13C NMR Research Articles

Ionic liquid-catalyzed, microwave-assisted green synthesis of novel Coumarin-Schiff bases: Characterization, molecular docking, biological and DFT studies

A microwave assisted green protocol for the synthesis of coumarin-linked novel Schiff base compounds (CSB-I and CSB-II) were demonstrated by employing [TMG][OAc] ionic liquid (IL) as dual catalyst and solvent. The resulted compounds were characterized by several spectroscopic techniques such as FT-IR, 1H NMR, 13C NMR and GC–MS. The efficiency of the ionic liquid employed is evaluated by recycle and reuse of the same for number of cycles (upto 5). The HOMO and LUMO energy levels for each Schiff base were meticulously calculated using Density Functional Theory (DFT). The electrophilic and nucleophilic sites were identified by Molecular Electrostatic Potential (MESP) 3D plots, based on DFT computational analysis. Further, Global Chemical Reactivity Descriptor (GCRD) parameters including chemical potential (μ), chemical hardness (ղ), softness (S), electrophilicity index (ω) and electronegativity (χ) were also evaluated with precision. The molecular docking studies were also performed to evaluate the behavior of binding interaction of new Schiff bases (CSB-I and CSB-II) with mevalonate-5-diphosphatedecarboxylase (PDB ID: 1FI4) and human lanosterol 14-alpha-demethylase, CYP51 (PDB ID: 3LD6) proteins. The outcome of this study reveals that CSB-I exhibited strong binding to both the proteins as compared to CSB-II. The antibacterial study revealed that CSB-I was highly effective against both Gram-positive and Gram-negative bacteria, while CSB-II showed moderate activity. In antifungal studies, both the compounds showed excellent activity profiles against yeast fungi, while both had only moderate effects on filamentous fungi.

Evaluation of Fifteen 5,6-Dihydrotetrazolo[1,5-c]quinazolines Against Nakaseomyces glabrata: Integrating In Vitro Studies, Molecular Docking, QSAR, and In Silico Toxicity Assessments

Nakaseomyces glabrata (Candida glabrata), the second most prevalent Candida pathogen globally, has emerged as a major clinical threat due to its ability to develop high-level azole resistance. In this study, two new 5,6-dihydrotetrazolo[1,5-c]quinazoline derivatives (c11 and c12) were synthesized and characterized using IR, LC-MS, 1H, and 13C NMR spectra. Along with 13 previously reported analogues, these compounds underwent in vitro antifungal testing against clinical N. glabrata isolates using a serial dilution method (0.125–64 mg/L). Remarkably, compounds c5 and c1 exhibited potent antifungal activity, with minimum inhibitory concentrations of 0.37 μM and 0.47 μM, respectively—about a 20-fold improvement in μM concentration over standard drugs like amphotericin B, caspofungin, and micafungin. A detailed structure–activity relationship analysis revealed crucial molecular features enhancing antifungal potency. Extensive molecular docking studies across 18 protein targets explored potential binding pockets and affinities of the lead compounds. A robust 3D-QSAR model, incorporating molecular descriptors Mor26m and Mor29e, displayed good predictive ability for antifungal activity. In silico predictions indicated an absence of herbicidal effect, negligible environmental toxicity (to honeybees, avian species, and aquatic organisms), and mild human toxicity concerns for these compounds. This comprehensive approach aims to develop novel and effective antifungal compounds against the clinically relevant pathogen N. glabrata.

Vibrational spectroscopic characterization, quantum chemical, molecular docking and molecular dynamics investigations of cyclo(L-phenylalanyl-L-proline), an anticancer agent

