Nuclear Magnetic Resonance Spectral Data Research Articles

Expeditious chemical synthesis of xylomannans disproves the proposed antifreeze activities.

Cold-adapted species are able to generate cryoprotective proteins and glycoproteins to prevent freezing damage. The [→4)-β-D-Manp-(1→4)-β-D-Xylp-(1→] n xylomannan from the Alaska beetle Upis ceramboides was disclosed by Walters and co-workers in 2009 as the first glycan-based antifreeze agent, which was later reported to be found in diverse taxa. Here, we report the rapid synthesis of four types of xylomannans, including the proposed antifreeze xylomannan up to a 64-mer (Type I), the regioisomeric [→3)-β-D-Manp-(1→4)-β-D-Xylp-(1→] n 16-mer (Type II), the diastereomeric [→4)-β-L-Manp-(1→4)-β-D-Xylp-(1→] n 16-mer (Type III) and the block-wise [→4)-β-D-Manp-(1→] m [→4)-β-D-Xylp-(1→] n 32-mer (Type IV), by employing a strategic iterative exponential glycan growth (IEGG) process. The nuclear magnetic resonance spectral data of the alleged natural xylomannan are in accordance only to those of the block-wise Type IV glycan and none of these synthetic xylomannans has been found to be capable of inducing thermal hysteresis. These results disprove the previous reports about the natural occurrence of antifreeze xylomannans.

Carbohydrate NMR chemical shift prediction by GeqShift employing E(3) equivariant graph neural networks.

Carbohydrates, vital components of biological systems, are well-known for their structural diversity. Nuclear Magnetic Resonance (NMR) spectroscopy plays a crucial role in understanding their intricate molecular arrangements and is essential in assessing and verifying the molecular structure of organic molecules. An important part of this process is to predict the NMR chemical shift from the molecular structure. This work introduces a novel approach that leverages E(3) equivariant graph neural networks to predict carbohydrate NMR spectral data. Notably, our model achieves a substantial reduction in mean absolute error, up to threefold, compared to traditional models that rely solely on two-dimensional molecular structure. Even with limited data, the model excels, highlighting its robustness and generalization capabilities. The model is dubbed GeqShift (geometric equivariant shift) and uses equivariant graph self-attention layers to learn about NMR chemical shifts, in particular since stereochemical arrangements in carbohydrate molecules are characteristics of their structures.

Determination of the blending parameters of ternary blends containing a terpolymer as a component copolymer by multivariate analysis of NMR data

Heat-resistant ABS resin, an industrial polymer material, is generally prepared by mixing AN/MS bipolymer and/or AN/ST/MS terpolymer with the matrix of ABS resin, where AN, ST and MS denote acrylonitrile, styrene and α-methylstyrene, respectively. In order to predict the thermal properties of ABS resins, it is important to know which copolymers are blended and in what ratio. In this study, statistical structural analysis was performed on polymer blends consisting of AN/ST bipolymer, AN/MS bipolymer and AN/ST/MS terpolymer to predict blending parameters for heat-resistant ABS resin. Nuclear magnetic resonance (NMR) spectral data of the polymer blends were used as explanatory variables to determine the chemical composition and mole fraction of the component copolymers. Partial least-squares (PLS) regression and least absolute shrinkage and selection operator (LASSO) regression were used as the exploratory techniques. The use of 1H NMR spectral data showed poor prediction, probably because of low resolution due to the narrow spectral width. Accordingly, 13C NMR spectra, which have wider spectral widths, were used, resulting in the successful prediction of the blending parameters of the ternary blends containing a terpolymer as a component. It should be noted that it was not necessary to obtain the NMR spectra of all the polymer blends as the explanatory variables, i.e., linear combinations of the NMR spectra of the component copolymers were sufficient.

