Derivatives 2b Research Articles

Fluorescent Probes to Image the KCa3.1 Channel in Tumor Cells

Background/Objectives: The Ca2+-activated K+ channel KCa3.1 is not only involved in physiological processes such as immune reactions and control of vascular tone, but is highly expressed in various tumor entities. Thus, imaging of KCa3.1 channels comes into focus for the localization of high channel density, i.e., for tumor diagnosis. In particular, the physicochemical properties of the fluorescent probes should be improved compared to existing probes. Methods: The small molecule inhibitor of the KCa3.1 channel, senicapoc, was used as a warhead and was coupled with different fluorescent dyes. After synthesis of the novel probes, their physicochemical properties (lipophilicity, photophysical properties) and their ability to image KCa3.1 channels in A549-3R lung tumor cells were determined. Results: In order to increase the polarity and quantum yield of reported fluorescent probes, three strategies were followed: (1) An F-atom at the B-atom of bodipy-labeled senicapoc derivatives 9a, 9b, and 15a was replaced by a OCH3 moiety, which decreased the logP value by one log-unit. (2) The p-phenylene moiety of the linker was replaced by an aliphatic tetramethylene linker decreasing the lipophilicity by 0.3–0.5 log-units. (3) Instead of bodipy dyes, fluorescein was coupled with the senicapoc warhead resulting in very polar probes 21a and 21b with low logP values of 1.5 and 1.3, respectively. Introduction of an ethyl moiety at the bodipy core increased the quantum yield, which resulted in the best punctate staining pattern of fixed and living A549-3R lung tumor cells with the ethylbodipy-labeled senicapoc derivative 10b. The specificity was shown by various control experiments. Co-staining with 10b and an antibody did not result in overlapping signals. Conclusion: The well-balanced lipophilicity and fluorescent quantum yield render the ethylbodipy-labeled senicapoc derivative 10b a very good probe to image selectively KCa3.1 ion channels in fixed and living tumor cells. It was hypothesized that the antibody binds selectively at the closed channel (58.5%), whereas the senicapoc–bodipy conjugate 10b binds selectively at the open channel (41.5%). The ratio 58.5:41.5 reflects the ratio of the ion channel in closed and open conformations.

Molecular Orbital Tuning of Pentacene-Based Organic Semiconductors through N-Ethynylation of Dihydrodiazapentacene.

This study explores the concept of molecular orbital tuning for organic semiconductors through the use of N,N'-diethynylated derivatives of 6,13-dihydro-6,13-diazapentacene (2a and 2b). These novel molecules maintain the same molecular geometry and π-π stacking as their parent pentacene derivatives (1a and 1b), as confirmed by X-ray crystallography. However, they exhibit altered frontier molecular orbitals in terms of the phase, nodal properties, and energy levels. Theoretical calculations based on crystal structures indicate that 2a and 2b could significantly enhance the hole mobilities of the parent compounds by improving the hole transfer integral. Organic field-effect transistors (OFETs) of 1a and 2a were fabricated by using dip-coating and bar-coating methods. Both types of devices for 2a demonstrated a hole mobility exceeding 1 cm2 V-1 s-1, more than twice that of the respective devices for 1a. Additionally, unlike its pentacene parent, 2a is transparent to visible light and exhibits significantly enhanced environmental stability against light and air, making it a promising candidate for broader applications in organic electronic devices.

Synthesis and in vitro leishmanicidal activity of novel N-arylspermidine derivatives.