The molecular structure and spectral properties of cyclo(L-Phenylalanyl-L-Proline) dipeptide, which has several biological activities, were investigated. Firstly, conformational preference of the cyclo(L-Phenylalanyl-L-Proline) was searched and obtained lowest energy conformer of the cyclic dipeptide was then optimized using Density Functional Theory with wb97xd/6-311++G(d,p) level of theory. A detailed vibrational spectral analysis has been carried out and assignments of the fundamental modes have been proposed. The experimental vibrational wavenumbers of the investigated compound display good agreement with the computed values. The Frontier Molecular Orbitals, Molecular Electrostatic Potential and electronic transitions of the investigated compound were discussed. In addition, the 1H and 13C NMR chemical shifts of the cyclic dipeptide were calculated and the results were compared with the experimental values. Also, to evaluate the anticancer potential, molecular docking studies of cyclo(L-Phenylalanyl-L-Proline) within the ATP-binding sites of both wild type (EGFRWT; ID: 4HJO) and mutant (EGFRT790M; ID: 3W2O) Epidermal Growth Factor Receptor were performed. The results indicated that cyclo(Phe-Pro) has high binding affinities toward both EGFRWT (−6.6 kcal/mol) and EGFRT790M (−7.7 kcal/mol) receptors, thus, has good anticancer activity and also has potential to overcome drug resistance in therapy. Molecular dynamics simulations on cyclo(L-Phenylalanyl-L-Proline)-wild type complex were conducted through a 50-nanosecond timed to investigate the ligand-receptor interactions in more detail, and to determine the binding free energy accurately. The binding free energy of the cyclo(L-Phenylalanyl-L-Proline)-wild type complex was calculated to be −27.18 kcal/mol.

Thiourea based fluorescent chemosensor for selective detection of mercury ions in real samples and live cells imaging

A novel fluorescent sensor L having a thiourea moiety was devised and characterized by using FTIR, 1H NMR, 13C NMR and ESI-MS spectrometry. The receptor L effectively detects Hg2+ using a binding site-signalling approach in which the thiourea moiety serves as the binding unit and the phenol group serves as the signalling unit. Noticeable changes in the UV–Vis and emission spectra of L have been observed when reacts with Hg2+, as well as a visible color change in DMSO/H2O (10:90, v/v) solution. The X-ray photoelectron spectroscopy (XPS) investigation was performed to analyze the involvement of functional groups in the mercury complexation. The SEM analysis was also utilized to investigate the morphology of L. The limit of detection and association constant were calculated to be 0.60 µM and 1.63 × 104 M−1, respectively. L has been effectively utilized for the recognition of Hg2+ in soil samples, serum sample and live cells.

Synthesis, characterization, biological activity, and modelling protein docking of divalent, trivalent, and tetravalent metal ion complexes of new azo dye ligand (N,N,O) derived from benzimidazole

The ligand 2-[2′-(benzimidazole)azo]-4,6-dimethyl benzoic acid (BADMB) was employed to create coordination complexes with Pd(II), Co(III), and Pt(IV) ions. A variety of analytical methods were utilized to verify the structures of the synthesized chelates, including microanalysis, 1H NMR, 13C NMR, UV–Vis spectroscopy, FT-IR, mass spectrometry, magnetic susceptibility, molar conductivity, X-ray diffraction (XRD), and thermal analysis. The stoichiometry of the metal complexes was 1:1 [M:L] in the case of both Pd(II) and Pt(IV) complexes while that of the Co(III) complex was 1:2 [M:L]. The results of molar conductivity measurements confirmed that all of the complexes are electrolytes and that they fall within the range 15.74–40.11 Ω−1 cm2 mol−1. The findings indicated that the Co(III) and Pt(IV) complexes adopt an octahedral geometry, with the formulas [Co(BADMB)2]Cl·H2O and [Pt(BADMB)Cl3]·H2O, respectively. In contrast, the Pd(II) complex, represented by the general formula [Pd(BADMB)Cl]·H2O, has a square planar geometry. BADMB acts as a trident (N,N,O) ligand through two nitrogen atoms from the benzimidazole ring and an azo group and one oxygen atom of the carboxyl group. The antimicrobial activity of these compounds was evaluated against a variety of microorganisms, including Streptococcus, Staphylococcus aureus, Penicillium spp., and Aspergillus, as well as multidrug resistance. In addition, all compounds were active against Penicillium spp. fungi compared to the other microorganisms examined. Moreover, the cytotoxic effects of the BADMB, Pd(II), and Pt(IV) complexes were evaluated in a human hepatocellular carcinoma cell line (HepG2) and a normal cell line (WRL68). A molecular docking study was performed using MOE 2015 software and the PDBsum online server. The compounds showed a binding free energy greater than 5 kcal/mol and an RMSD value was present in the range of 1.41 to 2.01 Å, indicating their potential as ligands for further molecular studies with selected targets.

