Search Results (126)

A number of 1D and 2D NMR techniques, such as ¹H, ¹³C, DEPT 135, ¹H-¹H COSY, HSQC, and HMBC, were utilized for the structure verification of 4-(8-propyl-2,4-dithioxo-1,3-diazaspiro[4.5]decan-3-yl)spiro[1,5-dihydro-1,5-benzodiazepine-2,3′-indoline]-2′-one). The NMR spectra provided evidence for the tautomeric conversion of the compound. The completely assigned NMR data was supported additionally by ATR. Full article

NADPH oxidase enzymes (NOXs) are a family of enzymes generating superoxide, which form reactive oxygen species. NOX2 activity is a causative agent for the progression of many diseases: neurodegenerative, cardiovascular, immune dysregulations, and even hereditary diseases and cancer. Administering antioxidants helps in inhibiting NOX2 activity; however, the development of selective inhibitors may provide greater improvement in the therapy of diseases. Here, an optimized synthesis of two most promising NOX2 inhibitors based on the 3-(indolin-6-yl)-4-(N-pyrazole-sulfonamide)-1H-pyrrolo [2,3-b]pyridine structure, namely, GSK2795039 and NCATS-SM7270, and an isomeric derivative of the same class, IMBIOC-1, is reported. The new modified procedures simplify the isolation, reduce byproduct formation, and improve the yields in 0.1–1 g scale preparations. Molecular modeling of the structures of NOX2 complexes with inhibitors validated their binding at the same site as NADPH, with IMBIOC-1 forming the largest number of intermolecular interactions with the NOX2 active site. Testing the effects of the compounds on amyloid beta-induced oxidative stress and toxicity in HMC3 microglial cells showed that all three inhibitors completely prevented the pathological amyloid-beta effect. At the same time, NCATS-SM7270 and IMBIOC-1 provided a stronger protective effect on microglial cell survival than GSK2795039, which allowed us to assert the potential of those compounds as neuroprotective agents. Full article

A series of indolinone-based derivatives were designed and synthesized using the hybrid pharmacophoric design approach as cytotoxic kinase inhibitors. The cytotoxic effects of the designed molecules were tested against MCF-7 and HepG-2 cell lines. Compounds 9 and 20 were the most cytotoxic, with IC₅₀ values against HepG-2 and MCF-7 cells ranging from 2.53 to 7.54 µM. Additionally, compounds 9 and 20 were also found to be slightly more cytotoxic than indirubin with 2.2–2.7-fold higher cytotoxicity with HepG-2 cells. CDK-2 and CDK-4 kinase enzyme inhibition assay showed that compound 9 had a higher inhibitory effect (4.8-fold) than indirubin against CDK-2 and comparable inhibition against CDK-4. Moreover, compound 20 displayed nanomolar inhibitory action against both EGFR kinase and VFGFR-2 enzyme, which were around 8.8- and 5.4-fold higher than the IC₅₀ values of indirubin. Compounds 9 and 20 induced cell cycle arrest at the G₁ phase on HepG2 cells. The levels of the key apoptotic proteins assessed revealed elevated levels of the Bax/Bcl-2 ratio, which in turn initiated the caspase3/7 cascade that led to the activation of both intrinsic and extrinsic apoptotic pathways. The cell cycle inhibitory proteins p53 and p21 were significantly upregulated upon treatment with compounds 9 and 20. The docking results revealed that compound 9 exhibits stronger binding affinity to CDK-2 than indirubin, and compound 20 showed a similar binding mode to sorafenib with VEGFR-2. Full article