This work describes the synthesis and biological evaluation of hitherto unknown N-arylspermidine derivatives 3. Compounds 3 were efficiently prepared from cyclic amidines through a novel synthetic approach comprising alkylation with ω-halonitriles followed by reduction. The cyclic N-arylamidine directs the alkylation to the unsubstituted nitrogen and also provides the N-benzyl group present in the triamine after simultaneous reduction of the resulting quaternary salt 2 and the cyano group. The N-aryl spermidines were tested in Leishmania infantum promastigotes and also in the more challenging form intracellular amastigotes. The compounds toxicity was also assessed in two cell lines, THP-1 and HepG2. In silico physicochemical and ADME predictions were also carried out. Eight out of ten compounds displayed EC50 around 5µM against L. infantum intracellular amastigotes. Among them, derivatives 3c, 3d, and 3h showed potency in the low micromolar range with SI>5 and suitable predicted physicochemical ADME properties. The antileishmanial activity of the compounds would rely on the N-arylspermidine moiety, as assessed by evaluation of related substructures which were inactive. This first series of compounds, among which two derivatives (3b,h) displayed EC50 values comparable to Miltefosine, represent a good starting point for further studies and multiparametric optimization to obtain more potent and selective candidates for the treatment of this neglected tropical disease.

Phthalazine Derivatives as VEGFR‐2 Inhibitors: Docking, ADMET, Synthesis, Design, Anticancer Evaluations, and Apoptosis Inducers

ABSTRACTNew phthalazine‐derived inhibitors for VEGFR‐2 were synthesized for anticancer evaluations. Also, docking studies were performed to explore the suggested binding orientations of the novel derivatives inside the binding site of VEGFR‐2. The achieved biological data were extremely interrelated to that of docking study. In specific, derivative 3f was the greatest effective compound against HepG2 and MCF‐7 cancer cell lines with IC50 = 0.17 ± 0.01 and 0.08 ± 0.01 µM individually. The six highly active derivatives 3b, 3e, 3f, 3g, 6a, and 6b were estimated for their VEGFR‐2 inhibitory effects. Derivative 3f was the greatest effective compound which inhibited VEGFR‐2 at IC50 = 0.0557 ± 0.002 µM. The activities of 3f were assessed against MCF‐7 cancer cells for apoptosis induction, cell cycle distribution, and growth inhibition. Compound 3f induced early apoptosis (21.44%) by more than 36 folds over the control (0.59%). The obtained results showed that compound 3f induced necrotic effect (6.03%) by more than threefolds over the control (1.75%). On the other hand, compound 3f improved the level of the pro‐apoptotic protein; Bax by approximately fivefolds. Moreover, compound 3f noticeably decreased the levels of the anti‐apoptotic proteins Bcl‐2 by nearly fourfolds in comparison to the control. In addition, derivative 3f remarkably enhanced the Bax/Bcl2 ratio by nearly 18 folds, as compared to the control. Finally, our derivatives 3f, 3g, and 6b revealed good in silico considered ADMET profile in comparing to sorafenib.

Natural benzofuran derivatives as promising scaffold for alleviating Alzheimer symptoms: acetylcholinesterase inhibition, structure activity relationship and in silico studies

Three isolated natural benzofuran compounds 1a-c and four semi-synthesized benzofuran derivatives 2a,b and 3a,b were evaluated for their in vitro acetylcholinesterase inhibition assay. Most of the tested compounds showed moderate activity with IC50 ranged from 102.4 ± 5.72 µM to 565.75 ± 4.17 µM, the most potent compound was kellin 1a with IC50 102.4 ± 5.72 µM. The kellin derivatives 1a, 2a and 3a bearing additional methoxyl group showed more inhibition activity than its analogues of visnagin derivatives 1b,c, 2b and 3b. The in silico investigation on the seven benzofuran derivatives matched our in vitro acetylcholinesterase results and explains the similarity in structures between the benzofuran compounds and donepezil drug. khellin had the best pharmacophore features among the studied compounds, the best fit score 1.862 and best dock score −9.135. In addition, our in silico study showed clearly that compounds carrying additional hydrophobic group had more potent activity through matched more ligand features.