Physiochemical properties optimization of synthetic bio-destructible 2,6-bisarylidene-4-(t.-butyl)cyclohexanones to select a potential anti-cancer drug contender

A series of 2,6-bisarylidene-4-(t.-butyl)cyclohexanones 5(a-h) have been synthesised using Claisen–Schmit condensation and the resultant analogy were characterized by FT-IR, 1H NMR, and 13C NMR spectral techniques. The crystal structure of the three synthesised organic compounds 5a, 5b and 5c have been determined using X-ray diffraction (XRD) analysis. A quantitative investigation of intermolecular interactions was conducted using two-dimensional fingerprint plots and three-dimensional Hirshfeld surface (3D-HS) analysis and the estimated interaction energies and energy frames were discussed. Utilizing the density functional theory (DFT) the quantum phenomena of synthesized compounds were calculated and investigation on prohibited energy gap by computing frontier molecular orbitals, namely HOMO-LUMO, was also recorded. The physiochemical and pharmacokinetic features of the synthesised compounds 5(a-h) were computed and analyzed using the SwissADME online application. Synthesized compounds were screened by docking investigations utilizing the PDB codes 3ert, 1smd, 1smd, 1htb, 1drf, 3nby, 4tzk and 6fe2. the results confirmed that all the drug candidates selected found to enhance the binding affinities against each of those mentioned proteins. Furthermore, the anti-breast cancer potential of the drug candidates has been evaluated based on the docking results. Comparable results have been obtained for the produced compounds against the regular drugs, the former demonstrated a fair efficacy against breast cancer.

Polymerization potential of a bacterial CotA-laccase for β-naphthol: enzyme structure and comprehensive polymer characterization.

Laccases are blue-multicopper containing enzymes that are known to play a role in the bioconversion of recalcitrant compounds. Their role in free radical polymerization of aromatic compounds for their valorization remains underexplored. In this study, we used a pBAD plasmid containing a previously characterized CotA laccase gene (abbreviated as Bli-Lacc) from Bacillus licheniformis strain ATCC 9945a to express this enzyme and explore its biotransformation/polymerization potential on β-naphthol. The protein was expressed from TOP10 cells of Escherichia coli after successful transformation of the plasmid. Immobilized metal affinity chromatography (IMAC) was used to generate pure protein. The biocatalytic polymerization reaction was optimized based on temperature, pH and starting enzyme concentration. 1H and 13C solution nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and solid-state NMR (ssNMR) were used to characterize the formed polymer. A one-gram conversion reaction was done to explore applicability of the reaction in a pilot-scale. The polymerization reaction generated a brown precipitate, and its chemical structure was confirmed using 1H and 13C NMR and FTIR. SsNMR revealed the presence of two different orientational hydroxyl functional groups in the polymer in addition to the presence of a very small amount of ether linkages (< 2%). This analysis elucidated that polymerization occurred mainly on the carbons of the aromatic rings, rather than on the carbons attached to the hydroxyl groups, resulting in a condensed ring or polynuclear aromatic structure. The reaction was optimized, and the highest yield was attained under conditions of 37°C, pH 10 and a starting enzyme concentration of 440 nM in 50 mM phosphate buffer. A one-gram conversion yielded 216 mg of polymer as dry mass. The crystal structure of the enzyme was solved at 2.7 Å resolution using X-ray crystallography and presented with a hexagonal space group. The final structure was deposited in the Protein Databank (PDB) with an ID-9BD5. This article provides a green/enzymatic pathway for the remediation of phenolics and their valorization into potential useful polymeric materials. The comprehensive analysis of the formed polymer provides insight into its structure and functional moieties present. Based on the yield of the one-gram conversion, this synthetic method proves useful for a pilot-scale production level and opens opportunities to invest in using this polymer for industrial/environmental applications.

