13C NMR Data Research Articles

Synthesis and biological evaluation of amide derivatives of the quinazoline tethered (pyridyl)-1,2,4-thiadiazoles as anticancer agents

A new library of amide derivatives of quinazoline-1, 2, 4-thiadiazoles (12a–j) has been synthesized and its structures were confirmed by 1H NMR, 13C NMR and mass spectral data. The in-vitro anticancer activity of all the newly derived compounds (12a–j) was assessed for their preliminary anticancer applications toward different cancer cell lines including MCF-7 (breast cancer), A549 (lung cancer), Colo-205 (colon cancer) and A2780 (ovarian cancer) by employing the MTT method using Etoposide as a positive control. From the table the results indicated that most of the tested compounds displayed good to moderate activity compared to etoposide. Among the twelve compounds synthesized, compounds 12a, 12b, 12c, 12d, 12e and 12f possessed more potent activity than the positive control. Particularly, compound 12a displayed superior anticancer activity.

Changes in the macro and nano-structure of paper during moisture cycling

Hygroexpansion, CP/MAS 13C-NMR, WAXS and SAXS measurements were carried out on sheets made from four different commercial pulps of varying lignin content. Non-directional laboratory sheets were made at different press levels from the pulps following different degrees of beating. The sheets were dried both freely and with restraints. Measurements were made on sheets before and after moisture cycling to determine hygroexpansion coefficients, changes in cellulose average lateral fibril dimensions and average cellulose crystallite sizes, with the aim of understanding macroscale and nanoscale changes as the result of moisture cycling. Within the sheets consistent and statistically significant structural changes were observed on both macro and nanoscale. On the macroscale, moisture cycling consistently induced irreversible shrinkage in sheets dried with restraints, but less so in the case of sheets dried freely. The hygroexpansion coefficients were typically higher for freely dried sheets compared with sheets dried with constraints. On the nanoscale, moisture cycling consistently caused an increase in the average crystallite sizes (WAXS) and the average lateral fibril dimensions (CP/MAS 13C-NMR), though the latter occurred with poor statistical significance. These changes were interpreted as an increase in the degree of order in the cellulose fibril interior/cellulose crystallite. There were no profound differences in the nanoscale changes observed for sheets dried with restraints and for sheets dried freely. Changes in the fibre wall nanostructure were of similar magnitudes when comparing results from freely dried low grammage sheets (less abundant inter-fibre joints) with freely dried sheets of higher grammage (more abundant inter-fibre joints). No obvious correlations were found between the macroscale and nanoscale measurements. The proposed explanation for this was that the nanoscale structural changes occurred similarly throughout the entirety of the fibre wall, independent of the proximity to an inter-fibre joint, and that the nanoscale structural changes were mainly the result of water penetrating into the interior of cellulose fibril aggregates. By using the same fibril model for evaluation of CP/MAS 13C-NMR and WAXS data, good-to-reasonable agreement were found for estimates of the degree of cellulose crystallinity.

Design, Synthesis and Biological Evaluation of Aryl Benzimidazole-Pyridones as Cytotoxic Agents

A new library of Aryl Benzimidazole-Pyridones (9a–j) has been synthesized, their structures were determined by 1HNMR,13CNMR and mass spectral data. Further, these compounds explored for their anticancer application on four human cancer cell lines such as human prostate cancer cell line (PC3), lung cancer (A549), breast cancer (MCF-7) and human ovarian cancer (A2780) by employing MTT assay and results were compared with known anticancer agent asetoposide. All these compounds displayed remarkable cytotoxic activity. Among them, five compounds 9a, 9b, 9c, 9h and 9i displayed more potent activity. All compounds exhibited a discerning cytotoxic effect on cancer cells while not affecting normal Vero cells (IC50 = >22 µM), so providing justification for the strategic design approach employed in the development of a targeted anticancer drug.