Targeting EGFR by Newer 1-(3,5-Bis((E)-4‑hydroxy-3-methoxystyryl)-1H-pyrazol-1-yl)-2-((substituted phenyl)amino)ethan-1-one Analogues for the Treatment of Cancer: Synthesis, In-vitro and In-silico Studies

Several curcumin analogues (C01-C03) were prepared in green solvent (water-glycerol; 2:1 v/v) with boric acid (10% mol solution in glycerol). All the compounds were characterized by spectroscopical techniques including infrared (IR), nuclear magnetic resonance (1H and 13C NMR) and mass spectral data. In accordance with the National Cancer Institute (NCI US) protocol, the curcumin analogues (C01-C03) were evaluated at 10 µM against 60 NCI cancer cell lines. One of the compounds (C01) was further evaluated in five dose assays. 1-(3,5-Bis((E)-4‑hydroxy-3-methoxystyryl)-1H-pyrazol-1-yl)-2-((4-chlorophenyl)amino)ethan-1-one (C01), exhibited a lethal effect on HL-60(TB) (PGI = 111.56) and MDA-MB-435 (PGI = 107.11). Additionally, the compound (C01) exhibited good inhibitory action against forty cancer cell lines with PGI 100 to >68 percent and moderate inhibitory action against fourteen cancer cell lines. The compound (C01) exhibited promising anticancer activity in five dose assays, with a mean GI50 value of 3.31 µM. Against the leukemia cell line SR, the compound showed the best response, with a GI50 value of 0.341 µM. All the curcumin analogous (C01-C03) demonstrated efficient binding against the AZD9291 binding site of EGFR with docking score of −6.849 to −7.444 kcal/mol. The compounds (C01-C03) demonstrated three H-bonds with the residue Met793, Lys728 and Asn842, and two halogen bonds with the residue Lys745 and Glu762. The MD simulation studies was performed against the curcumin analogue (C01) and compared with the standard drug gefitinib.

Method validation and characterization of stress degradation products of azelastine hydrochloride using LC-UV/PDA and LC-Q/TOF-MS studies.

Azelastine HCl is a second-generation H1 -receptor antagonist approved by the US Food and Drug Administration (US FDA) for treating seasonal allergic rhinitis and non-allergic vasomotor rhinitis. This study encompasses the validation of a liquid chromatography-ultra violet photo diode array (LC-UV/PDA) method for the drug and its extension to liquid chromatography/quadrupole time-of-flightmassspectrometry (LC-Q/TOF-MS) studies for identification and characterization of various stress degradation products of the drug. Stress degradation of azelastine HCl was undertaken under the International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) prescribed conditions of hydrolytic, photolytic, oxidative, and thermal stress. The degraded drug solutions were analyzed using Ultra Performance Liquid Chromatography (UPLC) employing a C18 (100 × 4.6mm; 2.6μ, Kinetex) column by isocratic elution. Detection wavelength was 241 nm. The degradation products were identified and characterized using UPLC-MS/TOF studies, and an attempt was made to isolate one of the degradation products by solvent extraction. The drug was found to significantly degrade under acidic/alkaline/neutral photolytic, oxidative, and alkaline hydrolytic conditions. Six degradation products (I-VI) were identified through LC-Q/TOF-MS studies that were adequately resolved from the drug with the developed UPLC method. All degradation products (I-VI) were ionized in the total ion chromatogram (TIC) in the LC-MS studies, and these were identified and characterized, and the degradation pathway of the drug was postulated. One of the oxidation products isolated from the degraded drug solution was characterized through differential scanning calorimetry, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance spectral data. Six degradation products generated from stress degradation studies on azelastine HCl were adequately resolved through LC-UV/PDA studies followed by method validation. These were successfully identified and characterized through LC-Q/TOF-MS studies, and the degradation pathways for the generation of these products from the drug have been postulated.

Eurycomanone from Eurycoma longifolia Jack upregulates neurotrophin-3 gene expression in retinal Müller cells in vitro.

Photoreceptor degeneration decreases light sensitivity and leads to vision loss and various retinal diseases. Neurotrophin-3, originating from Müller glial cells in the retina, plays a key role in protecting photoreceptors from damage induced by light or hypoxia. This neuroprotective approach is important because there are no established methods to regenerate lost photoreceptors. Dietary supplements are one of the useful methods for improving eye health. Eurycoma longifolia (E. longifolia) Jack, which is native to the tropical forest of Malaysia and other Southeast Asian countries, exhibits several medicinal properties. In the present study, we demonstrated that the water extract of E. longifolia roots enhanced neurotrophin-3 gene expression in primary rat Müller cells. Using a stepwise bioassay-guided fractionation and purification of E. longifolia root extracts, we isolated the active compound underlying neurotrophin-3 gene-enhancing activities. Mass spectrometry and nuclear magnetic resonance spectral data identified the compound as eurycomanone. This study provides evidence for the efficacy of E. longifolia and eurycomanone in enhancing neurotrophin-3 expression in Müller cells in vitro. Although the biological significance of this effect and its underlying mechanism remain to be elucidated, this study suggests that E. longifolia may be promising for improving eye health and must be further investigated.

