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To develop a green drilling fluid additive, the modification and application of persimmon peel in a water-based drilling fluid was studied in this work. A natural product derivative, aluminium chloride–persimmon peel (ACPP), was prepared from aluminium chloride and persimmon peel and was assessed as a shale inhibitor. The clay-swelling ratio in 0.30% ACPP-3 solution was reduced to 28.10% from 69.50%. The rolling recovery tests and rheological evaluation of drilling fluids concluded that ACPP-3 has a high inhibition property to montmorillonite-hydrated expansion. ACPP-3 can adjust the particle size of montmorillonite to a large degree. ACPP-3 effectively reduces the apparent viscosity of carboxymethyl cellulose drilling fluids and the volume of filtration; furthermore, ACPP-3 can reduce the viscosity and the volume of filtration under high temperature, which means it can be used as an additive for deep drilling. The inhibition mechanism of ACPP-3 was investigated by thermogravimetric analysis and scanning electron microscopy. The results of this scientific research will be beneficial to the eco-friendly drilling fluid materials.

Conformational regulation among two or more distant sites is not only one of the main pathways to accomplish multiple tasks in complex biological systems but also represents a powerful strategy to obtain stimuli-responsive supramolecular nanoconstructs with tailored physicochemical performance. We herein report the fabrication of a photochromic supramolecular assembly, which can be synergistically activated by the conformational regulation with bis(4,8-disulfonato-1,5-naphtho)-32-crown-8 and then reversibly switched by the through-space communication between restricted stilbazolium salt and photochromic dithienylethene. This work demonstrates that the synergistic conformational modulation via intra- and intermolecular interactions can be developed as a generalizable approach to construct more advanced biomimetic nanomaterials.

A propylimidazole functionalized coumarin derivative (IPC) was fabricated for the first time and applied as a dual responsive fluorescent chemoprobe for sensitive and selective recognitions of picric acid (PA) and Fe3+. Strong fluorescence quenching phenomena of the IPC were observed in H2O/ACN (5/95, v/v) medium (λem=408 nm) upon the additions of Fe3+or PA. The fabricated dual responsive IPC offered good selectivity and sensitivity with the low limit of detection values (0.92 µM for PA and 0.22 µM for Fe3+) lower than the acceptable amounts of Fe3+ and PA by the international official authorities. The interaction phenomena of IPC with PA and Fe3+ based on the findings of a range of experiments were considered and DFT computations were done to verify their recognition mechanisms. The sensing phenomena of IPC towards PA (1:1) and Fe3+ (3:1) were confirmed by the MALDI TOF–MS, FT–IR, 1H–NMR titration and Job's methods. Furthermore, the compound IPC was effectively applied as a fluorescent sensor for Fe3+ and PA detection in real natural spring water samples.

bicyclic [3.2.1] octane neolignans have garnered increasing interest, because of their unique structural features and biological activities. This study describes the isolation and identification of a new bicyclic octane neolignan 1 obtained through fractionation of the crude extract of the stem of Aniba firmula (Lauraceae family). The structure of bicyclic octane neolignan 1 was determined through NMR analysis and mass spectrometry data.

Aims: The present investigation is targeted towards the synthesis of a novel analogue of a natural peptide of marine origin. Background: Marine sponges are enriched with bioactive secondary metabolites, especially circu-lar peptides. Heterocycles are established organic compounds with potential biological value. Tak-ing into consideration the bio-properties of heterocycles and marine sponge-derived natural pep-tides, an effort was made for the synthesis of a heterocyclic analogue of a natural cyclopeptide. Objective : A heterocyclic analogue of a sponge-derived proline-containing cyclic peptide, rolloam-ide A, was synthesized by interaction of Boc-protected L-histidinyl-L-prolyl-L-valine and L-prolyl-L-leucyl-L-prolyl-L-isoleucine methyl ester and compared with synthetic rolloamide A with bioac-tivity against bacteria, fungi, and earthworms. Methods: The synthesis of cycloheptapeptide was accomplished employing the liquid phase method. The larger peptide segment was prepared by interaction of Boc-protected L-prolyl-L-leu-cine with L-prolyl-L-isoleucine methyl ester. Similarly, the tripeptide unit was synthesized from Boc-protected L-histidinyl-L-proline with L-valine ester. The linear heptapeptide segment (7) was cyclized by utilizing pentafluorophenyl (pfp) ester, and the structure was elucidated by elemental and spectral (IR, 1H/13C NMR, MS) analysis. The peptide was also screened for diverse bioactivities such as antibacterial, antifungal, and potential against earthworms and cytotoxicity. Results: The novel cyclooligopeptide was synthesized with 84% yield by making use of car-bodiimides. The synthesized cyclopeptide exhibited significant cytotoxicity against two cell lines. In addition, promising antifungal and antihelmintic properties were observed for newly synthesized heterocyclic peptide derivative (8) against dermatophytes and three earthworm species at 6 μg/mL and 2 mg/mL, respectively. Conclusion: Solution-phase technique employing carbodiimide chemistry was established to be promising for synthesizing the cycloheptapeptide derivative (8), and C5H5N was proved to be a better base for heptapeptide circling when compared to N-methylmorpholine and triethylamine.