Nitrogenous compounds from Aesculus wilsonii seeds

Eight nitrogenous compounds including five undescribed ones, aeswilnitrousol A (1), aeswilnitrousosides BD (2–4), and 6-(2-hydroxy-3-methylbutylamino)-8-oxoadenine (5) were isolated from the seeds of Aesculus wilsonii. Their structures and absolute configurations were established based on spectroscopic determination, calculated electronic circular dichroism (ECD) analysis, as well as chemical reaction methods. Among the three known compounds, 7 and 8 were obtained from the Aesculus genus for the first time, and 6 was gained from this plant initially. The 13C NMR data of 7 and 8 were reported for the first time. Moreover, the inhibitory effect of all the isolates against LPS-induced nitric oxide production in RAW264.7 macrophages was evaluated. As a result, compounds 2 and 8 exhibited anti-inflammatory activity in a concentration-dependent manner at 10, 25, and 50 μM.

Synthesis, electropolymerization, and optoelectronic properties of carbazole containing imidazolium based ionic liquid

Herein, we report a prominent initial step toward the rational design of a carbazole-based ionic liquid. Firstly, the novel ionic liquid-based monomer of 1,3-bis[6-(9 H-carbazol-9-yl)-1H-imidazol-3-ium bromide] (coded as M4) salt has been synthesized 9{[6-(1 H-imidazol-1-yl) hexyl]-9 H-carbazole} which was prepared by the addition reaction of imidazole and N-(6-bromohexyl)carbazole, proceeded by connecting N-(6-bromohexyl) carbazole as precursor compound. The structural properties of the M4 have been determined by 1H NMR, 13C NMR, FT-IR, and MS spectral data. The corresponding polymer film (P4) has been synthesized electrochemically on the ITO electrode. The redox behaviors of the resulting polymer have been investigated in detail via cyclic voltammetry and spectroelectrochemistry techniques. The conducting polymer film has exhibited a multi-electrochromic behavior with color changes from transparent, to greenish-yellow and then to blue-green. Moreover, the polymer film has exhibited satisfactory optical contrast, high coloration efficiency, and fast switching time, which made them potential candidates in high-tech applications.

Synthesis and characterization A derivative of levofloxacin and a study of its bacteriostatic activity

This study includes two newly synthesized prodrugs of Levofloxacin derivatives mono and dipeptide H2, where was the Synthesized monoPeptide as Levofloxacin-Histadine (L-H), as well as dipeptide H6 as Synthesis of diPeptide (phenylalanine- levofloxacin (GPA-L), using a Levofloxacin substituted. Spectroscopic data were studied for two derivative compounds H2 and H6 and reactivity indices were characterized using techniques FT-IR, 1H-NMR, and 13C-NMR. All the newly produced derivative compounds H2 and H6 have FT-IR spectra that share similarities in certain fingerprint-like bands and other bands. The essential functional group vibration bands. In the DMSO-d6 solvent, the compound H2, and H6 of 1H NMR spectra were studied, Typically, the fitted intensity ratio of the observed compound 1H NMR spectra gives, and the expected signals. The DMSO-d6 solvent was employed to record the 13C NMR spectra of levofloxacin derivatives H2 and H6. portrayed the 13C NMR spectra of generated compounds H1 through H6, comprised of the 13C NMR data. where done Further confirmation of the properties of the developed molecule emerged from 13C-NMR spectra. 1
 The bioactivity was studied for two derivative compounds H2 and H6 against three gram-positive and three gram-negative Bacteria. The mono and dipeptide prodrugs that are derivatives of levofloxacin have appeared to have excellent results against these Bacteria. Antibiotic susceptibility experimental findings revealed that various bacteria had taken different approaches to the tested drugs. most bacteria isolated in gram-positive and gram-negative demonstrated severe sensitivity to the generated compounds (H2 and H6). The spectral results in the FT-IR analyses as well as the nuclear magnetic resonance studies showed the high validity of the compounds formed ( H2 and H6) interaction, as well as the biological results showed a clear positive in killing bacteria of the type of Gram-negative and Gram-Positive.