Crystal Structure, Quantum Chemical, Hirshfeld Surface and Molecular Docking of Organic Molecular Salt: 2‐Amino‐5‐Chloropyridinium‐2,4‐Dihydroxybenzoate

AbstractAn organic molecular salt, 2‐amino‐5‐chloropyridinium‐2,4‐dihydroxybenzoate (ACP‐DHB) is synthesized by the slurry method followed by crystallization from methanol. The formation of molecular salt is initially confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectral data. Single crystal X‐ray diffraction (XRD) analysis shows that the crystal belongs to the monoclinic crystal system with space group, P21/n. Further, the supramolecular assembly involved the extensive network of N+−H···O− and N−H···O hydrogen bonds as well as C‐Cl···O halogen bond. Using UV‐Visible spectral data, the optical band gap is calculated and found to be 4.21 eV. Photoluminescence studies indicate the crystal has blue light emission properties. TG/DTA analysis shows that ACP‐DHB is thermally stable up to 162 °C. The quantum chemical calculations and natural bond analysis (NBO) are performed at B3LYP/6‐311G++ (d,p) basis set using Gaussian 09 software. The relative contributions of various intermolecular connections are discussed using Hirshfeld surface analysis and fingerprint plot illustration. The antibacterial and antifungal activity exhibits better inhibitory capacity against pathogens. Molecular docking revealed that ACP‐DHB efficiently binds with the 1UAG and 5KEE targets and has strong binding ability to the proteins. ADMET factors and Lipinski's rule of five are used to predict drug likeness property.

Formulation of multicomponent inclusion complex of cyclodextrin-amino acid with Chrysin: Physicochemical characterization, cell viability and apoptosis assessment in human primary glioblastoma cell line

Chrysin (CR) is a water-insoluble drug reported for different therapeutic effects. The microwave irradiation method was used in this study to create a multicomponent inclusion complex (CR-MC) containing CR (drug) and carrier hydroxyl propyl beta cyclodextrin (HP β CD) and L-arginine (LA). The prepared inclusion complex (CR-MC) was evaluated for dissolution study and results were compared with chrysin physical mixture (CR-PM). Further, the samples were assessed for infra-red (IR), nuclear magnetic resonance (NMR), differential scanning calorimeter (DSC), scanning electron microscope (SEM) and molecular docking. Finally, the cell viability, reactive oxygen species and flow cytometer studies were also assessed to check the potential of the prepared inclusion complex on the human primary glioblastoma cell line (U87-MG cell). The phase solubility findings revealed a stability constant (773 mol L−1) as well as a complexation efficiency of 0.027. The dissolution study displayed a significant increase in CR release from CR-MC (99.03 ± 0.39%) > CR-PM (70.58 ± 1.16%) > pure CR (35.29 ± 1.55%). NMR and IR spectral data revealed no interaction between CR and carriers. SEM and DSC study results revealed the conversion into amorphous form. The molecular docking results illustrated a high docking score, which supports the findings of complex formation. The cell viability, reactive oxygen species, and flow cytometry studies results showed enhanced activity from CR-MC against the tested human primary glioblastoma cell line. From the results it has been observed that chrysin solubility significantly increased after complexation and there in vitro activity also enhanced against cancer cell line.

Potential for Aedes aegypti Larval Control and Environmental Friendliness of the Compounds Containing 2-Methyl-3,4-dihydroquinazolin-4-one Heterocycle.