Background and Objectives: SM-1 is a new synthetic small molecule compound with antitumor activity. The metabolism of SM-1 is a key parameter that needs to be evaluated to provide further insight into drug safety and efficacy in the early phases of drug development. Methods and Results: In this study, the biotransformation process of SM-1, including the metabolic pathways and major metabolites, was investigated based on a liquid chromatography-mass spectrometry method. Upon incubation of SM-1 with human liver microsomes, five metabolites were identified, namely dihydrodiol formation (R1), hydroxylation (R2, R3, and R5), and debenzylation (R4) of SM-1, with R1 and R4 being the major metabolites. The enzyme kinetic parameters of SM-1 were determined by a liquid chromatography-tandem mass spectrometry method. The enzyme kinetics of SM-1 obeyed the Michaelis-Menten equation. The Vmax, Km, and CLint of SM-1 in HLMs were 14.5 nmol/mg protein/h, 6.32 μM, and 2.29 mL/mg protein/h, respectively. Results: The chemical inhibition studies showed that CYP450 isoenzymes were responsible for SM-1 metabolism in HLMs, and CYP3A4 was the major CYP450 isoenzyme involved in the metabolism of SM-1; these findings were confirmed by using the human recombinant CYP3A4. Conclusion: Through the identification of the biotransformation pathways and enzyme kinetics of SM-1, the metabolic enzymes for SM-1 in HLMs are characterized.

Aim: Selective and sensitive visual detection of Cu2+in aqueous solution at PPB level using easily synthesized compound. Background: The search for a chemosensor that can detect Cu2+ is very long owing to the fact that an optimum level of Cu2+ is required for human health and the recommended amount of Cu2+ in drinking water is set to be 1-2 mgL-1 . Thus, it is very important to detect Cu2+ even at a very low concentration to assess the associated health risks. Objective: We are still seeking for the easiest, cheapest, fastest and greenest sensor that can selectively, sensitively and accurately detect Cu2+ with lowest detection limit. Our objective of this work is to find one such Cu2+ sensor. Methods: We have synthesized a quinoline derivative following very easy synthetic procedures and characterize the compound by standard methods. For sensing study, we used steady state absorption and emission spectroscopy. Results: Our sensor can detect Cu2+ selectively and sensitively in aqueous solution instantaneously even in the presence of excess amount of other salts. The pale-yellow color of the sensor turns red on the addition of Cu2+ . There is no interference from other cations and anions. A 2:1 binding mechanism of the ligand with Cu2+ is proposed using Jobs plot with binding constant in the order of 109 M-2 . We calculated the LOD to be 18 ppb, which is quite low than what is permissible in drinking water. Conclusion: We developed a new quinoline based chemo-sensor following straightforward synthetic procedure from very cheap starting materials that can detect Cu2+ visually and instantaneously in aqueous solution with ppb level sensitivity and zero interference from other ions.

For side-chain liquid-crystalline polymers (SCLCPs) bearing calamitic mesogens, nematic and typical smectic (Sm) phases are expected. Here, using a precise polyethylene derivative with the biphenyl...

Methods: PLSR method is applied for 2D-QSAR determination of the (Z)-5-ethylidene-3-(4- methoxy-6-methyl-1,3,5-triazin-2-yl)-2-phenyl-3,5-dihydro-4H-imidazol-4-one (B1-B10). The designed compounds were synthesized and spectrally evicted by IR, 1H NMR, 13C NMR, and mass spectra data as well as biologically screened against the different antitubercular and antimicrobial species.