Synthesis and structural proof of novel oxazolo[5,4-d]pyrimidine derivatives as potential VEGFR2 inhibitors. In vitro study of their anticancer activity

The present study aimed to design and synthesize novel 6-N-benzyloxazolo[5,4-d]pyrimidin-7(6H)-imines 3a-j as possible inhibitors of the vascular endothelial growth factor receptor 2 (VEGFR2). The structures of newly synthesized compounds were confirmed via spectral and crystallographic data. NOESY spectroscopy was very useful in distinguishing between 6-N-benzyl-7(6H)-imine 3a and isomeric 7-N-benzyl-7-amine 4a, obtained by Dimroth rearrangement. Molecular docking at the VEGFR2 active site was performed, indicating that 7(6H)-imines should have a similar binding mode as type II VEGFR2 inhibitors. All derivatives were preliminary evaluated for in vitro cytotoxic activity against four human cancer cell lines, including lung cancer (A549), colorectal cancer (HT-29), melanoma (A375), breast cancer (MCF7), using tivozanib as a reference drug, and some of them were subjected to VEGFR2 inhibition, anti-angiogenic activity, and human serum albumin (HSA) binding assays. Only 6-N-2,4-dimethoxybenzyl derivative 3h appeared to be as active as tivozanib against all tested anticancer cell lines but equally toxic to healthy normal human dermal fibroblasts (NHDF). Derivatives 3f (6-N-2-methybenzyl) and 3b (6-N-4-methylbenzyl) have revealed slightly worse activity than 3h. They were cytotoxic agents comparable to tivozanib against three anticancer lines, but only 3b showed no cytotoxicity against NHDF. Both 3b and 3h proved to be effective VEGFR2 inhibitors with IC50 values comparable to that of tivozanib. Notably, 4a did not actually show an anticancer effect against the tested cancer lines, in contrast to isomeric 3a. In an angiogenesis assay, 3f and 3h significantly suppressed the tube formation ability of human dermal microvascular endothelial cells (HMEC-1), indicating their anti-angiogenic potential. The interactions between these compounds and HSA appeared to occur at two specific binding sites.

The charge transport properties of dicyanomethylene-functionalised violanthrone derivatives.

The study of organic small molecule semiconductor materials as active components of organic electronic devices continues to attract considerable attention due to the range of advantages these molecules can offer. Here, we report the synthesis of three dicyanomethylene-functionalised violanthrone derivatives (3a, 3b and 3c) featuring different alkyl substituents. It is found that the introduction of the electron-deficient dicyanomethylene groups significantly improves the optical absorption compared to their previously reported precursors 2a-c. All compounds are p-type semiconductors with low HOMO-LUMO gaps (≈1.25 eV). The hole mobilities, measured from fabricated organic field-effect transistors, range from 3.6 × 10-6 to 1.0 × 10-2 cm2 V-1 s-1. We found that the compounds featuring linear alkyl chains (3b and 3c) displayed a higher mobility compared to the one with branched alkyl chains, 3a. This could be the result of the more highly disordered packing arrangement of this molecule in the solid state, induced by the branched side chains that hinder the formation of π-π stacking interactions. The influence of dicyanomethylene groups on the charge transport properties was most clearly observed in compound 3b which has a 60-fold improvement in mobility compared to 2b. This study demonstrates that the choice of the solubilising group has a profound effect on the hole mobility on these organic semiconductors.

Synthesis and antifungal activity of novel amide derivatives from quinic acid against the sweet potato pathogen Ceratocystis fimbriata.

Ceratocystis fimbriata is a fungal pathogen that infects sweet potato roots, producing enormous economic losses. Cyclic polyhydroxy compound quinic acid is a common metabolite synthesized in plant tissues, including sweet potato tubers, showing weak antifungal properties. Although several O-acylated quinic acid derivatives have been synthesized and found in nature and their antifungal properties have been explored, derivatives based on modification of the carboxylic acid have never been evaluated. In this study, amide derivatives were synthesized via linkage of amines with the carboxylic acid moiety of quinic acid. Derivatives with high dipolar moments and a low number of rotatable bonds showed greater antifungal activities toward C. fimbriata in vitro than quinic and chlorogenic acids. Derivative 5b, which was synthesized by coupling p-aminobenzoic acid (pABA) with quinic acid, had the greatest antifungal activity. 5b showed iron(II)-chelating properties and reduced ergosterol content in C. fimbriata cells, causing irregularities in the fungal cell wall and inhibiting conidia agglutination. Application of 3 mm 5b reduced black rot symptoms in sweet potatoes by 70.1%. Collectively, derivatization of the carboxylic acid from quinic acid was demonstrated to be a suitable strategy to improve the antifungal properties of this compound. This study reveals a new efficient strategy for management of the sweet potato pathogen C. fimbriata. © 2024 Society of Chemical Industry.