2-Methylquinazolin-4(3H)-one was prepared by the reaction of anthranilic acid, acetic anhydride, and ammonium acetate. The reaction of 2-methylquinazolin-4(3H)-one with N-aryl-2-chloroacetamides in acetone in the presence of potassium carbonate gave nine N-aryl-2-(2-methyl-4-oxoquinazolin-3(4H)-yl)acetamide compounds. The structures of these compounds were elucidated on the basis of their IR, 1H nuclear magnetic resonance (NMR), 13C NMR, and high-resolution mass spectrometry (HR-MS) spectral data. These synthesized compounds containing the 2-methyl-3,4-dihydroquinazolin-4-one moiety exhibited activity against Aedes aegypti mosquito larvae with LC50 values of 2.085-4.201 μg/mL after 72 h exposure, which is also confirmed using a quantitative structure-activity relationship (QSAR) model. Interestingly, these compounds did not exhibit toxicity to the nontarget organism Diplonychus rusticus. In silico molecular docking revealed acetylcholine binding protein (AChBP) and acetylcholinesterase (AChE) to be potential molecular targets. These data indicated the larvicidal potential and environmental friendliness of these N-aryl-2-(2-methyl-4-oxoquinazolin-3(4H)-yl)acetamide derivatives.

Isolation and Quantification of 2-O-Caffeoyl-hydroxycitric Acid, an Active Component in Hot Water Extracts of Coriander (Coriandrum sativum L.), Which Inhibits Degranulation of RBL-2H3 Cells

Objectives: Natural compounds that can effectively prevent and alleviate allergic symptoms, such as hay fever, are widely sought after from sources such as natural ingredients that can be ingested daily. Coriander extracts have been reported to show anti-allergic activity; however, hot water extracts have not been tested previously. Here, we found that a hot water extract of the aerial parts of coriander inhibited the degranulation of rat basophilic leukemia cell line RBL-2H3 cells and identified the active compounds. Methods: Chromatographic methods were used to isolate compounds from the hot water extract of coriander. The chemical structures were elucidated by analyses of high-resolution electrospray ionization mass spectrum and nuclear magnetic resonance spectral data. The degranulation activity of compounds was evaluated using the β-hexosaminidase release assay. Results: We analyzed the components to identify active compounds. 2 S,3 S-2- O-caffeoyl-hydroxycitric acid (1), and 2- O-caffeoyl-hydroxycitric acid 6′- O-methyl ester (2) were isolated from the hot water extract of coriander, and both compounds showed degranulation inhibitory activity in RBL-2H3 cells at a concentration below 2.5 mM. The content of compound 1 in the freeze-dried coriander powder was calculated to be 2.0% via HPLC quantification. Conclusions: Compound 1 was considered to be the primary active contributor in the hot water extract of coriander.

Identification and structural characterization of lactose adduct impurities in isosorbide dinitrate and hydralazine hydrochloride tablets by liquid chromatography‐mass spectrometry and nuclear magnetic resonance studies

AbstractIsosorbide dinitrate and hydralazine hydrochloride tablets are approved for the treatment of heart failure, prolonged hospitalization for heart failure, and enhanced patient‐reported functional status. It has been administered orally. Isosorbide dinitrate and hydralazine hydrochloride tablets contained two additional major unknown peaks (Degradation Product 1 and Degradation Product 2) in the stability studies (25°C/60% relative humidity and 40°C/75% relative humidity). These two unknown degradation peaks formed due to the heat (thermal) and humidity stress of hydralazine hydrochloride. Liquid chromatography separated these unknown degradant peaks. Initially, liquid chromatography‐mass spectrometry assessed the degradation pathways and mass of two degradants. Afterward, preparative‐liquid chromatography isolated the two major unknown degradation impurities formed under heat (thermal) and humidity stress conditions. Further, to confirm the structures, nuclear magnetic resonance spectroscopy evaluated these two degradants. The liquid chromatography‐mass spectrometry and nuclear magnetic resonance spectral data confirmed that the two degradation impurities are hydralazine lactosone ring‐opened adduct (Degradation Product 1) and s‐triazolo [3,4‐α] phthalazine (Degradation Product 2).

