm against Staphylococcus aureus and Escherichia coli, respectively. The molecular docking results of compounds 7c and 8b revealed a good binding disposition and the ligand-receptor interactions like the co-crystallized ligand of the VEGFR2 protein, which may be the proposed mode of action. Finally, compounds 7c and 8b exhibited good ADME pharmacokinetics with good drug-likeness parameters. Hence, detailed studies for the mechanism of action of such compounds are highly recommended for the development of new potent anti-cancer and anti-bacterial agents.

Synthesis, DFT Molecular Geometry and Anticancer Activity of Symmetrical 2,2'-(2-Oxo-1H-benzo[d]imidazole-1,3(2H)-diyl) Diacetate and Its Arylideneacetohydrazide Derivatives

To identify new candidate anticancer compounds, we here report the synthesis of benzimidazole derivatives: diethyl 2,2'-(2-oxo-1H-benzo[d]imidazole-1,3(2H)-diyl) diacetate and its arylideneacetohydrazide derivatives, using ultrasonic irradiation and conventional heating. The compounds were confirmed by Nuclear magnetic resonance (NMR) (JEOL, Tokyo, Japan) and Fourier transform infrared spectroscopy (FTIR) spectroscopy (Thermoscientific, Waltham, MA, USA). The molecular structure and electronic properties of the studied compounds were predicted for the acetohydrazide hydrazones. These compounds exist as a mixture of configurational and conformational isomerism as well as amido-amidic acid tautomerism. The NMR spectral data proved the predominance of syn-E amido isomers. In addition, density functional theory (DFT) predicted stability in the gas phase and showed that syn-E amido isomers are the most stable in the presence of an electron donating group, while the anti-isomer is the most stable in the presence of electron-attracting substituents. The anticancer activity of these synthetic compounds 6a, 6b and 6c towards both colon cancer (HCT-116) and cervical cancer (HeLa) cells was examined by MTT assay and DAPI staining. The MTT assay revealed a strong antiproliferative effect against the cancer cells at low concentrations, and interestingly, no significant inhibitory action against the non-cancerous cell line, HEK-293. The IC50 values for HCT-116 were 29.5 + 4.53 µM, 57.9 + 7.01 µM and 40.6 + 5.42 µM for 6a, 6b, and 6c, respectively. The IC50 values for HeLa cells were 57.1 + 6.7 µM, 65.6 + 6.63 µM and 33.8 + 3.54 µM for 6a, 6b, and 6c, respectively. DAPI staining revealed that these synthesized benzimidazole derivatives caused apoptotic cell death in both the colon and cervical cancer cells. Thus, these synthetic compounds demonstrate encouraging anticancer activity as well as being safe for normal human cells, making them attractive candidates as anticancer agents.

Designing of Co0.5Ni0.5GaxFe2-xO4 (0.0 ≤ x ≤ 1.0) Microspheres via Hydrothermal Approach and Their Selective Inhibition on the Growth of Cancerous and Fungal Cells

The current study offers an efficient design of novel nanoparticle microspheres (MCs) using a hydrothermal approach. The Co_0.5Ni_0.5Ga_xFe_2−xO₄ (0.0 ≤ x ≤ 1.0) MCs were prepared by engineering the elements, such as cobalt (Co), nickel (Ni), iron (Fe), and gallium (Ga). There was a significant variation in MCs’ physical structure and surface morphology, which was evaluated using energy dispersive X-ray analysis (EDX), X-ray diffractometer (XRD), high-resolution transmission electron microscopy (HR-TEM), and scanning electron microscope (SEM). The anti-proliferative activity of MCs was examined by MTT assay and DAPI staining using human colorectal carcinoma cells (HCT-116), human cervical cancer cells (HeLa), and a non-cancerous cell line—human embryonic kidney cells (HEK-293). Post 72 h treatment, MCs caused a dose dependent inhibition of growth and proliferation of HCT-116 and HeLa cells. Conversely, no cytotoxic effect was observed on HEK-293 cells. The anti-fungal action was assessed by the colony forming units (CFU) technique and SEM, resulting in the survival rate of Candida albicans as 20%, with severe morphogenesis, on treatment with MCs x = 1.0. These findings suggest that newly engineered microspheres have the potential for pharmaceutical importance, in terms of infectious diseases and anti-cancer therapy.

Synthesis, Characterization, Anti-Cancer Analysis of Sr0.5Ba0.5DyxSmxFe8-2xO19 (0.00 ≤ x ≤ 1.0) Microsphere Nanocomposites