Naphthalen-2-yl-N′-(2-hydroxybenzoyl)benzohydrazonate as dual metal ion chemosensor for the detection of Fe3+ and Na+ ions

New probe naphthalen-2-yl-N′-(2-hydroxybenzoyl)benzohydrazonate (NHBH) chemosensor has been prepared and characterized by IR, 1H NMR, 13C NMR and Mass Spectroscopic techniques. The probe (NHBH) was subjected to study its cation sensing ability with twelve different metal chloride salt (Al3+, Ca2+, Co2+, Cr3+, Fe3+, Cu2+, Mn2+, Ni2+, Zn2+, Hg2+, K+ and Na+) in 1:4 methanol water medium by using absorption and emission titration experiments. The results showed that the probe detected Fe3+ and Na ​+ ​ions by showing absorption enhancement and fluorescence emission quenching. Further, NHBH exhibited good selectivity for Fe3+ and Na ​+ ​ions in the presence of mostother metal ions. Job's plot analysis authenticated the 1:1 binding nature of NHBH with Fe3+ and Na ​+ ​ions. Further, DFT studies validated the formation of probe (NHBH), fluorophore-quencher (Fe-NHBH) complex formation.

Synthesis of 5H-thiazolo[2′,3′:2,3]imidazo[4,5-b]indole Fused Hybrid Structures via Copper-Catalyzed Sequential C-N Coupling Reactions

In this study, we developed a simple and efficient synthetic procedure to obtain novel imidazothiazole-indole fused hybrid compounds through sequential C-N coupling reactions using copper catalysts. The key reaction was performed between 5-bromo-6-(2-bromophenyl)imidazo[2,1-b]thiazole derivatives and various amines, allowing for a significant expansion of the structural scope of the products compared to the use of nitrile derivatives. Optimal reaction conditions were identified, employing the CuI/ethyl 2-oxocyclohexane-1-carboxylate catalyst system, providing high overall yields (76-85%). Using this method, we successfully synthesized four new compounds (7c-f). The structures of all compounds were confirmed by 1H-NMR and 13C-NMR spectroscopy. This work presents a valuable contribution to the field of heterocyclic chemistry, offering a practical and versatile approach for the synthesis of diverse imidazothiazole-indole hybrids with potential applications in medicinal chemistry and materials science.

Gelation during Ring-Opening Reactions of Cellulosics with Cyclic Anhydrides: Phenomena and Mechanisms.

Cellulose esters are used in Food and Drug Administration-approved oral formulations, including in amorphous solid dispersions (ASDs). Some bear substituents with terminal carboxyl moieties (e.g., hydroxypropyl methyl cellulose acetate succinate (HPMCAS)); these ω-carboxy ester substituents enhance interactions with drug molecules in solid and solution phases and enable pH-responsive drug release. However, the synthesis of carboxyl-pendent cellulose esters is challenging, partly due to competing reactions between introduced carboxyl groups and residual hydroxyls on different chains, forming either physically or covalently cross-linked systems. As we explored ring-opening reactions of cyclic anhydrides with cellulose and its esters to prepare polymers designed for high ASD performance, we became concerned upon encountering gelation. Herein, we probe the complexity of such ring-opening reactions in detail, for the first time, utilizing rheometry and solid-state 13C NMR spectroscopy. Gelation in these ring-opening reactions was caused predominantly by physical interactions, progressing in some cases to covalent cross-links over time.

Highly Potent Fluorenone Azine-based ESIPT Active Fluorophores for Cellular Viscosity Detection and Bioimaging Applications.