The preparation of amorphous pure organic room-temperature phosphorescence materials with high efficiency is still a challenging task. Herein, we introduce a CB[6] derivative-based supramolecular self-assembling strategy. A water soluble and ellipsoidal deformed CB[6] derivative is used to self-assemble with 4-(4-bromophenyl)-1-methylpyridin-1-ium chloride, bromide and hexafluorophosphate in water. After freeze-drying, the obtained amorphous complexes exhibit brilliant green phosphorescence emission under ambient conditions, with phosphorescence efficiency up to 59, 60 and 72%, respectively. This is the first report of amorphous non-polymeric pure organic room-temperature phosphorescence with such a high efficiency. In view of the dynamic self-assembling property, the complexes are responsive to water, which could enable information encryption.

A gamma-pyrone derivative, comenic acid, activates the opioid-like receptor-mediated signaling pathway that modulates the NaV1.8 channels in the primary sensory neuron membrane. These channels are responsible for the generation of the nociceptive signal; therefore, gamma-pyrones have great therapeutic potential as analgesics, and this effect deserves a deeper understanding. The novelty of our approach to the design of a medicinal substance is based on a combination of the data obtained from living neurons using very sensitive physiological methods and the results of quantum chemical calculations. This approach allows the correlation of the molecular structure of gamma-pyrones with their ability to evoke a physiological response of the neuron. Comenic acid can bind to two calcium cations. One of them is chelated by the carbonyl and hydroxyl functional groups, while the other forms a salt bond with the carboxylate anion. Calcium-bound gamma-pyrones have fundamentally different electrostatic properties from free gamma-pyrone molecules. These two calcium ions are key elements involved in ligand-receptor binding. It is very likely that ion-ionic interactions between these cations and anionic functional groups of the opioid-like receptor activate the latter. The calculated intercationic distance of 9.5 Å is a structural criterion for effective ligand-receptor binding of calcium-bound gamma-pyrones.

Solid-state fluorescent switches with reversible luminescence characteristics have attracted considerable attention because of their broad applications in advanced photonics, such as anticounterfei...

In this article, we establish certain sufficient conditions to show the existence of solutions of an initial value problem of fractional-ordinary differential equation in Banach space. Our approach is based on a combination of Mönch fixed point theorem and a suitable measure of non-compactness. Also an example is given to illustrate our approach.

This study deals with a new methodology for the production of carboxymethyl cellulose (CMC) from olive pruning residues, agricultural by-products. Cellulose was extracted by the soda?anthraquinone pulping process, and the pulp bleaching was performed using totally chlorine free (TCF) bleaching. Then, CMC microwave-assisted synthesis was performed in a homogeneous media, using DMA/LiCl as a cellulose solvent. A Box?Behnken design was applied in order to evaluate which parameters of the carboxymethylation process (viz. reaction time, reaction temperature, and amount of monochloroacetic acid) affect the degree of substitution and the yield of the synthesis reaction of this cellulose derivative. Optimized conditions to yield CMC were determined based on the desirability function approach. The prepared materials under synthesis using the optimal conditions were characterized using several analytical tools, i.e., FTIR, TGA, DSC and SEM. This cellulose derivative was successfully fabricated by a fast and efficient microwave-assisted method and thus would provide many opportunities for diverse applications.

The non-planar π-enlarged coronene-embedded coumarin achieved via pyranone-annulation and its cyanated derivative possess bright orange to red emission in both solution and solid states leaving scope for bio-imaging application. Multiple redox-states, frontier molecular orbital energy levels and strong co-facial π-stacking ability point out towards applications in organic optoelectronics.

The stress corrosion resistance of AL 2014 in high temperature acidic media usingthe inhibitors MPPA and AMPO has been evaluated using an autoclave. The liquid melt metallurgy technique using vortex method was used to fabricate AL 2014 alloy. Stress corrosion tests were conducted using weight loss method for different exposure time, normality and temperature of the acidic medium. The corrosion rates of AL 2014 alloy was lower to that of Concentration increases of the inhibitor.