Cancer remains one of the leading causes of death globally, driving the need for effective therapies. Targeting cyclin-dependent kinase 2 (CDK2), a critical cell cycle regulator, is a promising approach for cancer treatment. This study developed a new group of 5-methylisatin derivatives with strong binding potential to CDK2. By combining the isatin core with various benzoylhydrazide substituents, the design process was guided by molecular docking, dynamic simulations, and ADMET analysis. Thirty-one derivatives were modelled, and a subset was synthesised and characterised for their physicochemical and spectroscopic properties. The analysis suggested that substitutions at R2 and R3 positions improved binding affinity, while modifications at R4 were less favourable. Hydrogen bonds with GLU81 and LEU83, along with hydrophobic interactions, were key to stabilising the complexes. A comparison with a reference molecule (RM) 3-((2,6-Dichlorobenzylidene)hydrazono)indolin-2-one, showing inhibitory activity similar to doxorubicin, revealed several advantages for the new derivatives. The multidimensional comparative analysis highlighted significant improvements in active site affinity, conformational stability, and fit. ADMET analysis confirmed comparable performance in most areas, with superior bioavailability observed in derivatives 1, 2a, 2b, 3h, 3b, and 3e. These results suggest that 5-methylisatin derivatives could be promising CDK2 inhibitors. Full article

This review probes the recent developments in stereoselective reactions within the area of sulfoxonium ylide chemistry since the early 2000s. An abundance of research has been applied to sulfoxonium ylide chemistry since its emergence in the early 1960s. There has been a continued effort since then with work in traditional areas, such as epoxidation, aziridination and cyclopropanation. Efforts have also been applied in novel areas, such as olefination and insertion reactions, to develop stereoselective methodologies using organocatalysis and transition metal catalysis. The growing research area of interrupted Johnson–Corey–Chaykovsky reactions is also described, whereby unexpected stereoselective cyclopropanation and epoxidation methodologies have been developed. In general, the most observed mechanistic pathway of sulfoxonium ylides is the formal cycloaddition: (2 + 1) (e.g., epoxides, cyclopropanes, aziridines), (3 + 1) (e.g., oxetanes, azetidines), (4 + 1) (e.g., indanones, indolines). This pathway involves the formation of a zwitterionic intermediate through nucleophilic addition of the carbanion to an electrophilic site. An intramolecular cyclization occurs, constructing the cyclic product. Insertion reactions of sulfoxonium ylides to X–H bonds (e.g., X = S, N or P) are also observed, whereby protonation of the carbanion is followed by a nucleophilic addition of X, to form the inserted product. Full article

A new approach to 1,2,5-trisubstituted 1H-indole-3-carboxylic esters has been developed and studied. The method begins with the preparation of imines from aldehyde and primary amine derivatives. Treatment of these imines with the K₂CO₃-derived anion from methyl 2-(2-fluoro-5-nitrophenyl)acetate or methyl 2-(5-cyano-2-fluorophenyl)acetate in DMF initiates a [3+2] cyclization by addition of the anion to the imine followed by ring closure of the adduct nitrogen to the activated aromatic moiety via an S_NAr process. Twenty-one examples are reported. Temperatures required for the conversion range from 90 to 95 °C for the nitro-activated substrates to 125 to 130 °C for the cyano-activated precursors. Though efficient and atom economical, limitations arise from steric hindrance in the reacting partners. The initial indoline formed is not observed but instead undergoes spontaneous air oxidation to the give the aromatic heterocycle. Imines from nonaromatic aldehydes and amines are also possible, but these give slightly lower yields of 1H-indoles and only react with the nitro-activated substrates. The results are presented with a discussion of the mechanism and the factors important to the success of the reaction. Full article

In this study, a set of spiro[5,8-methanoquinazoline-2,3′-indoline]-2′,4-dione derivatives 3a–p were synthesized starting from unsubstituted and N-methyl-substituted diendo- and diexo-2-aminonorbornene carboxamides, as well as various substituted isatins. The typical method involves a condensation reaction of alicyclic aminocarboxamide and isatin in the presence of a catalyst, using a solvent and an acceptable temperature. We developed a cost-effective and ecologically benign high-speed ball milling (HSBM), microwave irradiation (MW), and continuous flow (CF) technique to synthesize spiroquinazolinone molecule 3a. The structures of the synthesized compounds 3a–p were determined using 1D and 2D NMR spectroscopies. Furthermore, docking studies and absorption, distribution, metabolism, and toxicity (ADMET) predictions were used in this work. In agreement with the corresponding features found in the case of both the SARS-CoV-2 main protease (RCSB Protein Data Bank: 6LU7) and human mast cell tryptase (RCSB Protein Data Bank: 2ZA5) based on the estimated total energy and binding affinity, H bonds, and hydrophobicity in silico, compound 3d among our 3a–g, 3i–k, and 3m derivatives was found to be our top-rated compound. Full article