Synthesis of New 4′-(Substituted phenyl)spiro[indoline-3,3′-[1,2,4]triazolidine]-2,5′-diones as Antimicrobial, Antitubercular, and Antifungal Agents: An Insight into the ADME and Toxicity Prediction as well as in-silico Molecular Docking Studies

Spiro-compounds are a significant class of naturally occurring materials distinguished by their prominent biological characteristics. Spiro[indole-thiazolidines] analogues find an extensive application in the development of biologically active compounds. The synthesis of the 4′-(substitutedphenyl)spiro[indoline-3,3′-[1,2,4]triazolidine]-2,5′-diones (3a-d) described here was quick and efficient, and it produced excellent yields. The synthesis was carried out in a hydro-alcoholic (EtOH:H2O; 1:2 v/v) system with an addition of 30% mol of boric acid in glycerol. The structure of the prepared compounds was validated using infrared (IR), nuclear magnetic resonance (1H & 13C NMR) and mass spectral (GC-MS) data, followed by their antibacterial, antitubercular and antifungal activities. Among the series, 4́-(3-chloro-4-fluorophenyl)spiro[indoline-3,3́-[1,2,4]triazolidine]-2,5́-dione (3d) was found to be the most potent, with minimum inhibitory concentrations (MICs) values ranging from 4 to 8 µg/mL against both the gram positive (Bacillus subtilis and Staphylococcus aureus) as well as gram negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains. However, the compound 3d was found to have inconsequential activity against the mycobacterium strains (Mycobacterium tuberculosis H37Ra and M. bovis) and less activity against fungal strains (Aspergillus niger and Candida albicans). On the other hand 4́-(2-methoxyphenyl)spiro[indoline-3,3́-[1,2,4]triazolidine]-2,5́-dione (3c) displayed moderate but significant antifungal activity. The title compounds (3a-d) were further subjected to ADME and toxicity prediction as well as in-silico molecular docking studies against bacterial DNA gyrase (PDB ID: 6KZV). All the compounds (3a-d) followed the Lipinski's rule of five and were predicted as free from toxicities like immunotoxicity, mutagenicity and cytotoxicity and placed in Class IV category (300 < LD50 ≤ 2000). The docking score of the compound 3d was found to be −6.689 kcal/mol and demonstrated H-bond interactions with the residue Arg76 and Asp73 via water molecule.

Nematicidal Coumarins from Cnidium monnieri Fruits and Angelica dahurica Roots and Their Physiological Effect on Pine Wood Nematode (Bursaphelenchus xylophilus).

Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a major pathogen of pine wilt disease (PWD), which is a devastating disease affecting pine trees. Eco-friendly plant-derived nematicides against PWN have been considered as promising alternatives to control PWD. In this study, the ethyl acetate extracts of Cnidium monnieri fruits and Angelica dahurica roots were confirmed to have significant nematicidal activity against PWN. Through bioassay-guided fractionations, eight nematicidal coumarins against PWN were separately isolated from the ethyl acetate extracts of C. monnieri fruits and A. dahurica roots, and they were identified to be osthol (Compound 1), xanthotoxin (Compound 2), cindimine (Compound 3), isopimpinellin (Compound 4), marmesin (Compound 5), isoimperatorin (Compound 6), imperatorin (Compound 7), and bergapten (Compound 8) by mass and nuclear magnetic resonance (NMR) spectral data analysis. Coumarins 1-8 were all determined to have inhibitory effects on the egg hatching, feeding ability, and reproduction of PWN. Moreover, all eight nematicidal coumarins could inhibit the acetylcholinesterase (AChE) and Ca2+ ATPase of PWN. Cindimine 3 from C. monnieri fruits showed the strongest nematicidal activity against PWN, with an LC50 value of 64 μM at 72 h, and the highest inhibitory effect on PWN vitality. In addition, bioassays on PWN pathogenicity demonstrated that the eight nematicidal coumarins could effectively relieve the wilt symptoms of black pine seedlings infected by PWN. The research identified several potent botanical nematicidal coumarins for use against PWN, which could contribute to the development of greener nematicides for PWD control.