Cannabidiolic acid (CBDA) is one of the most abundant phytocannabinoids found in cannabis. This compound has demonstrated interesting biological activities, including anti-cancer, anti-inflammatory, anti-emetic, and anti-convulsant. However, due to the increased emphasis on research on its derivative, cannabidiol, its potential pharmacological effects have been hidden for years. In this contribution, a systematic study of the antioxidant capacity of CBDA was conducted using advanced quantum chemistry methods. Different reaction mechanisms at all potential positions were examined for the reaction of CBDA with the hydroperoxyl radical (HOO•) and nitrogen dioxide (NO2). The influence of physiological environments and acid-base equilibrium were also taken into account. CBDA has been shown to be good HOO• and NO2 scavenger in physiological polar media with rate constants of 2.40106 and 1.30106 M-1s-1, respectively. This efficiency is mainly due to the increased activity of its dianionic form. When compared to some common antioxidants, the HOO• scavenging activity of CBDA is higher than that of Trolox and BHT (Butylated hydroxytoluene), suggesting that CBDA is a promising radical scavenger, especially in polar environments.

The nonheme iron(IV)-oxido complex trans-N3-[(L1)FeIV=O(Cl)]+, where L1 is a derivative of the tetradentate bispidine 2,4-di(pyridine-2-yl)-3,7-diazabicyclo[3.3.1]nonane-1-one, has an S = 1 electronic ground state and is the most reactive nonheme iron model system known so far, of a similar order of reactivity as nonheme iron enzymes (C-H abstraction of cyclohexane, 90 °C (propionitrile), t1/2 = 3.5 sec). The reaction with cyclohexane selectively leads to chlorocyclohexane, but “cage escape” at the [(L1)FeIII-OH(Cl)]+ / cyclohexyl radical intermediate lowers the productivity. Ligand field theory is used herein to analyze the d-d transitions of [(L1)FeIV=O(X)]n+ (X = Cl, Br, MeCN) in comparison with the thoroughly characterized ferryl complex of tetramethylcyclam (TMC=L2; [(L2)FeIV=O(MeCN)]2+). The ligand field parameters and d-d transition energies are shown to provide important information on the triplet-quintet gap and its correlation with oxidation reactivity.

Electrocatalytic palladium membrane reactors (ePMRs) use electricity and water to drive hydrogenation reactions without forming H2 gas. In these reactors, a hydrogen-permeable palladium foil physically separates electrochemical proton generation in aqueous media from chemical hydrogenation in organic media. We report herein the use of the ePMR to electrolytically hydrogenate furfural, an important biomass derivative. This system was proven to convert furfural into furfuryl alcohol and tetrahydrofurfuryl alcohol with 84% and 98% selectivities, respectively. To reach these high selectivities, we designed and built an ePMR for high-throughput testing. Using this apparatus, we tested how different solvents, catalysts, and applied currents impacted furfural hydrogenation. We found that bulky solvents with weak nucleophilicities suppressed the formation of side products. Notably, these types of solvents are not compatible with standard electrochemical hydrogenation architectures where electrolysis and hydrogenation occur in the same reaction chamber. This work highlights the utility of the ePMR for selective furfural hydrogenation without H2 gas, and presents a possible pathway for helping to decarbonize the hydrogenation industry.

Spiro[3.3]heptane-2,6-dicarboxylic acid (Fecht's acid, H2SHDC) is examined as a non-aromatic terephthalic acid isostere for the first time. The rigid spirocyclic backbone provides greater steric bulk than conventional aromatic dicarboxylates with consequences for pore chemistry and control of interpenetration, presented here in the structures of two new MOFs. Complex 1 is a three-dimensional rod packed structure consisting of Yb-carboxylate chains bridged by SHDC linkers which, although non-porous, exhibits a surprisingly high thermal stability for a spirocyclic cyclobutane derivative. Complex 2 is a co-ligand complex of SHDC with trans-1,2-bis(4-pyridyl)ethene (bpe) which contains linear solvent channels despite fourfold interpenetration. Although the framework does not retain its structure following evacuation, a clear difference is observed in the extended structure compared to the structurally related terephthalate species. This observation suggests the non-aromatic backbone of Fecht's acid and other rigid aliphatic linkers may prove an effective means to disfavour deleterious close inter-framework contacts which prevail in interpenetrated aromatic MOFs.