New vatalanib analogs: Design, synthesis, in silico study and biological evaluation for anticancer activity

In our attempts to improve pharmacokinetics and pharmacodynamics characters of vatalanib, four strategies of the drug design were applied to design and synthesis new quinoxaline based vatalanib analogs. Antiproliferative activities of the synthesized compounds were investigated against two tumor cell lines (HepG2 and HCT‐116) using vatalanib as a positive control. The new candidates showed promising anticancer activity against two tested cancer cell lines with IC50 values ranging from 6.04 ± 0.19 to 100.15 ± 3.26 µM, in particular compounds 11b and 11c which were more potent than vatalanib. The most potent was the 4-benzoylquinoxaline derivative 11b (IC50 = 6.04 ± 0.19 µM and 15.58 ± 0.58 µM) compared to vatalanib (IC50 of 25.27 ± 0.84 µM and 43.91 ± 1.64 µM) against HepG2 and HCT116, respectively. The selectivity indices of 11b were found to be approximately 14 and 5 towards HepG2 and HCT116, respectively. While vatalanib showed selectivity indices of about 5 and 3 towards HepG2 and HCT116, respectively. The most promising compound 11b was further investigated in HepG‐2 cells for its apoptotic effect, cell cycle arrest and in vitro VEGFR-2 inhibitory activity as the main mechanisms of cell death. It was found that 11b can induce apoptosis and arrest the cell cycle at the at G1 phase in addition to, compound 11b showed effective inhibition of VEGFR-2 with IC50 of 0.918 ± 0.033 µM compared to vatalanib (IC50 of 0.265 ± 0.009 µM). Deep computational studies were created for the designed compounds including molecular docking, physicochemical properties, profiling pharmacokinetics, ADMET studies, and toxicity predictions to evaluate the prospective drug candidates. The results of the docking study were consistent with biological testing, furthermore, in silico ADMET study revealed the superior pharmacokinetics characters of the new candidates over vatalanib. So, the current work suggests that the 4-benzoylquinoxaline-1-yl-acetamide derivatives, especially 11b, can serve as lead molecules for development of new effective anticancer drugs.

Synthesis of S-alkylated oxadiazole bearing imidazo[2,1-b]thiazole derivatives targeting breast cancer: In vitro cytotoxic evaluation and in vivo radioactive tracing studies

Breast cancer is the most common invasive cancer diagnosed in women, accounting for most cancer-related fatalities globally. Numerous investigations have revealed that breast cancer is characterized by abnormal expression and maintenance of EGFR levels. In terms of structural study and optimization of several EGFR inhibitors, two series of oxadiazole bearing imidazo[2,1-b]thiazole derivatives were designed and synthesized as potential EGFR inhibitors and assessed for their antitumor activity at NCI-USA. Four derivatives 3b, 3c, 3d and 3e elicited remarkable GI% against MDA-MB-468, T-47D and MCF-7 breast cancer cell lines. Thereafter, MTT assay was performed to reveal that compounds 3b (IC50 = 2.27 µM) and 3d (IC50 = 1.46 µM) showed promising cytotoxic activity against MCF-7 and MDA-MB-468 cell lines, respectively, compared to their reference drugs. Compounds 3b, 3d and 3e revealed good selectivity toward tumor cells with reasonable safety profile when tested against the normal cell line MCF-10a. In vitro EGFR inhibitory assay demonstrated that compounds 3b (IC50 = 0.099 µM) and 3d (IC50 = 0.086 µM) exhibited comparable inhibitory activity to the standard drug erlotinib (IC50 = 0.046 µM). A flow cytometric analysis demonstrated that derivatives 3b and 3d arrested the cell cycle at the S phase in MCF-7 and MDB-MB-468, respectively. Furthermore, the most active derivative 3d was subjected to in vivo radioactive studies. In-vivo biodistribution of 99mTc-3d complex showed a notable elevated accumulation in the targeted sarcoma muscle, indicating the targeting capacity of compound 3d in the tumor of sarcoma mice model. The binding mode of compounds 3b and 3d with EGFR was studied by molecular docking and was further inspected by molecular dynamic simulations. Both compounds were shown to be stable during the course of simulation and demonstrated a plausible interaction pattern with the EGFR binding pocket.