Inhibition mechanism of rice glutelin on extruded starch digestion: From the structural properties of starch and enzyme activity

To increase the anti-digestion ability of extruded rice starch (ERS), the influence of rice glutelin (RG) on digestive and structural characteristics of ERS were investigated. The resistant starch content increased from 4.49 % to 18.08 % as the RG content increased, while the digestion rate and digestion velocity constant were reduced by the incorporation of RG. Morphological observations showed that ERS was adhered and encapsulated by RG, and the specific area of starch granules were decreased after the addition of RG. The results of XRD and FTIR suggested that the long-range and short-range orders of ERS were improved due to the complexation with RG. The thickness of crystalline of ERS was increased while its amorphous region thickness was reduced by the supplementation with RG. The 1H NMR and 13C NMR data revealed that the branching degree and double helix content of ERS was increased by 46.24 % and 52.67 % when RG content reached to 12 %. Additionally, the addition of RG altered the molecular weight and chain length distribution of ERS. The α-amylase activity and glucoamylase activity was inhibited by RG. These results could provide a valuable basis for the application of RG in extruded rice starchy foods with lower glycemic index.

Synthesis and Evaluation of Anticancer Potential of Novel Benzopyran Derivatives Using MTT and in vitro Scratch Assays

Evidence over benzopyrans and azomethines high anticancer potential, intended present study to carry out the synthesis, characterization and anticancer activity of some new benzopyrans derivatives (NBD). Study involved synthesis of N'-(substituted benzylidene)-2-(2-oxo-2H-benzopyran-4-yloxy)acetohydrazide (2a-d) by hydrazination of substituted benzopyran ester (1). The structures of all the synthesized benzopyran derivatives (NBD 2a-d) were elucidated based on the IR, 1H NMR, 13C NMR and mass spectral data. The NBD 2a-d were further investigated for their cell viability (toxicity analysis) against HEK-293 and anticancer potential against MCF-7 cancer cell lines using MTT assay and in vitro scratch assay. Present study revealed that NBD 2a-d structures were in agreement with their IR, NMR and mass spectrometric characterization data. The cell viability study, MTT and in vitro scratch assay of NBD 2a-d, revealed compound 2d to exhibit highest anticancer activity and safety when compared with standard (irinotecan). Present study concludes NBD 2d to possess high anticancer potential and proven to be safer when compared with irinotecan, however further studies are needed to establish its clinical significance.

Green and Regioselective Alkylation of Dihydropyrimidinthiones through Michael Addition

Abstract: Dihydropyrimidines are one of the most important heterocyclic ring systems having a serious place in medicinal and organic synthesis. In this paper, a new series of dihydropyrimidines consisting of sulfur atoms were synthesized using inorganic base K2CO3 and TBAB as an organic salt to make high polarity in reaction media. Interestingly, different 3,4-dihydropyrimidin-2(1H)-thiones reacted smoothly with various acrylic esters to afford adducts via highly regioselective N3-Michael addition reaction was carried out at 100oC in 12 h. result: Unfortunately, the reaction failed with fumaric esters owing steric effects. Avoiding organic solvents during this reaction effectively led to the development of an economic approach. Structures of the new compounds were established on the basis of 1H NMR, 13C NMR, and IR spectral data.

Quantitation of olefins in sustainable aviation fuel intermediates using principal component analysis coupled with vacuum ultraviolet spectroscopy

Olefins, a common intermediate from biomass conversion processes, are undesirable in jet fuel because of their poor thermal stability. This paper presents an approach for olefin quantitation using 2D gas chromatography coupled with vacuum ultraviolet spectroscopy. Principal component analysis was used to reduce the dimensionality of the spectroscopic data from a highly olefinic fuel intermediate. A principal component template was created that enabled olefin quantitation, which was compared to the existing GCxGC-VUV approach from the literature. The principal component method was able to identify and quantify trace amounts of cyclodienes, which were present at only 0.01 wt% in the fuel sample. The principal component approach also identifies species that fall outside of the GCxGC template. For instance, quantitation with the literature method resulted in an olefin concentration of 0.95 times that of the principal component method due to olefins falling outside of the expected GCxGC regions. The principal component results were compared with 13C and 1H NMR data, which confirmed that the fuel had a high concentration of olefins and alkanes with little aromatic content.