Simply adding ITIC derivatives, which can form a cascade energy alignment between the host donor and acceptor LUMO levels, as a small amount (5 wt%) of A2 acceptor molecules in TOSCs improved the PCE by up to 10% more than that of the BOSC system.

Reversible tricolored mechanochromism and recyclable mechanoluminescence properties (new shoots) of a reported tetraphenylethene derivative (old roots) were explored.

A new homocysteine thiolactone derivative, thiolactomide (1), was isolated along with a known compound, N-acetyl homocysteine thiolactone (2), from a culture extract of soil-derived Streptomyces sp. RK88-1441. The structures of these compounds were elucidated by detailed NMR and MS spectroscopic analyses with literature study. Biological evaluation studies revealed that both 1 and 2 exhibit neuroprotective activity against 6-hydroxydopamine (6-OHDA) mediated neurotoxicity by blocking generation of hydrogen peroxide in neuroblastoma SH-SY5Y cells.

Often associated to the colonization by Candida spp. biofilm, the catheter-related infections are a serious health problem since the absence of a specific therapy. Hence, the main objective of this work was to evaluate the activity of 8-hydroxyquinoline and quinazoline derivatives on Candida spp. biofilms. A quinazoline derivative (PH100) and an 8-hydroxyquinoline derivative (PH157) were tested against nine strains of C. albicans, C. tropicalis, and C. parapsilosis, and their biofilms in polystyrene microtiter plates and on polyurethane central venous catheter. The PH157 compound was incorporated into a film-forming system-type formulation and its capacity to inhibit biofilm formation on catheters was evaluated. The compounds were active against planktonic and sessile cells, as well as against the tested biofilms. PH157 compound performed better than the PH100 compound. The formulation containing PH157 presented results very similar to those of the compound in solution, which indicates that its activity was preserved. Both compounds showed activity against Candida spp. strains and their biofilm, with better PH157 activity. The formulation preserved the action of the PH157 compound, in addition, it facilitates its application on the catheter. The structural modifications that these compounds allow can generate compounds that are even more active, both against planktonic cells and biofilms.

Hummelen et al. for the first time reported the synthetic route and characterization of a soluble methanofullerene derivative in 1995. In the same year, such a fullerene derivative was successfully used as the acceptor of internal donor–acceptor heterojunctions in the field of organic photovoltaics (OPV). Since then, it has opened an era of fullerene derivatives towards OPV application until 2015. Beyond OPV, several new research directions for solution-processable fullerene derivatives recently appeared, including perovskite solar cells, organic thermoelectrics, molecular electronics, and organic electrochemical transistors. This review highlights the important role of fullerene derivatives in these emerging research areas and summarizes the recent progress in the development of fullerene derivatives in these new research fields. These fields require fullerene derivatives with new properties, such as strong electron-donating ability, large polarity, or excellent water permeability. Therefore, new design strategies of fullerene derivatives and device engineering considerations are desired.

The title complex, systematic name catena-poly[[[acetatochloridozinc(II)]-μ-(5R,6R,7S)-5-(furan-2-yl)-7-phenyl-4,5,6,7-tetrahydro[1,2,4]triazolo[1,5-a]pyrimidin-6-amine] monohydrate], {[Zn(C2H3O2)Cl(C15H15N5O)]·H2O} n , is the first coordination complex in which the neutral tetrahydrotriazolopyrimidine derivative acts as bridging ligand between two zinc molecules. As a result, polymeric chains of the coordination complex are found. The coordination of the zinc metal atom occurs with the lone pairs of the triazolo nitrogen atom and amino group. The positive charge of the zinc atom is compensated by the chlorine anion and deprotonated acetic acid. The coordination complex exists as a monohydrate in the crystalline phase. The water molecules bind neighbouring polymeric chains by the formation of O—H...O, O—H...Cl and N—H...O hydrogen bonds.

Three previously undescribed compounds including two ergosterols, diaporthins A and B (1 and 2), and a pyrrolidinone derivative, (±)-diaporthin C (3), together with three known compounds 4‒6, were isolated from cultures of kiwi-associated fungus Diaporthe phragmitis. The racemic 3 was further separated into pure enantiomers. Their structures with absolute configurations were elucidated by means of spectroscopic analysis, as well as single crystal X-ray diffraction analysis and electronic circular dichroism (ECD) calculations. Compounds 5 and 6 showed antibacterial activity against Pseudomonas syringae pv. actinidae with MIC values of 25 and 6.25 μg/mL, respectively.