Optimization of the synthesis, in silico ADME/Tox profiling studies, and evaluation of the antimalarial activity of (7-chloroquinolin-4-ylthio)alkylbenzoate derivatives

Optimized reaction conditions are developed to obtain a series of [(7-chloroquinolin-4-yl)sulfanyl] alcohol derivatives as intermediates to prepare a range of (7-chloroquinolin-4-ylthio) alkylbenzoate derivatives. The structures of all the synthesized compounds are confirmed from their infrared and nuclear magnetic resonance spectral data, and by elemental analysis. In silico ADME/Tox profiling studies of the synthesized molecules are undertaken, and the potential antimalarial activity of the products is determined. In vitro, all the prepared compounds significantly reduce heme crystallization with IC50 values of &lt; 10 µM. In vivo, the reduction in parasitemia levels and survival time increases are marginal.

HPLC separation, synthesis, isolation and characterization of process related and degradation impurities in larotaxel including method development and validation

In the synthesis of larotaxel, a new-generation toxoid, eleven related impurities were detected. In this study, Impurity-I, II, III, IV, VII, IX, X and XI were synthesized, and Impurity-VI, VIII were isolated with the help of preparative high-performance liquid chromatography (HPLC). The structures of all impurities were characterized using high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectral data, and the possible origins of them were explained. Furthermore, a sensitive and accurate HPLC method was developed for the determination of larotaxel and its eleven impurities. The method was validated to fulfill the requirements of the International Conference on Harmonisation (ICH) guidelines, including specificity, sensitivity, precision, accuracy, linearity, and robustness. The validated method can be applied for routine quality control analysis of larotaxel.

White analytical chemistry-driven stability-indicating concomitant chromatographic estimation of thiocolchicoside and aceclofenac using response surface analysis and red green blue model.

White analytical chemistry is a novel concept for the assessment of analytical methods on basis of its validation efficiency, greenness power and economical efficiency. White analytical chemistry-driven stability indicating chromatographic method has been developed for the concomitant analysis of thiocolchicoside and aceclofenac. The proposed chromatographic method has been developed using a safe and environmental-friendly organic solvent for the concomitant stability study of thiocolchicoside and aceclofenac. The analytical risk assessment was carried out for the identification of high-risk analytical risk factors and analytical method performance attributes. The mixture design was applied for the design of experiments-based response surface modelling of high-risk analytical risk factors and analytical method performance attributes. The degradation products were isolated and characterized using infra-red, nuclear magnetic resonance and mass spectral data. The proposed method was compared for its validation efficiency, greenness power and cost-efficiency with published chromatographic methods using the red, green and blue models. The white score of the proposed and reported method was calculated by averaging the red, blue and green scores of the methods. The proposed method was found to be robust, green and economical for the concomitant stability study of thiocolchicoside and aceclofenac. This article is protected by copyright. All rights reserved.

Conditional Molecular Generation Net Enables Automated Structure Elucidation Based on 13C NMR Spectra and Prior Knowledge.

Structure elucidation of unknown compounds based on nuclear magnetic resonance (NMR) remains a challenging problem in both synthetic organic and natural product chemistry. Library matching has been an efficient method to assist structure elucidation. However, it is limited by the coverage of libraries. In addition, prior knowledge such as molecular fragments is neglected. To solve the problem, we propose a conditional molecular generation net (CMGNet) to allow input of multiple sources of information. CMGNet not only uses 13C NMR spectrum data as input but molecular formulas and fragments of molecules are also employed as input conditions. Our model applies large-scale pretraining for molecular understanding and fine-tuning on two NMR spectral data sets of different granularity levels to accommodate structure elucidation tasks. CMGNet generates structures based on 13C NMR data, molecular formula, and fragment information, with a recovery rate of 94.17% in the top 10 recommendations. In addition, the generative model performed well in the generation of various classes of compounds and in the structural revision task. CMGNet has a deep understanding of molecular connectivities from 13C NMR, molecular formula, and fragments, paving the way for a new paradigm of deep learning-assisted inverse problem-solving.