SBA-15 and organic ionic liquid were incorporated in a post-grafting technique for generating a bifunctional ionic liquid embedded mesoporous SBA-15. The prepared heterogeneous catalyst was employed for the first time to synthesize N-alkylated indoline-2,3-dione at mild conditions to afford excellent yields in a short reaction time. The synthesized DABCOIL@SBA-15 catalyst was meticulously characterized by various techniques, such as FT-IR, solid-state ¹³C NMR, solid-state ²⁹Si NMR, small-angle X-ray diffraction (XRD), and N₂ adsorption–desorption. Further, the morphological behavior of the catalyst was studied by SEM and TEM. The thermal stability and number of active sites were determined by thermogravimetric analysis (TGA). The Hammett equation was used to analyze the synergetic effect of the catalyst and substituent effects on the N-alkylated products of 5-substituted isatin derivatives, which resulted in a negative slope. This negative slope indicates a positive charge in the transition state. Notably, the DABCOIL@SBA-15 catalyst demonstrated its practicality by being reused for seven cycles with consistently high catalytic activity. Full article

Azide-containing compounds, organic azides, showcases a variety of reactivities, making them highly convenient and chameleonic intermediates. An indoline derivative has been proven to be of great significance in drug discovery due to its sp³-rich property. In this context, it is interesting to perform such vigorous azidation on medicinal-relevant indoles/indolines, resulting in the production of sp³-rich azidoindolines. The potential biological activity, in combination with the sp³-rich indoline bearing the azido moiety, makes azidoindolines an attractive synthetic target for medicinal and synthetic chemists. This review describes recent advances in the synthesis and application of azidoindolines: (1) iodine-mediated azidations, (2) metal-catalyzed azidations, (3) electrochemical azidations, (4) photochemical azidations, (5) azidation using a combination of an oxidant and an azide source, and (6) nucleophilic azidation. Full article

Cancer is one of the most important problems of modern societies. Recently, studies have reported the anticancer properties of rosiglitazone related to its ability to bind peroxisome proliferator receptor γ (PPARγ), which has various effects on cancer and can inhibit cell proliferation. In this study, we investigated the effect of new 4-thiazolidinone (4-TZD) hybrids Les-4369 and Les-3467 and their effect on reactive oxygen species (ROS) production, metabolic activity, lactate dehydrogenase (LDH) release, caspase-3 activity, and gene and protein expression in human foreskin fibroblast (BJ) cells and lung adenocarcinoma (A549) cells. The ROS production and caspase-3 activity were mainly increased in the micromolar concentrations of the studied compounds in both cell lines. Les-3467 and Les-4369 increased the mRNA expression of PPARG, P53 (tumor protein P53), and ATM (ATM serine/threonine kinase) in the BJ cells, while the mRNA expression of these genes (except PPARG) was mainly decreased in the A549 cells treated with both of the tested compounds. Our results indicate a decrease in the protein expression of AhR, PPARγ, and PARP-1 in the BJ cells exposed to 1 µM Les-3467 and Les-4369. In the A549 cells, the protein expression of AhR, PPARγ, and PARP-1 increased in the treatment with 1 µM Les-3467 and Les-4369. We have also shown the PPARγ modulatory properties of Les-3467 and Les-4369. However, both compounds prove weak anticancer properties evidenced by their action at high concentrations and non-selective effects against BJ and A549 cells. Full article