In this study, ternary organic solar cells (OSCs) are fabricated with the PBDB-T-2F as a polymer donor and NCBDT-4Cl as a fullerene-free acceptor, double side chain fullerene derivative NC70BA as a third component material and single side chain fullerene PC71BM as reference third component materials. The NC70BA-based ternary OSCs exhibit the highest PCE of 13.82%, which is 10% higher than that of PBDB-T-2F:NCBDT-4Cl binary OSCs and slightly higher than PC71BM-based ternary OSCs (13.24%). Detailed studies suggest that the shallow LUMO levels and double side chain for NC70BA is beneficial to broaden energy bandgap and improve compatibility, which is enhancing JSC and FF value. This work suggests that double side chain fullerene derivative NC70BA as third component materials is a promising way to finely tune the detailed photovoltaic parameters and further improve the photovoltaic performance of OSCs.

In this study, initially, we provided a conceptual analysis for the rate of change interpretation of derivative from the quantitative reasoning perspective. Then, based upon the principles drawn from the quantitative reasoning perspective, the 12th-grade Turkish mathematics textbooks were analyzed, specifically focusing on the derivative topic, using the document analysis research method. The findigs indicated that mathematics textbooks are insufficient in terms of the diversity of real-life contexts. Even, the derivative as a rate of change concept is generally introduced limited with the kinematic contexts. Units of the quantities are properly used in the real-life contexts that appeared in the textbooks, however, the discussions and interpretations on the derivative concept by using the units of the quantities are not deep enough. Moreover, the covariation and relative-size ideas that are accepted to be prominent for the understanding of the rate of change are not sufficiently emphasized in all of the textbooks. The weak points in the Turkish mathematics textbooks that need to be enriched related to the concept of the derivative as a rate of change were emphasized. In the light of the findings, we also discussed the aspects that need to be developed in the textbooks provided with some samples of the real-life interpretations of the derivative as a rate of change and as relative size.

Accurate, simple, sensitive and rapid economic UV spectroscopic methods were developed for the estimation of Etizolam and Propranolol Hydrochloride in bulk and combined dosage form. The present study deals with the UV spectroscopic method development and validation for the Simultaneous Equation method and First Derivative method of Etizolam and Propranolol Hydrochloride in bulk and combined dosage form at determined wavelength of Etizolam and Propranolol Hydrochloride at 244nm and 288nm for Simultaneous Equation method and 234nm and 289nm for First Derivative Method. The linearity range for Etizolam and Propranolol Hydrochloride was 1-5µg/ml and 10-50µg/ml, and exhibit good correlation coefficient of Etizolam and Propranolol Hydrochloride was 0.9877 and 0.9977 for Simultaneous Equation method and 0.9872 and 0.9977 for First Derivative method, respectively and excellent mean recovery (98-102%). The precision was found to be within limit (%RSD

A neuroprotective compound (2) was isolated from the culture broth of the dutomycin (1) producer Streptomyces sp. RAP78. The molecular formula of 2 was established as C44H55NO16 by high-resolution FAB-MS. The structure was determined to be a new dutomycin derivative possessing an acetimidoyl group in place of an acetyl group by NMR spectroscopic analysis. 13-Deoxo-13-iminodutomycin (2) but not dutomycin (1) protected C6 rat glioma cells and N18-RE-105 rat primary retina-mouse neuroblastoma hybrid cells from glutamate-induced toxicity with EC50s of 0.12 µM and 0.72 µM, respectively.