There is enormous interest in combining two or more nanoparticles for various biomedical applications, especially in anti-cancer agent delivery. In this study, the microsphere nanoparticles were prepared (MSNPs) and their impact on cancer cells was examined. The MSNPs were prepared by using the hydrothermal method where strontium (Sr), barium (Ba), dysprosium (Dy), samarium (Sm), and iron oxide (Fe_8−2xO₁₉) were combined, and dysprosium (Dy) and samarium (Sm) was substituted with strontium (Sr) and barium (Ba), preparing Sr_0.5Ba_0.5Dy_xSm_xFe_8−2xO₁₉ (0.00 ≤ x ≤ 1.0) MSNPs. The microspheres were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) techniques. The diffraction pattern of nanohexaferrites (NHFs) reflected the signature peaks of the hexagonal structure. The XRD revealed a pure hexagonal structure without any undesired phase, which indicated the homogeneity of the products. The crystal size of the nanoparticles were in the range of 22 to 36 nm by Scherrer’s equation. The SEM of MSNPs showed a semi-spherical shape with a high degree of aggregation. TEM and HR-TEM images of MSNPs verified the spherical shape morphology and structure that approved an M-type hexaferrite formation. The anti-cancer activity was examined on HCT-116 (human colorectal carcinoma) and HeLa (cervical cancer cells) using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and post-48 h treatment of MSNPs caused a dose-dependent inhibition of HCT-116 and HeLa cell proliferation and growth. Conversely, no significant cytotoxic effect was observed on HEK-293 cells. The treatments of MSNPs also induced cancer cells DNA disintegration, as revealed by 4′,6-diamidino-2-phenylindole (DAPI) staining. Finally, these findings suggest that synthesized MSNPs possess potential inhibitory actions on cancerous cells without harming normal cells.

Synthesis and Cytotoxic Activity of Novel Metal Complexes Derived from Methyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoate as Potential CDK8 Kinase Inhibitors

Several metal complexes of methyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoate derivatives were synthesized and tested for their anti-tumor activities. The ligands include 3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoic acid (1), 3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanehydrazide (2), and 3-(4-chlorophenyl)-N'-(4-(dimethylamino)benzylidene)-3-hydroxy-2,2-dimethylpropanehydrazide (3). The ligands were reacted with Cu (II), Ni (II), and La (III) ions. The formed complexes were characterized using elemental analysis (M%), molar conductivity in DMF (0.001 M), DTA, TG, FTIR, ICP-AES, and magnetic susceptibility. The chemical structures of the obtained complexes were interpreted, and their chemical formulas were postulated. The anti-cancer activities of these complexes were examined on human colorectal carcinoma cells (HCT-116) and also on normal cells (HEK-293). The 48 h post treatments showed that out of 12 compounds, 10 compounds showed inhibitory actions on HCT-116 cells, whereas two compounds did not show any inhibitory actions. Compounds 6c and 4a showed the highest inhibitory actions with IC50 = 0.154 and 0.18 mM and additionally compounds 3, 4b, and 6a with IC50 = 0.267, 0.205, and 0.284 mM, respectively. All tested compounds did not show any inhibitory action on normal HEK-293 cells. Molecular docking results provided a good evidence for activity of the lead compounds 3 and 4a as CDK8-CYCC kinase inhibitors, which may proposed the mechanism of action toward colon cancer therapy.

Novel Synthetic Routes to Prepare Biologically Active Quinoxalines and Their Derivatives: A Synthetic Review for the Last Two Decades

Quinoxalines, a class of N-heterocyclic compounds, are important biological agents, and a significant amount of research activity has been directed towards this class. They have several prominent pharmacological effects like antifungal, antibacterial, antiviral, and antimicrobial. Quinoxaline derivatives have diverse therapeutic uses and have become the crucial component in drugs used to treat cancerous cells, AIDS, plant viruses, schizophrenia, certifying them a great future in medicinal chemistry. Due to the current pandemic situation caused by SARS-COVID 19, it has become essential to synthesize drugs to combat deadly pathogens (bacteria, fungi, viruses) for now and near future. Since quinoxalines is an essential moiety to treat infectious diseases, numerous synthetic routes have been developed by researchers, with a prime focus on green chemistry and cost-effective methods. This review paper highlights the various synthetic routes to prepare quinoxaline and its derivatives, covering the literature for the last two decades. A total of 31 schemes have been explained using the green chemistry approach, cost-effective methods, and quinoxaline derivatives' therapeutic uses.

The synthesis and antiproliferative activity of new N-allyl quinoxalinecarboxamides and their O-regioisomers

We have designed a series of quinoxalinepeptidomimetic derivatives based on our previously reported scaffold in an attempt to find a promising lead compound.

Doxorubicin Delivered Using Nanoparticles Camouflaged with Mesenchymal Stem Cell Membranes to Treat Colon Cancer

PURPOSE

The primary goal of the present study was to design doxorubicin (DOX)-loaded superparamagnetic iron oxide (SPIO) nanoparticles (NPs) coated with mesenchymal stem cell (MSC) membranes and explore their effect on colon cancer in vitro and in vivo.

METHODS

DOX-SPIO NPs were coated with MSC membranes using an extruder, and the morphological characteristics of MSC membrane-camouflaged nanodrug (DOX-SPIO@MSCs) evaluated by transmission electron microscopy (TEM) and NP-tracking analysis. Drug loading and pH response were assessed by UV spectrophotometry. Intracellular colocalization was analyzed using NP-treated MC38 cells stained with 3,3'-dioctadecyloxacarbocyanine perchlorate and Hoechst 33342. Cellular uptake was analyzed using an inverted fluorescence microscope and flow cytometry and cytotoxicity evaluated by cell counting kit-8 assay. Biological compatibility was assessed by hemolysis analysis, immunoactivation test and leukocyte uptake experiments. Furthermore, intravenous injection of chemotherapy drugs into MC38 tumor-bearing C57BL/6 mice was used to study anti-tumor effects.