Bioactive Compounds from Mimosa pudica Leaves Extract with Their α- glucosidase and Protein Tyrosine Phosphatase 1B Inhibitory Activities in vitro and in silico Approaches

&lt;p&gt;Background: Mimosa pudica Linn has been used in traditional medicine to support the treatment of type 2 diabetes. In the present study, we aimed to isolate and evaluate &amp;#945;-glucosidase and Protein Tyrosine Phosphatase 1B (PTP1B) inhibitory activities of bioactive compounds from Mimosa pudica’s leaf extract. &lt;p&gt; Methods: Mimosa pudica leaves were extracted with 80% of ethanol. Bioactive compounds were isolated using a column chromatographic technique and elucidated the structure based on the nuclear magnetic resonance and electrospray ionization mass spectrometry spectral data. The &amp;#945;- glucosidase and PTP1B inhibitory activities of the isolated compounds were evaluated using pnitrophenyl phosphate and p-nitrophenyl-&amp;#945;-D-glucopyranoside as a substrate, respectively. Molecular docking and molecular dynamics are used to study the interaction between isolated compounds and proteins. Lipinski’s rule of five was used to evaluate the drug-like properties of isolated compounds. Predict pharmacokinetic parameters were evaluated using the pkCSM tool. &lt;p&gt; Results: Protocatechuic acid and syringic acid were isolated and identified using spectroscopic methods. Protocatechuic acid and syringic acid considerably inhibited &amp;#945;-glucosidase enzyme at IC&lt;sub&gt;50&lt;/sub&gt; values of 416.17 ± 9.41 μM and 490.78 ± 9.28 μM, respectively. Furthermore, protocatechuic acid and syringic acid expressed strong PTP1B inhibitory activity at IC&lt;sub&gt;50&lt;/sub&gt; values of 248.83 ± 7.66 μM and 450.31 ± 7.77 μM, respectively. Molecular docking and molecular dynamics results showed the interactions of protocatechuic acid and syringic acid with amino acids of PTP1B and &amp;#945;-glucosidase enzyme. Lipinski’s rule of five and absorption, distribution, metabolism, excretion, and toxicity studies predicted that protocatechuic acid and syringic acid have drug-likeness properties. In molecular docking simulation, protocatechuic acid and syringic acid gave relatively negative free binding energies and interacted with many amino acids in the active sites of PTP1B and &amp;#945;-glucosidase. The molecular dynamics simulation results of the complexes were also relatively stable. &lt;p&gt; Conclusion: Our results showed that protocatechuic and syringic acids could be promising compounds for type 2 diabetes treatment.&lt;/p&gt;

A greener approach of synthesis of new 2-chloro-1,3,2-diazaphosphinin-4-one-2-oxide derivatives

In this work, we describe a novel, easy and green method for the synthesis of diazaphosphinine derivatives. The new diazaphosphinines were prepared by condensation of phosphorus oxychloride with the corresponding benzamides under reflux in acetone with moderate to good yields. The structures of the new compounds were confirmed on the basis of their infrared and nuclear magnetic resonance spectral data (1H, 13C, and 31P), MS, and elemental analysis.

Novel self curable phosphorus- and spiro phosphorus-based maleimides: synthesis, characterization, cure behavior and thermal properties

Novel phosphorus- and spiro phosphorus-based maleimides such as tris[4-(2,5-dioxopyrrol-1-yl)phenyl] phosphite (TDPPI), tris[4-(2,5-dioxopyrrol-1-yl)phenyl] phosphate (TDPPA), 3,9-di[4-(2,5-dioxopyrrol-1-yl)phenoxy]-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (TDU), and 3,9-di[4-(2,5-dioxopyrrol-1-yl)phenoxy]-2,4,8,10-tetraoxa-3λ5,9λ5-diphosphaspiro[5.5]undecane 3,9-dioxide (TDUD) have been synthesized. The structural characterization of the synthesized maleimides was performed using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and 1H, 13C and 31P nuclear magnetic resonance spectral data. Melting behavior and heat changes during the materials’ physical and chemical changes as a temperature function were studied using differential scanning calorimetry (DSC). Mass loss rate, residual mass and the gases evolved during thermal degradation were examined using a thermogravimetric (TG) analyzer coupled with FTIR. All four maleimides having a low enthalpy of curing and high char residue (about 50 wt%) display better thermal stability than the parent N-(4-hydroxy phenyl)maleimide (N4HPMI). This was owing to the presence of phosphorus or spiro phosphorus moiety in conjunction with the maleimide unit. The combined impact of phosphorus and maleimide units makes the materials suitable for high-performance applications.