Dengue virus (DENV) is the causative agent of dengue fever, dengue hemorrhagic disease and dengue shock syndrome (DSS), transmitted predominantly in tropical and subtropical regions by Aedes aegypti. It infects millions of people and causes thousands of deaths each year, but there is no antiviral drug against DENV. Usnic acid lately piqued the interest of researchers for extraordinary biological characteristics, including antiviral activity. Based on high larvicidal activities against Aedes aegypti, this study aims to search usnic acid derivatives as novel anti-DENV agents through a combination of ligand-based and pharmacophore-based virtual screening. One hundred and sixteen (116) usnic acid derivatives were obtained from a database of 428 in-house usnic acid derivatives through pharmacophore filtering steps. Subsequent docking simulation on DENV-3 NS-5 RdRp afforded 41 compounds with a strong binding affinity towards the enzyme. The pharmacokinetics and drug likeness prediction resulted in seven hit compounds, which eventually undergo cytochrome P450 enzyme screening to obtain the lead compound, labelled as 362. In addition, molecular dynamic (MD) simulation of lead compound 362 was performed to verify the stability of the docked complex and the binding posture acquired in docking experiments. Overall, the lead compounds have shown a high fit value of pharmacophore, strong binding affinity towards RdRp enzyme, good pharmacokinetics, and drug likeness properties. The discovery of a new usnic acid derivative as a novel anti-DENV agent targeting RdRp could lead to further drug development and optimization to treat dengue.

To determine if a C5Me5 complex of Y(II) could be isolated and to examine the synthetic accessibility of heteroleptic Y(II) complexes, the reduction of (C5Me5)2YIII(NR2) (R = SiMe3) with potassium ...

Transient amyloid intermediates are likely to be cytotoxic and play an essential role in amyloid-associated neurodegenerative diseases. Characterization of their structural and dynamic evolution is the key to elucidating the molecular mechanism of amyloid formation. Here, combining circular dichroism (CD), exciton couplet theory, and Fourier transform infrared spectroscopy with site-specific tryptophan (Trp) and its noncanonical derivative 5-cyano-tryptochan (Trp5CN), we developed a method to monitor strand-to-strand tertiary and sheet-to-sheet quaternary interactions in the aggregation cascades of an amyloidogenic fragment from protein SOD128-38 (with the sequence KVKVWGSIKGL). We found that the exciton couplet generated from the Bb band of Trp can be used as a probe for side chain interactions. Its sensitivity can be further improved by four times with the incorporation of Trp5CN. We further observed a red-shift of ∼2 cm-1 and a broadening of ∼2 cm-1 in the IR band generated from the CN stretch during the aggregation, which we attributed to the transition from a corkscrew-like structure to a cross-linked intermediate phase. We show here that the integration of optical methods with unique aromatic side chain-related probes is able to elucidate amyloid intermolecular interactions and even capture elusive transient intermediates on and off the amyloid assembling pathway.

The time-variant matrix inversion (TVMI) problem solving is the hotspot of current research because of its frequent appearance and application in scientific research and industrial production. The generalized inverse problem of singular square matrix and nonsquare matrix can be related to Penrose equations (PEs). The PEs implicitly define the generalized inverse of a known matrix, which is of fundamental theoretical significance. Therefore, the in-depth study of PEs might enlighten problem solving of TVMI in a foreseeable way. For the first time, we construct three different matrix error-monitoring functions based on PEs and propose the corresponding models for TVMI problem solving by using the substitution technique and ZNN design formula. In order to facilitate computer simulation, the obtained continuous-time models are discretized by using ZTD (Zhang time discretization) formulas. Furthermore, the feasibility and effectiveness of the novel Zhang neural network (ZNN) multiple-multiplication model for matrix inverse (ZMMMI) and the PEs-based Getz–Marsden dynamic system (PGMDS) model in solving the problem of TVMI are investigated and shown via theoretical derivation and computer simulation. Computer experiment results also illustrate that the direct derivative dynamics model for TVMI is less effective and feasible.

A carboxyl-terminated fullerene pyrrolidine derivative was synthesized by 1, 3-dipolar cycloaddition of imine ylide (FP-COOH). UV-Vis, FT-IR and MALDI-TOF respectively verified the effective synthesis of compounds. The compound (FP-COOH) was used as an intermediate, and then the hydrothermal chemical bonding method was used to load ferric oxide on the compound (FP-COOH). Its purpose was to form a magnetic targeting carrier system (FP-IONP-COOH). Then use the non-covalent method to combine FP-IONP-COOH with doxorubicin. The ultimate goal was to improve the side effects of doxorubicin. The solubility experiments showed that both FP-IONP-COOH and FP-IONP-COOH/DOX had good water solubility. The investigation of magnetism showed that FP-IONP-COOH has good magnetism. Finally, in vitro release experiments further verified the targeting of FP-IONP-COOH/DOX. The cumulative release of DOX at 48 h could be as high as 82 %, whereas the accumulated release of FP-IONP-COOH/DOX at 48 h was only 48 %, and was able to continuously release for more than 120 h, demonstrating its good sustained release in vivo.