Herein, synthesizes of fluorenone azine-based Schiff fluorescence probes: (E)-2-(((9H-fluoren-9-ylidene)hydrazineylidene)methyl)-5-(diethylamino)phenol (3a), (E)-9-(((9H-fluoren-9-ylidene)hydrazineylidene) methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol (3b), and (E)-1-(((9H-fluoren-9-ylidene)hydrazineylidene)methyl) naphthalen-2-ol (3c). The probes were structurally characterized using Fourier-transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry(HRMS) analysis. The probes exhibit hydrogen bonding between phenolic -OH and imine nitrogen, enabling excited state intramolecular proton transfer (ESIPT) and free rotation in the azine (> C = N-N = C <) functional, facilitating twisted intramolecular charge transfer (TICT), and a positive solvatochromism in solvent-dependent emission studies. Further, density functional theory (DFT) based calculations accounted for the observed photophysical TICT and ESIPT processes, revealing a non-covalent interaction between phenolic -OH and imine nitrogen. Furthermore, the fluorescence intensity (log I) showed good linearity (R2 = 0.999) with the viscosity (log η) with Förster-Hoffmann coefficient (X) values of 2.238, 1.405 and 3.121 for 3a, 3b and 3c, respectively. The study established the probes toxicity and fluorescence imaging in the Caenorhabditis elegans model. Probe 3a, the first azine-based probe for micro viscosity detection, demonstrated exceptional efficacy in detecting intercellular viscosity and facilitating bioimaging applications.

Preparation of cellulose-based optical brightening agent by a two-step one-pot reaction and its application in fiber treatment

AbstractA simple and efficient two-step one-pot procedure for the manufacturing of a cellulose-based polymeric optical brightening agent is demonstrated. The method employs a consecutive in situ activation of two carboxylic acids in a cellulose solution prepared in N,N-dimethylacetamide and LiCl. As an activating agent, 4-toluenesulfonyl chloride was employed. The optical brightening properties were introduced by a 4-hydroxythiazole moiety. These compounds show strong fluorescence over a large range of the visible electromagnetic spectrum. The properties can be largely tuned by reactions at the 2- and 5-position of the thiazole ring. The water solubility of the cellulose derivative is introduced in the second step, by attaching betaine to the cellulose backbone. This cationic moiety allows not only a fast dissolution of the cellulose mixed ester in water, but also an efficient adsorption onto cellulose fibers via electrostatic interactions. After adsorption onto the fibers, the resulting material appears bright white in daylight and shows a strong blue fluorescence when probed under ultraviolet light. The coating process is fast and almost quantitative as absorption and fluorescence measurements reveal, showing no leaching effect. The cellulose mixed ester synthesized is characterized by means of 1D and 2D 1H- and 13C nuclear magnetic resonance, infrared-, UV–Vis-, and fluorescence spectroscopy. In addition, elemental analysis and size-exclusion chromatography were performed. The polymeric optical brightening agents presented consists of environmentally benign compounds only and can be considered as a green alternative for traditional low molecular optical brightening agents employed today.

New alkoxyphenyl azomethine phenyl toluate liquid crystals

ABSTRACT A series of alkoxyphenyl azomethine phenyl toluates was synthesised and investigated for thermal and liquid crystalline behaviour. All the synthesised compounds were characterised using FT-IR, 1H NMR and 13C NMR spectroscopy. The materials demonstrated high thermal stability in thermogravimetric analysis (TGA), undergoing decomposition above 280°C. Mesomorphic properties were investigated using a combination of differential scanning calorimetry (DSC) and polarising optical microscopy (POM). All final compounds exhibited liquid-crystalline properties, displaying textures characteristic of calamitic liquid crystals. There was a tendency for lower homologs to display enantiotropic behaviour (N), while higher homologs exhibited dimesomorphic behaviour (N and SmC). The mesophases were confirmed through X-ray diffraction studies. A comparison with similar compounds revealed that interchanging the positions of methyl and alkoxy end groups influenced the nematic phase stabilities in lower homologues and led to a transition from SmA to SmC in higher homologues.

Study on the enhancement of oxidation activity of heated coal in closed fire area and mechanism of reignition by opening seal