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.

Synthesis of bis-Chalcones Based on Green Chemistry Strategies and Their Cytotoxicity Toward Human MeWo and A375 Melanoma Cell Lines.

Chalcone is an aromatic ketone that forms the central core of many important biological compounds. Chalcone derivatives show various biological activities, especially anti-inflammatory, antibacterial, antioxidant, and anticancer activities, and also inhibit melanoma cell growth. In this study, we synthesized chalcone compounds with bis-chalcone's chemical structure under microwave (MW) and microwave-ultrasound (MW-US) conditions and compared them to chalcones produced using the classical synthesis method. All bis-chalcones were synthesized with terephthalaldehyde and an appropriate aromatic ketone as substrates in Claisen-Schmidt condensation. All the obtained compounds were tested regarding their roles as potential anticancer agents. The cytotoxic effect of the bis-chalcones against human MeWo and A375 melanoma cell lines was investigated through colorimetric MTT and SRB assays. The data were analyzed statistically. In the case of the synthesis of bis-chalcones, it was determined that the use of green conditions supported by the MW or MW-US factors led to an increase in the yield of the final products and a reduction in the reaction time compared to the classic method. The biological results showed the high cytotoxic effect of bis-chalcones. The present results show the compounds' high antiproliferative and cytotoxic potential, especially for the two selected bis-chalcone derivatives (3b and 3c), in particular, at concentrations of 50 μM-200 μM at 24, 48 h, and 72 h of incubation. The use of MW and US for the synthesis of bis-chalcones significantly improved the process compared to the classical method. The derivatives containing two hydroxy and two methoxy groups were the most effective against the tested cancer cells.

Novel phthalocyanines bearing fluoro-methylquinolin substituents: Synthesis, characterization, photophysical and photochemical properties

The novel 4-((6-fluoro-2-methylquinolin-4-yl)oxy)phthalonitrile (3a), 3-((6-fluoro-2-methylquinolin-4-yl)oxy)phthalonitrile (3b), tetra 6-fluoro-2-methylquinolin-4-yl)oxy substituted zinc(II) phthalocyanines (4a and 4b) and their water soluble derivatives (5a and 5b) were prepared. The proposed structures of novel compounds were comfirmed via FT-IR, 1HNMR , UV–Vis and MALDI-TOF mass data. The aggregation tendency, fluorescence quantum yield, singlet oxygen quantum yield and photodegradation measurements were performed to examine the photodynamic therapy potential of both peripherally tetra substituted zinc(II) phthalocyanines (4a and 4b) and the water soluble quaternized tetra substituted zinc(II) phthalocyanines (5a and 5b). The result showed that both the novel tetra 6-fluoro-2-methylquinolin-4-yl)oxy substituted zinc(II) phthalocyanines (4a and 4b) and their water soluble derivatives (5a and 5b) could be used as photosensitizer agents in PDT thanks to their lack of aggregation tendency, having sufficient fluorescence emission for monitoring and produce high amount of singlet oxygen to destroy cancerous tissues and having moderate photostability.

New S-substituted-3-phenyltetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4(3H)-one scaffold with promising anticancer activity profile through the regulation and inhibition of mutated B-RAF signaling pathway.