RESULTS

Typical core-shell NP structures were observed by TEM. Particle size remained stable in fetal bovine serum and phosphate-buffered saline (PBS). Compared with DOX-SPIO, DOX-SPIO@MSCs improved cellular uptake efficiency, enhanced anti-tumor effects, and reduced the immune system response. Animal experiments demonstrated that DOX-SPIO@MSCs enhanced tumor treatment efficacy while reducing systemic side effects.

CONCLUSION

Our experimental results demonstrate that DOX-SPIO@MSCs are a promising targeted nanocarrier for application in treatment of colon cancer.

Synthesis and Biological Activities of Some New Benzotriazinone Derivatives Based on Molecular Docking; Promising HepG2 Liver Carcinoma Inhibitors

In one-pot strategy, diazotization of methyl anthranilate 5 followed by addition of amino acid ester hydrochloride, we have prepared methyl-2-(4-oxobenzotriazin-3(4H)-yl)alkanoates 6a-c. Starting with hydrazides 7a,b, N-alkyl-2-(4-oxobenzotriazin-3(4H)-yl)alkanamides 9-10(a-h) and methyl-2-(2-(4-oxobenzotriazin-3(4H)-yl)alkanamido)alkanoates 11-12(a-e) were prepared via azide coupling. Hydrazones 13-15 were prepared via condensation of hydrazides 7a,b with 4-methoxybenzaldehyde, 4-dimethylaminobenzaldehyde, and/or arabinose. Molecular docking was done for synthesized compounds using MOE 2008-10 software. The compounds 9a, 12a, 12c, 13a, 13b, and 14b have the most pronounced strong binding affinities toward the target E. coli Fab-H receptor, whereas compounds 3, 11e, 12e, and 13a have the most pronounced strong binding affinities toward the target vitamin D receptor. The in vitro antibacterial activities of the highest binding affinity docked compounds were tested against E. coli, Staphylococcus aureus, and Salmonella spp. Majority of the tested compounds showed effective positive results against E. coli, while they were almost inactive against Staphylococcus aureus and Salmonella spp . The in vitro cytotoxic activities of the highest binding affinity-docked compounds were tested against the human liver carcinoma cell line (HepG2). Some compounds showed potent cytotoxic activity with low IC50 values, especially for 3 (6.525 μM) and 13a (10.97 μM) than that for standard drug doxorubicin (2.06 μM).

Newly synthesized 3-(4-chloro-phenyl)-3-hydroxy-2,2-dimethyl-propionic acid methyl ester derivatives selectively inhibit the proliferation of colon cancer cells

A series of 24 compounds were synthesized based on structure modification of the model methyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoate as potent HDACIs. Saponification and hydrazinolysis of the model ester afforded the corresponding acid and hydrazide, respectively. The model ester was transformed into the corresponding trichloroacetimidate or acetate by the reaction with trichloroacetonitrile and acetic anhydride, respectively. N-Alkyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropan-amides and methyl-2-[(3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoyl)amino] alkanoates were obtained by the reaction of corresponding acid or hydrazide with amines and amino acid esters via DCC and azide coupling methods. Methyl-3-aryl-3-(4-chlorophenyl)-2,2-dimethylpropanoates were obtained in good yields and short reaction time from the corresponding trichloroacetimidate or acetate by the reaction with C-active nucleophiles in the presence of TMSOTf (0.1 eq.%) via C–C bond formation. The antiproliferative and apoptotic activity were further studied with molecular docking. The 48 post-treatments showed that out of 24 compounds, 12 compounds showed inhibitory actions on HCT-116 cells, we have calculated the inhibitory action (IC₅₀) of these compounds on HCT-116 and we have found that the IC₅₀ values were in between 0.12 mg mL⁻¹ to 0.81 mg mL⁻¹. The compounds (7a & 7g) showed highest inhibitory activity (0.12 mg mL⁻¹), whereas compound 7d showed the lowest inhibitory activity (0.81 mg mL⁻¹). We have also examined inhibitory action on normal and non-cancerous cells (HEK-293 cells) and confirmed that action of these compounds was specific to cancerous cells. The cancerous cells were also examined for nuclear disintegration through staining with DAPI, (4′,6-diamidino-2-phenylindole) is a blue-fluorescent DNA stain, and we have found that there was loss of DAPI staining in the compound treated cancerous cells. The compounds were found to potentially act through the HSP90 and TRAP1 mediated signaling pathway. Compounds 7a and 7g showed the highest selectivity to TRAP1 which explained its superior activity.

A series of 24 compounds were synthesized based on structure modification of the model methyl-3-(4-chlorophenyl)-3-hydroxy-2,2-dimethylpropanoate as potent HDACIs.