Residual heat following the closure of a coal mine fire area induces alterations in the physical and chemical structure of coal, which not only interfere with the opening time but also engenders potential catastrophic incidents upon the reopening of the fire area. Therefore, the structural changes in coal before and after pyrolysis were first analyzed by SEM, BET, XPS, 13C NMR and ESR. Second, the crossing-point temperature and constant-temperature differential heat methods were employed to investigate the process and characteristics of alkyl radical oxidation heat production. Quantum chemistry was integrated to analyze the mechanism of coal oxidation activity enhancement when the fire area was unsealed. The experimental results revealed that the residual heat could induce physicochemical structural changes in coal at varying distances. Upon exposure to oxygen, cracks facilitate oxygen migration and water evaporation mitigates heat consumption. The low-energy barrier of the alkyl radical oxidation reactions intensifies the oxidation activity of pyrolyzed coal, which can react with oxygen at room temperature to release heat. Under heat storage conditions, the active groups in coal are stimulated to further react. As a corollary, the substantial release of heat occurs, heightening the risk of coal re-ignition upon reopening of the fire area. The research results are helpful in performing accurate targeted treatment for different temperature gradients in underground fire areas to prevent the reignition of heated coal in closed fire areas.

Structure of the K58 capsular polysaccharide produced by Acinetobacter baumannii isolate MRSN 31468 includes Pse5Ac7Ac that is 4-O-acetylated by a phage-encoded acetyltransferase

Capsular polysaccharide (CPS), a heteropolymeric carbohydrate structure present on the cell surface of most isolates of the bacterial pathogen Acinetobacter baumannii, is a major virulence determinant. Here, the CPS produced by A. baumannii MRSN 31468, which carries the KL58 CPS biosynthesis locus, was studied by sugar analysis, one- and two-dimensional 1H and 13C NMR spectroscopy. The structure was found to consist of a repeating tetrasaccharide K-unit that includes glucose (d-Glcp), galactose (d-Galp), N-acetyl-galactosamine (d-GalpNAc), and 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (5,7-di-N-acetylpseudaminic acid; Pse5Ac7Ac). The CPS has a branched repeating unit with the disaccharide →3)-β-d-Glc-(1→3)-β-d-GalNAc-(1→ as the mainchain and O-6 of the Glc unit substituted with the disaccharide β-Pse5Ac7Ac-(2→6)-α-d-Gal, and Pse5Ac7Ac is partially acetylated at O-4. The presence of Pse5Ac7Ac in the K58 structure is consistent with the presence of psaA-F genes in KL58, which are responsible for Pse5Ac7Ac synthesis. 4-O-acetylation of Pse5Ac7Ac was traced to an acetyltransferase, Atr44, which was found to be closely related to Atr29 that similarly decorates Pse5Ac7Ac with 4OAc in the K46-type CPS. Atr44 like Atr29 is encoded by a gene found in a prophage. The K58 CPS produced by MRSN 31468 did not include the 8-epimer of Pse5Ac7Ac (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) found in the closely related CPS from BAL062 that also carries KL58. Hence, the gene(s) for conversion of Pse5Ac7Ac to 8ePse5Ac7Ac must lie elsewhere.

Engineered Mg-modified biochar-based sorbent for arsenic separation and pre-concentration

The utilization of biochar as a relatively efficient sorbent or stationary phase for the separation and preconcentration of a wide range of analytes represents an innovative approach in current sample pretreatment methods. Appropriate pre- and post-pyrolysis modification of the input precursor and pyrolysis product, respectively, allows targeted design of the physicochemical properties and sorption characteristics of the resulting sorbent. The present work deals with the preparation of pyrolysis materials based on unmodified cattail leaf biomass (BC) and its Mg-modified analogue (MgBC) by a slow pyrolysis process at 500 °C and a residence time of 1 h in a pyrolysis reactor. Physicochemical characterization of BC and MgBC carried out by pH, total C, N, surface size analysis (SSA), 13C NMR, SEM-EDX and XRD confirmed significant morphological and mineralogical differences between the prepared sorbents. By performing sorption experiments using a model anionic analyte (As) and application of Langmuir isotherm, we found that the predicted maximum sorption capacity of MgBC for As is 13.5-fold higher than that of BC. The sorption process of As by both sorbents is best described by the Sips adsorption isotherm (R2 ≥ 0.995) and a pseudo-nth order kinetic model (R2 ≥ 0.997). The optimum pH for As sorption by BC and MgBC sorbents is in the interval 5–6. The presence of competitive phosphate anions (equimolar concentration of 1:1) in the solution significantly reduces the sorption capacity of MgBC for As by 40% for BC by 70%. The presence of Cl- ions showed no significant effect on the sorption capacity of Bc and MgBC for As. Both sorbents were best recovered using 0.1 mol/L NaOH solution when the desorption efficiency for both sorbents was more than 95%. The MgBC sorbent showed 35% retention of As from the real sample in the model SPE column at a flow rate of 0.12 mL/s. Based on the obtained knowledge, it is evident that biochar-based sorbent prepared from Mg-modified precursor represents an effective sorbent for anionic forms of analytes and opens the possibility of its use also in preconcentration and separation techniques.