Novel 3-phenyltetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine derivatives were synthesized and screened for their antiproliferative activity against a panel of 60 cancer cell lines. Derivatives 5b, 5f, and 9c showed significant antitumor activity at a single dose with mean growth inhibition of 55.62%, 55.79%, and 71.40%, respectively. These compounds were further investigated against HCT-116, colon cancer cell line, and FHC, normal colon cell line. Compound 9c showed the highest activity with IC50 = 0.904 ± 0.03 µM and SI = 20.42 excelling doxorubicin which scored IC50 = 2.556 ± 0.09 µM and SI = 6.19. Compound 9c was also the most potent against B-RAFWT and mutated B-RAFV600E with IC50 = 0.145 ± 0.005 and 0.042 ± 0.002 µM, respectively in comparison with vemurafenib with IC50 = 0.229 ± 0.008 and 0.038 ± 0.001 µM, respectively. The cell cycle analysis showed that 9c increased the cell population and induced an arrest in the cell cycle of HCT-116 cancer cells at the G0-G1 stage with 1.23-fold. Apoptosis evaluation showed that compound 9c displayed an 18.18-fold elevation in total apoptosis of HCT-116 cancer cells in comparison to the control. Compound 9c increased the content of caspase-3 by 3.52-fold versus the control. A molecular modeling study determined the binding profile and interaction of 9c with the B-RAF active site.

Synthesis and Bioevaluation of New Stable Derivatives of Chrysin-8-C-Glucoside That Modulate the Antioxidant Keap1/Nrf2/HO-1 Pathway in Human Macrophages

Background/Objectives: The beneficial effects of the flavonoid chrysin can be reduced by its poor oral bioavailability. It has been shown that chrysin-8-C-glucoside (1) has a better absorption capability. The aim of this study was to evaluate the antioxidant and anti-inflammatory activity of this glucoside, as well as the respective hexa-acetate derivative 1a and the hexa-ethyl carbonate derivative 1b since the inclusion of moieties in bioactive molecules may increase or modify their biological effects. Methods: THP-1 macrophages were used to determine the viability in the presence of chrysin derivatives, and non-cytotoxic concentrations were selected. Subsequently, lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) production and inflammatory mediators were examined. The involvement of chrysin derivatives with the Keap1 and Nrf2 antioxidant system was determined by docking and Western blotting studies. Results: Our data demonstrated, for the first time, that pretreatment with the three compounds caused a significant reduction in LPS-induced reactive oxygen species (ROS) production and pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin 1β (IL-1β) levels, as well as in cyclooxygenase 2 (COX-2) expression. The mechanisms underlying these protective effects were related, at least in part, to the competitive molecular interactions of these phenolic compounds with Kelch-like ECH-associated protein 1 (Keap1)–nuclear factor erythroid 2-related factor 2 (Nrf2), which would allow the dissociation of Nrf2 and its translocation into the nucleus and the subsequent up-regulation of hemo-oxygenase 1 (HO-1) expression. Conclusions: Compared to the 8-C-glucoside parent chrysin, compound 1a exhibited the strongest antioxidant and anti-inflammatory activity. We hypothesized that the incorporation of an acetate group (1a) may reduce its polarity and, thus, increase membrane permeability, leading to better pharmacological activity. These findings support the potential use of these phenolic compounds as Nrf2 activators against oxidative-stress-related inflammatory diseases.

Chemical Upcycling of Expired Pharmaceuticals as a Source of Value-Added Chemicals for Organic Synthesis and Medicinal Chemistry.

Pharmaceutical and veterinary products are a class of contaminants of emerging concern, and their presence in the environment is due to continuous and incorrect disposal. Environmental scientists have been accumulating data on their adverse effects on animal populations since toxicological effects on wildlife were first published. Therefore, recycling strategies are needed. Valuable active ingredients can be extracted from expired pharmaceuticals and recycled according to various strategies. In an effort to reveal the potential of the chemical upcycling of expired pharmaceuticals, the active ingredients gabapentin and pregabalin were extracted and used as starting materials to prepare a small collection of promising substrates endowed with functionalities and structural three-dimensionality. Gabapentin 1 was transformed into aminoalcohol 3, spiroamine 4, and the bioactive azaspirolactam 5. The lactam analog 6 was synthesized from pregabalin 2. Due to the biological profile of 5 and the structural similarity of the N-alkylated derivatives 5l and 6b with the drug piracetam, a collection of potentially bioactive structural analogs 5a-l and 6a-b were also prepared. Simple extraction, synthesis, and purification procedures were used as a means of chemical and economic revaluation, resulting in moderate to good yields at a low cost.