The endo-β-1,4-xylanase glycosyl hydrolase (GH11) decomposes the backbone of xylan into xylooligosaccharides or xylose. These enzymes are important for industrial applications in the production of biofuel, feed, food, and value-added materials. β-D-xylopyranose (XYP, also known as β-D-xylose) is the fundamental unit of the substrate xylan, and understanding its recognition is fundamental for the initial steps of GH11’s molecular mechanism. However, little is known about the recognition of a single XYP molecule by GH11. In this study, the crystal structures of GH11 from Thermoanaerobacterium saccharolyticum (TsaGH11) complexed with an XYP molecule were determined at a resolution of 1.7–1.9 Å. The XYP molecule binds to subsite −2 of the substrate-binding cleft. The XYP molecule is mainly stabilized by a π–π interaction with the conserved Trp36 residue. The O2 and O3 atoms of XYP are stabilized by hydrogen bond interactions with the hydroxyl groups of Tyr96 and Tyr192. The conformation of the thumb domain of TsaGH11 does not play a critical role in XYP binding, and XYP binding induces a shift in the thumb domain of TsaGH11 toward the XYP molecule. A structural comparison of TsaGH11 with other GH11 xylanases revealed that the XYP molecule forms π–π stacking with the center between the phenyl and indoline ring of Trp36, whereas the XYP molecule unit from xylobiose or xylotetraose forms π–π stacking with the indoline of Trp36, which indicates that the binding modes of the substrate and XYP differ. These structural results provide a greater understanding of the recognition of XYP by the GH11 family. Full article

This article describes the development of a nickel-catalyzed regio- and diastereoselective formal [3+2] cycloaddition between N-substituted indoles and donor–acceptor cyclopropanes to synthesize cyclopenta[b]indoles. Optimized reaction conditions provide the desired nitrogen-containing cycloadducts in up to 93% yield and dr 8.6:1 with complete regioselectivity. The substrate scope showed high tolerance to various substituted indoles and cyclopropanes, resulting in the synthesis of six new cyclopenta[b]indoles and the isolation of five derivatives previously reported in the literature. In addition, a mechanistic proposal for the reaction was studied through online reaction monitoring by ESI-MS, allowing for the identification of the reactive intermediates in the Ni(II) catalyzed process. X-ray crystallography confirmed the structure and relative endo stereochemistry of the products. This method enables the fast and efficient construction of fused indolines from readily accessible starting materials. Full article

Two previously described Brønsted acidic ionic liquids, 3,3′-(1,6-hexanediyl)bis(1-methyl)-1H-imidazolium hydrogen sulfate (Cat1) and 1,1′-(1,6-hexanediyl)bis(pyridinium) hydrogen sulfate (Cat2), were used as catalysts for the preparation of spiro[furan-2,3′-indoline]-3-carboxylate derivatives via a three-component reaction of anilines, isatins (N-alkyl-indoline-2,3-diones), and diethyl acetylenedicarboxylate, in high yields. The use of ultrasonic (US) irradiation led to the targeted products (1a–15a) in high yields ranging from 80% to 98%. Under the same conditions, the use of sulfuric acid and acetic acid as a Brønstedt catalyst did not yield the desired benchmark product 1a. Full article

Group Contribution (GC) methods to predict thermochemical properties are eminently important in chemical process design. Following our earlier work in which a Group Contribution (GC) model was presented to account for the gas-phase heat of formation of organic molecules which, for the first time, revealed chemical accuracy (1 kcal/mol or 4 kJ/mol), we here present Group Contribution parameters for a range of additional series of molecules allowing the application to a wider range of molecules whilst, mostly, retaining chemical accuracy. The new classes of molecules include amines, alkylesters, and various substituted benzenes, including t-butyl-benzenes, phenols, methoxybenzenes, anilines, benzaldehydes, and acetophenones, and finally furans and indoles/indolines. As in our previous works on this theme, again the critical selection of experimental data was crucial. Not meeting the criterion for chemical accuracy occurred when steric interactions such as nearest neighbour substituents on a benzene ring were present, something which does not fit with the characteristics of the Group Contribution method. We also report some cases for which the experimental value does not seem correct, but where both the G4 and GC model values agree well. In general, in line with accounts in the literature, the G4 method performs really well. Contrary to other related works, we have applied conformational averaging to obtain a slightly more realistic G4 result. Although the difference is generally only a few kJ/mol, this may still be relevant when attempting the development of a model with chemical accuracy, e.g., 4.2 kJ/mol. Full article