Regio- and chemoselective synthesis of polyaryl flavones by combination of C-O/C-H activation and Suzuki-Miyaura cross coupling reactions

The first regioselective ruthenium-catalyzed arylation of flavone-derived compounds is reported. Exploring the molecular structure-reactivity different 5-,5,8-, 5,7-, 5,6- and 5,7,8-aryl substituted flavones were prepared through Ru-, Ni- and Pd-catalyzed coupling reactions with aryl boronic species under regio- and chemoselective approach in moderate to excellent yields. The obtained derivatives were thoroughly characterized by spectroscopic techniques, such as 1H NMR, 13C NMR and HRMS data. The convenient availability of starting natural product chrysin confers facility to the employed reactions which products may find application in pharmaceutical and material science areas.

Antimicrobial activity of guanidine-based terpolymers: Synthesis, Spectroscopy (FT-IR, 1H, and 13C NMR), Quantum chemical investigation, and molecular docking

This study presents a comprehensive assessment of the antimicrobial efficacy of a Guanidine-Based Terpolymer (DGF) utilizing a blend of experimental and theoretical methodologies. Structural insights were derived from experimental analyses, such as FT-IR, 1H, and 13C NMR data, along with mass spectra. Employing Density Functional Theory (DFT) at the DFT/B3LYP/aug-cc-pVDZ level of theory, accurate predictions of drug molecule properties including reactivity and stability were achieved. Results from the antimicrobial screening suggested that the studied compound has significant antimicrobial activity, with the highest effectiveness against Candida albicans (26 mm/ml), followed by Staphylococcus aureus (22 mm/ml), Aspergillus niger (22 mm/ml), and Escherichia coli (20 mm/ml). Substantially, from the pharmacokinetics, the studied compound against Staphylococcus aureus was evaluated, revealing favorable drug toxicity potentials with low values for Hepatotoxicity (P = 0.75), Carcinogenicity (P = 0.56), Immunotoxicity (P = 0.99), Mutagenicity (P = 0.56), and Cytotoxicity (P = 0.61), indicative of inactivity. Metabolism studies identified notable inhibitors, including CYP2C19 (++), CYP2C9 (+); CYP2D6 (++), and CYP3A4 (++). Additionally, molecular docking on fungal (C. albicans and A. niger) and bacterial (E. coli and S. aureus) proteins showcased robust binding affinities between the DGF ligand and the proteins tested against. Notably, DGF exhibited superior efficacy against C. albicans (-7.5 kcal/mol) compared to amphotericin B (-6.8 kcal/mol), while effectiveness against A. niger (-7.4 kcal/mol) was slightly lower than the standard drug (-9.6 kcal/mol). In bacterial investigations, DGF demonstrated heightened efficacy against S. aureus with a binding affinity of -8.1 kcal/mol and three conventional hydrogen bonds. Contrastingly, its standard drug, Penicillin, displayed a lower binding affinity (-7.4 kcal/mol) and formed three conventional hydrogen bonds. This analysis, consistent with prior antimicrobial studies, and proposes DGF as a potential antibacterial agent, especially against Gram-positive bacteria like Staphylococcus species, attributed to its presence of conventional hydrogen bonds and high binding affinity in interactions with S. aureus.