Anti-Diabetic Activities and Molecular Docking Studies of Aryl-Substituted Pyrazolo[3,4-b]pyridine Derivatives Synthesized via Suzuki Cross-Coupling Reaction.

Pyrazolo[3,4-b]pyridine scaffolds have been heavily exploited in the development of nitrogen-containing heterocycles with numerous therapeutic applications in the field of medicinal and pharmaceutical chemistry. The present work describes the synthesis of eighteen biaryl pyrazolo[3,4-b]pyridine ester (6a-i) and hydrazide (7a-i) derivatives via the Suzuki cross-coupling reaction. These derivatives were subsequently screened for their therapeutic potential to inhibit the diabetic α-amylase enzyme, which is a key facet of the development of anti-diabetic agents. Initially, the ethyl 4-(4-bromophenyl)-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]pyridine-6-carboxylate 4 was synthesized through a modified Doebner method under solvent-free conditions, providing an intermediate for further derivatization with a 60% yield. This intermediate 4 was subjected to Suzuki cross-coupling, reacting with electronically diverse aryl boronic acids to obtain the corresponding pyrazolo[3,4-b]pyridine ester derivatives (6a-i). Following this, the biaryl ester derivatives (6a-i) were converted into hydrazide derivatives (7a-i) through a straightforward reaction with hydrazine monohydrate and were characterized using 1H-NMR, 13C-NMR, and LC-MS spectroscopic techniques. These derivatives were screened for their α-amylase inhibitory chemotherapeutic efficacy, and most of the biaryl ester and hydrazide derivatives demonstrated promising amylase inhibition. In the (6a-i) series, the compounds 6b, 6c, 6h, and 6g exhibited excellent inhibition, with almost similar IC50 values of 5.14, 5.15, 5.56, and 5.20 μM, respectively. Similarly, in the series (7a-i), the derivatives 7a, 7b, 7c, 7d, 7f, 7g, and 7h displayed excellent anti-diabetic activities of 5.21, 5.18, 5.17, 5.12, 5.10, 5.16, and 5.19 μM, respectively. These in vitro results were compared with the reference drug acarbose (IC50 = 200.1 ± 0.15 μM), demonstrating better anti-diabetic inhibitory activity in comparison to the reference drug. The in silico molecular docking study results were consistent with the experimental biological findings, thereby supporting the in vitro pharmaceutical efficacy of the synthesized derivatives.

Exploring Acyl Thiotriazinoindole Based Pharmacophores: Design, Synthesis, and SAR Studies with Molecular Docking and Biological Activity Profiling against Urease, α-amylase, α-glucosidase, Antimicrobial, and Antioxidant Targets.

A diminutive chemical library of acyl thiotriazinoindole (ATTI) based bioactive scaffolds was synthesized, instigated by taking the economical starting material Isatin, through a series of five steps. Isatin was first nitrated followed by the attachment of pentyl moiety via nucleophilic substitution reaction. The obtained compound was reacted with thiosemicarbazide to obtain thiosemicarbazone derivative, which was eventually cyclized using basic conditions in water as solvent. Finally, the reported series was obtained through reaction of nitrated thiotriazinoindole moiety with differently substituted phenacyl bromides. The synthesized compounds were characterized using NMR spectroscopy and elemental analysis. Finally, the synthesized motifs were scrutinized for their potential to impede urease, α-glucosidase, DPPH, and α-amylase. Compound 5h with para cyano group manifested the most pivotal biological activity among all, displaying IC50 values of 29.7 ± 0.8, 20.5 ± 0.5 and 36.8 ± 3.9µM against urease, α-glucosidase, and DPPH assay, respectively. Simultaneously, for α-amylase compound 5g possessing a p-CH3 at phenyl ring unfolded as most active, with calculated IC50 values 90.3 ± 1.1µM. The scaffolds were additionally gauged for their antifungal and antibacterial activity. Among the tested strains, 5d having bromo as substituent exhibited the most potent antibacterial activity, while it also demonstrated the highest potency against Aspergillus fumigatus. Other derivatives 5b, 5e, 5i, and 5j also exhibited dual inhibition against both antibacterial and antifungal strains. The interaction pattern of derivatives clearly displayed their SAR, and their docking scores were correlated with their IC50 values. In molecular docking studies, the importance of interactions like hydrogen bonding was further asserted. The electronic factors of various substituents engendered variety of interactions between the ligands and targets implying their importance in the structures of the synthesized heterocyclic scaffolds. To conclude, the synthesized compounds had satisfactory biological activity against various important targets. Further studies are therefore encouraged by attachment of different substitutions in the structure at various positions to enhance the activity of these compounds.