Interaction analysis between small molecules and RNA as well as structure determination of RNA–small molecule complexes will be the clues to search for compounds that bind to specific mRNA or non-coding RNA in drug discovery. In this study, the RNA-binding ability of a fluoroquinolone derivative, KG022, was examined against single-residue bulge-containing hairpin RNAs as RNA models. Nuclear magnetic resonance analysis indicated that KG022 interacts with the RNAs in the vicinity of the bulge residue, with preferring C and G as the bulge residues. The solution structures of the RNA–KG022 complexes showed that the KG022 binds to the RNAs at the bulge-out regions. Each substituent in KG022 interacts with specific position of RNAs around the bulge-out region probably contributing the specificity of the binding. This work provides a novel member for the RNA-targeted small molecules.

International audience; Zeolite Y and its ultra-stabilized hierarchical derivative (USY) are the most widely used zeolite-based heterogeneous catalysts in oil refining, petrochemisty, and other chemicals manufacturing. After almost 60 years of academic and industrial research, their resilience is unique as no other catalyst displaced them from key processes such as FCC and hydrocracking. The present study highlights the key difference leading to the exceptional catalytic performance of USY versus the parent zeolite Y in a multi-technique study combining advanced spectroscopies (IR and solid-state NMR) and molecular modeling. The set of results highlights a hitherto unreported proton transfer involving inaccessible active sites in sodalite cages that contributes to the exceptional catalytic performance of USY.

Electrochemical transformations of DDT into oxygen-incorporated products, amides and esters, catalyzed by the B12 derivative, heptamethyl cobyrinate perchlorate, have been developed under aerobic c...

5-(Chloromethyl)furfural (CMF) is a cellulose derivative of increasing appeal as a renewable platform molecule. Although its role as an electrophile has been broadly studied, little is known about ...

International audience; Investigating the possibility of a straightforward formation of tetrazoline or tetrazolidine structures, the reactivity of a tetrazole derivative towards reducing conditions has been studied. The catalytic hydrogenation of 1,1’-dimethylbistetrazole (DMBT) was carried out using various catalysts (Pd/C, Pt/C, Rh/C, Pd/Pt/C, Lindlar, PtO2 and Raney Ni) over a wide range of hydrogen pressure (35–150 bar) and a temperature range from 20 to 60 °C. This exhaustive study enabled to find the optimal conditions for DMBT hydrogenation and to suggest a plausible reaction mechanism. The chemical reduction of DMBT was conducted using several hydrides (BH3, NaBH4, DIBAL and LiAlH4). The reduction products were identified subsequently to conditions optimizing. The suggested reaction mechanism, featuring a retro-[3 + 2]-cycloaddition, was validated by both experimental and theoretical approaches.

The synthesis and crystal structure of pyridine-3-carbaldehyde-N-ethylthiosemicarbazone (3-pytscH-NHEt) 1, and its CuI complex of stoichiometry, [CuCl(3-pytscH-NHEt)(PPh3)2] 2, studied using single crystal X-ray crystallography, are reported in this paper. Crystal data: 1, monoclinic, P21/n, a = 6.6322(3), b = 21.1200(8), c = 7.2989(3) A; β = 91.883(4), T = 173(2), R factor = 0.0457; 2: triclinic, P-1, a = 19.3600(5), b = 20.6241(6), c = 23.8015(6) A,α = 92.647(2), β = 104.388(2), γ = 114.377(3), R factor = 0.0662. The thio-ligand, as a neutral entity, is coordinating to Cu through its S donor atom in complex 2. It has exhibited an unusual feature of forming four independent molecules (A, B, C, D) in the unit cell, with minor differences in the bond angles / distances / torsion angles. The geometry of each molecule of 2 is distorted tetrahedral. Crystal packing, as well as Infrared, electronic absorption and proton NMR spectroscopic studies, are also reported. Copper compound 2 represents the first example of a structurally studied copper coordination compound of 3-pyridyl based thiosemicarbazones. Copper(I) chloride with pyridine-3-carbaldehyde-N-ethylthiosemicarbazone and PPh3 in CH3CN yielded a copper compound, 2 (Green-Cl, blue-N; aqua-Cu, orange-S, magneta-P).