Synthesis and biological evaluation of gallic acid esters as phagocyte oxidative burst inhibitors

Several degenerative diseases, including cancer, are caused by oxidative stress, which is caused by the overproduction and accumulation of free radicals. The purpose of the study was to synthesize gallic acid (GA or 3,4,5-trihydroxybenzoic acid) esters and evaluate their anti-inflammatory potential through the inhibition of reactive oxygen species (ROS). The compounds methyl gallate (2), sec-butyl gallate (3), ethyl gallate (4), isopropyl gallate (5), 2-methoxyethyl gallate (6), 4-methoxybutyl gallate (7), 2-methylbutyl gallate (8) and pentan-3-yl gallate (9) were synthesized. 1H NMR, MS and IR data are reported for compounds 2-9, and 13C NMR data for compounds 2, 3, 5, and 6. The molecular formulae of compounds 3 and 7-9 were established by HREI-MS spectroscopic data. All the synthesized compounds were tested for their anti-inflammatory and cytotoxic activities by chemiluminescence and MTT cytotoxicity assay respectively. The results revealed the anti-inflammatory potential of compounds 2-8 with an IC50 range between (13.3 – 54.3 µM) as compared to the standard anti-inflammatory drug, Ibuprofen (IC50 = 54.3 ± 9.2 μM). The most potent inhibitors were found to be compound 3 (ROS IC50 = 15.0 ± 6.6 µM) and compound 7 (ROS IC50 = 13.3 ± 0.8 µM). All compounds were found to be non-cytotoxic in the NIH-3T3 fibroblast cell line. Compounds 3, 7- 9 were identified as new compounds.

Synthesis, Characterization and in vitro Anticancer Activity of New Quinoline Analogues against Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) developed from mucosal lining of oral cavity is ranked as 6th most common cancer worldwide. Adverse effects of available anticancer agents intended present work to carry out the synthesis, characterization and evaluation of new quinoline analogues (NQA) against OSCC cell lines. In present study, substituted quinoline (1) was treated with ethyl chloroacetate to offer ester derivative (2), which on treatment with hydrazine hydrate yielded hydrazide derivative (3), which was cyclized into oxadiazole derivative (4) when cyclized with 4-methoxy benzoic acid. Characterization of molecular structures of synthesized NQAs was done based on the FTIR, 1H NMR, 13C NMR and mass spectrometric data. The characterized NQAs were investigated for their anticancer potential. The anticancer studies involved antiproliferation study (IC50 determination) against OSCC cell lines (CAL-27), followed by cell cycle analysis. The results of antiproliferation study of NQAs revealed that among all, NQA 3 exhibited lowest IC50 (3.26 μg/mL). Also, the results of cell cycle analysis of all NQA revealed that all NQAs caused cancer cells arrest in ‘S’ phase. The high anticancer activity of NQA 3 and ability of all the NQAs to cause CAL-27 cells arrest in ‘s’ phase supports their potential application in OSCC treatment. However, the synthesized NQAs must be additionally investigated for the in vivo and clinical studies.

In vitro Antidiabetic and Anticancer Activity of Some Novel Diazenyl Benzene Sulphonamide Derivatives

A series of novel 2-[(5-phenyl-1,3,4-thiadiazole-2-imino)substituted benzene]diazenyl benzene sulphonamide derivatives (VII)6-10 weresynthesized and FT-IR, 1H NMR, 13C NMR and GC-MS spectral data were used to investigate the structures of the synthesized sulphonamide derivatives. The antioxidant activity of 2-[(5-phenyl-1,3,4-thiadiazole-2-imino)substituted benzene]diazenyl benzene sulphonamide derivatives (VII)6-10 was done using DPPH technique. Compounds (VII)7 and (VII)9 displayed excellent antioxidant activity when compared to standard ascorbic acid. The in vitro antidiabetic activity on α-amylase and α-glucosidase studies indicated compound (VII)7 as promising inhibitor of α-amylase and α-glucosidase. The cytotoxic activity of the synthesized compound (VII)9 was tested against human colon (HCT-116), lung (A549), breast (MCF-7) cancer cell lines and fibroblast (L929) normal mouse lines. The results showed that compound (VII)9 has good cytotoxic activity.

2,2′-Trisulfanediyldibenzoyl Chloride

The X-ray structure of the title compound, formed at low conversion in the reaction of thiosalicylic acid with thionyl chloride, has been determined. The acid chloride groups are oriented to permit an attractive non-bonding O…S interaction. Mechanisms are suggested for the formation of this unexpected product. 1H and 13C NMR data are also reported for the first time for the major reaction product, 2-mercaptobenzoyl chloride.