Design, synthesis and spectral characterization of cyclotriphosphazenes including heterocyclic rings

In this study, described the synthesis on a cyclotriphosphazene containing the spirocyclic 2,2′-dioxybiphenyl group and 2-mercapto-1-methylimidazole (methimazole) or 2-mercaptothiazoline (MTZ) moieties. These spiro(in difunctional ligands, both ends are bound to the same phosphorus) cyclotriphosphazene derivatives (6, 7a) were synthesized in two steps. In first step; mono substituted phosphazene compounds 2,4,4,6,6-pentachloro-2-(2-mercapto-1-methylimidazolyl) cyclo2λ5, 4λ5, 6λ5, triphosphazatriene; N4P3Cl5C3S2H5 (4), and 2,4,4,6,6-pentachloro-2-(2-mercapto-tiyazolinyl) cyclo2λ5, 4λ5, 6λ5, triphosphazatriene; N4P3Cl5C4S2H4 (5)] were prepared from the reaction of hexachlorocyclotriphosphazatriene (trimer, N3P3Cl6, 1), with methimazole (2) or MTZ (3) in tetrahydrofurane (THF) in the presence of metallic sodium under an argon atmosphere.In second step; monospiro2-mercaptothiazolinyl (7a) and dispiro2-mercapto-1-methylimidazolyl sübstituted (6) phosphazene derivatives were obtained from the reactions of 4 and 5 with 2,2′-dihydroxybiphenyl (8) in acetone in the presence of potassium carbonate (K2CO3). Structural characterizations of all obtained compounds were made using by elemental analysis, FT-IR, 1H, 13C and 31P NMR spectroscopies. Compounds 5–7a are reported for the first time in this study.

Design and Synthesis of 2-(5-ethyl-pyridine-2-yl) ethanol Analogs as Potential Microbial Agents

A novel series of chalcones and pyrimidines is described. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, 1H NMR and 13C NMR spectral data. All the products were screened against different strains of bacteria and fungi. Most of these compounds showed better inhibitory activity in comparison to the standard drugs.

Chemical constituents from the culture of Biscogniauxia capnodes SWUF15-40 fungus and the inhibitory activity against cancer cell proliferation and nitric oxide production

The chemical diversity from Biscogniauxia capnodes SWUF15-40 fungus, cultivated in yeast-malt extract medium was studied. The choice of medium was inspired by the OSMACs strategy, which had previously been cultivated in PDB medium. This resulted in an array of bioactive compounds being discovered. The IR, NMR, MS, and XRD data, together with the calculated 13C NMR chemical shifts and ECD spectra data were thoroughly analysed, which led to the determination of two new isopimarane (1 and 2), and three guaiane (3−5) derivatives, together with four known compounds (6−9). Cyclic pentapeptide (9) showed inhibitory activity against cancer cells (HeLa, HT-29, PC-3, and A549) proliferation and nitric oxide (NO) production in LPS-stimulated RAW264.7 cells with IC50 values in the ranges of 11.38 − 17.87 µM, and 58.88 µg/mL, respectively. The results demonstrated that manipulating growth conditions can increase the possibility of discovering many more bioactive compounds in fungi.

5,5’-Selenobis(1-benzyl-2-oxo-1,2-dihydropyridine-4-carbaldehyde)

Selenium compounds have garnered significant attention in the field of medicinal chemistry due to their unique biochemical properties and potential therapeutic applications for different pathologies. In this study, we report the synthesis of a new selenylated bis-pyridone compound using SeO2 as the source of selenium. Detailed 1H and 13C NMR characterizations and mass spectral analysis are given.