Phytotoxic and Cytogenetic Assessment of Glycerol Triazole Derivatives in Model Plants and Weeds.

Weed invasion represents a challenge for farmers, who typically manage it with herbicides. However, this approach raises concerns about environmental and human health, as well as increasing resistance in these plants with continued use. Therefore, exploring alternative methods, such as heterocyclic compounds, triazoles, is essential due to their biological and environmental relevance. This study aimed to evaluate the effects of twelve 1,2,3-triazoles on the germination and early development of Lactuca sativa, Bidens pilosa, and Lolium multiflorum, as well as their impact on cell division in the cells of L. sativa. Triazole derivatives 4a, 4b, 4c, 4g, 4h, 4i, 4k, and 4l exhibited phytotoxicity, showing varying levels of inhibition in germination, germination speed index, and root growth. Chlorinated compounds were the most detrimental to lettuce development. B. pilosa was notably affected by compounds 4h, 4i, 4k, and 4l, while L. multiflorum responded most to triazoles 4c and 4l, with effectiveness comparable to that of the herbicide glyphosate. All derivatives, except 4l, exhibited aneugenic mechanisms of action, and 4a, 4b, 4c, 4e, 4f, and 4g showed clastogenic effects. This study demonstrated the potential of triazoles as effective agents against weed growth, with mechanisms that warrant further investigation for agricultural applications.

Benzylhydroxamic acids as inhibitors of insulin regulated aminopeptidase (IRAP)

With the objective of finding new classes of cognitive enhancers with potential for the treatment of neurodegenerative disorders, such as Alzheimer's disease, small molecule inhibitors of insulin-regulated aminopeptidase (IRAP) were designed and synthesized. IRAP is a member of the M1 family of zinc aminopeptidases and is abundantly expressed in areas of the brain associated with cognition, such as the amygdala, hippocampus and cerebral cortex. IRAP inhibitors were previously shown to enhance memory and learning in animal models. A comprehensive high throughput screening of 400,000 small molecules from the European Lead Factory library provided a series of 50 promising compounds in a qualified hit list (QHL). More than 30 IRAP inhibitors with an IC50 below 3.5 μM were identified. Herein, selected compounds from this QHL were assayed for solubility and permeability. Most of the selected compounds displayed good solubility, but further permeability studies on the best compounds revealed low blood brain barrier (BBB) permeability and high efflux in cells overexpressing P-gp pumps, rendering them less promising as starting points in drug discovery processes. Two compounds from the QHL were prioritized for further structural optimization; the pyridyl-substituted isoxazole 1a (QHL27) and the benzylhydroxamic acid derivative 1b (QHL1), both demonstrating fair BBB permeability and no indication of efflux. While our attempts to improve the isoxazole derivative 1a were not fruitful, a structural modification of 1b to provide the chloro-substituted benzylhydroxamic acid 14b resulted in a ten-fold improvement of the IRAP inhibition with an IC50 value of 60 nM. The binding modes of 1b and 14b were determined by free energy perturbation (FEP) analysis performed on candidate docking poses, determining a binding mode that accurately explained the experimental SAR. Further FEP studies of compound 14b suggested that it exhibits selectivity towards IRAP over Aminopeptidase N (APN), indicating its potential for targeted therapeutic applications.