Novel Thiazolactone Derivatives: Synthesis and Quantum Chemical Study

In this research, 15 novel derivatives of the thiazolactone skeleton were synthesized using the Erlenmeyer–Plöchl reaction procedure. Glycine, alanine and leucine amino acids were used to make dithiocarbamate precursor by reacting amino acids with carbon disulfide and benzyl chloride. Obtained benzyl dithiocarbamate underwent thiazolactone formation in the presence of acetic anhydride and then condensed with arylglyoxals as condensing carbonyl group source. Products were characterized using their spectroscopic IR, 1H NMR, and 13C NMR data. In continuation, computational chemistry methods were used to get some information about the products such as structural characteristics, charge distribution, 1H NMR and UV-visible spectra. Results showed that the calculated chemical shifts are in good agreement with experimentally recorded ones. The B3LYP density functional method in conjunction with the 6-311++G(d,p) basis set was used for all calculations.

Phytoconstituents of two Gleditsia L. species and cytotoxic activity of the isolated curcumin analogues

Methanolic extracts of Gleditsia triacanthos L. fruits and Gleditsia caspica Desf. leaves yielded two mono-carbonyl curcumin analogues; (1E,4E)-1,5-bis(4-hydroxy-3-methoxyphenyl)penta-1,4-dien-3-one [1], (1E,4E)-1,5-bis(4-hydroxyphenyl)penta-1,4-dien-3-one [2], in addition to β-sitosterol [3], apigenin [4], quercetin-3`-O-methyl ether [5], rutin [6], quercetin [7], naringenin [8], eriodictyol [9], vitexin [10], isovitexin [11], gleditsin A [12]. The isolation of these compounds was reported here for the first time from the named plants. The separation and identification of curcumin analogues from genus Gleditsia in addition to 13C NMR data of compound 2 were reported here for the first time. Compounds 1 and 2 were assayed in two hepatic cancer cells; HepG-2 and Huh-7. Compound 1 showed high cytotoxic activity against HepG-2 with an IC50 value of 14.39 µM, compared with the standard, IC50 = 12.44 μM.

Synergistic Combination of NAPROC-13 and NMR 13C DFT Calculations: A Powerful Approach for Revising the Structure of Natural Products.

This article describes the structure revision of nine triterpenoids that have been reported corresponding to the same 13C NMR data set. In addition, 13C NMR calculation shows that some chemical shift assignments must be swapped. Our analysis improves the fit between the experimental and calculated data. Correcting misassigned structures and correctly assigning each signal is essential for elucidating new structurally related compounds. Furthermore, the ambiguity of several compounds, the structure of which differs in the literature and the Sci-Finder database, has been eliminated. Misassigned structures were found by chemical shift searches in NAPROC-13, and the results provide two or more different compounds with the same 13C NMR data. The process to determine the correct, most likely structural proposal in agreement with the experimental 13C NMR data was carried out by DFT calculations.

Modification of extended chemical percolation devolatilization model for application to low-rank coals

For understanding coal gasification reactions, primary pyrolysis reaction is important as the first stage of the gasification reactions. Recently, the authors developed a primary pyrolysis model to predict tar formation behavior by extending the chemical percolation devolatilization (CPD) model which is often used to predict pyrolysis behavior. The extended CPD (Ex-CPD) model predicts gas and tar components as respective chemical species. Consequently, the secondary tar decomposition behavior can be calculated by elementary step-like reaction models. However, some of the coal structure parameters used in the model contradict the 13C NMR data. That is, the molecular weight of the aromatic ring clusters calculated by the original Ex-CPD decreases with the aromatic index obtained by 13C NMR. In this study, this problem was resolved by modifying the calculation procedure to determine the coal structure parameters. The recalculated aromaticity index agreed with that calculated from the 13C NMR data. The modified Ex-CPD model was validated through comparison with coal gasification experiments using a pressurized drop tube furnace. The calculation results successfully described the trend of light gases, soot, and char yield in the experiments.