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Objective: Chitin a natural polymer is abundant in several sources such as shells of crustaceans, mollusks, insects, and fungi. Several possible attempts have been made to recover chitin because of its importance in biomedical applications in various forms such as hydrogel, nanoparticles, nanosheets, nanowires, etc. Among them, deep eutectic solvents have gained much consideration because of their eco-friendly and recyclable nature. However, several factors need to be addressed to obtain a pure form of chitin with a high yield. The development of an innovative system for the production of quality chitin is of prime importance and is still challenging. Methods: The present study intended to develop a novel and robust approach to investigate chitin purity from various crustacean shell wastes using deep eutectic solvents. This investigation will assist in envisaging the important influencing parameters to obtain a pure form of chitin via a machine learning approach. Different machine learning algorithms have been proposed to model chitin purity by considering the enormous experimental dataset retrieved from previously conducted experiments. Several input variables have been selected to assess chitin purity as the output variable. Results: The statistical criteria of the proposed model have been critically investigated and it was observed that the results indicate XGBoost has the maximum predictive accuracy of 0.95 compared with other selected models. The RMSE and MAE values were also minimal in the XGBoost model. In addition, it revealed better input variables to obtain pure chitin with minimal processing time. Conclusion: This study validates that machine learning paves the way for complex problems with substantial datasets and can be an inexpensive and time-saving model for analyzing chitin purity from crustacean shells. [ABSTRACT FROM AUTHOR]

TheDES are formed by mixing a Hydrogen Bond Donor (HBD) and a Hydrogen Bond Acceptor (HBA) in appropriate molar ratios. These solvents have been shown to enhance drug solubility, permeability, and delivery. The main objective of the present article is to review these advantages of TheDES. TheDES show unique properties, such as low toxicity, biodegradability, improved bioavailability and enhanced drug delivery of poorly soluble active pharmaceutical ingredients. They are also biocompatible in nature which makes them a promising candidate for various therapeutic applications, including drug formulations, drug delivery and other biomedical uses. The development and utilization of TheDES shows significant advancement in pharmaceutical research, providing new opportunities for improving drug delivery. The current study was carried out by conducting a systematic literature review that identified relevant papers from indexed databases. Numerous studies and research are cited and quoted in this article to demonstrate the effectiveness of TheDES in enhancing drug solubility, permeability, and delivery. All chosen articles were selected considering their significance, quality, and approach to addressing issues. As a result, various TheDES were identified that can be formulated in different ways: one component can act as a vehicle for an API, either HBD or HBA can be an API, both HBD and HBA can be APIs, or the individual components of DES are not therapeutically active but the resulting DES possesses therapeutic activity. Additionally, TheDES were also recognized to enhance drug delivery and solubility for different APIs, including NSAIDs, anesthetic drugs, antifungals, and others. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DESs) represent a promising solution for gas capture within existing industrial frameworks, requiring minimal retrofitting. This review explores the gas absorption and solubility capabilities of diverse DESs, emphasising their tunability through variations in hydrogen bond donors (HBDs), hydrogen bond acceptors (HBAs), and molar mixing ratios. The introduction of water marginally enhances gas absorption, while increased HBD ratios and elevated temperatures lead to decreased gas solubility. Conversely, pressure elevation improves gas solubility in DES. The alkyl chain length of the DES HBA correlates with gas solubility, attributed to an increase in DES free volume. Other factors like ionicity and alkalinity of DESs were reported to enhance gas capture. This review also discusses the selectivity of DESs in capturing distinct gases, unveiling a robust hydrogen-bond supramolecular network as the key determinant for high gas selectivity. Examples include effective NH3 capture within NH3/CO2 mixtures and targeted SO2 capture in CO2/SO2 mixtures. The absorption mechanism of gaseous pollutants using DES is both physical and chemical, with physical absorption playing a dominant role. During the regeneration of DESs, the stability and volatility of DESs are significant factors to consider. These insights underscore the potential of DESs in tailoring selective gas capture strategies, providing avenues for future research and practical applications in environmental and industrial contexts.

Moringa oleifera is a plant native to India and its flowers are an excellent source of phenols, flavonoids, and antioxidants. DES (Deep Eutectic Solvents) based solvents have a vast majority of benefits, such as they are non-toxic, green solvents, with a highly efficient method of extraction of phenolic, antioxidant, and flavonoid compounds. DES solvents are made by combining two solvents, out of which one must be a hydrogen bond donor (HBD) and another must be a hydrogen bond acceptor (HBA) whereas, combining these two types reduces the melting point of the solvents. Six different types of DESs combinations were used in different ratios, for the optimization of the extraction process. The six combinations used were ChCl-Gly, ChCl-MA, ChCl-LA, ChCl-Glu, Pro-Gly, and Pro-LA. Total phenolic content, flavonoid content, antioxidant activity, lipase activity and glucose uptake assay of Moringa oleifera flower (MOFs) extracts were calculated in vitro at different temperatures ranging from 50 to 80 ℃ by using the statistical tool Anova single factor. Maximum yield, of phytochemicals were found at 70 ℃ with the DES combination Pro-Gly in 1:2 M ratio where phenolic content (32.4 mg GAE/g DW), Flavonoid content (42.1 mg QE/g DW), and antioxidant activity (65.82 %).

[Display omitted] • P(StDVB-[C 4 vim][BF 4 ]) with multiple hydrogen bond receptors was synthesized by the double emulsion interfacial polymerization method. • The multiple hydrogen bond receptors could form multiple hydrogen bonds with the ACT. • The multiple hydrogen bonds were proposed as the main driving forces for adsorbing P(StDVB-[C 4 vim][BF 4 ]) and ACT. The efficient adsorption of acteoside (ACT) was essential for the development and utilization of the active ingredients of Cistanche tubulosa. In this study, the adsorbent of hydrophilic imidazole polyionic liquids P(StDVB-[C 4 vim][BF 4 ]) was synthesized based on a double emulsion interfacial polymerization method to adsorb hydrophilic ACT. The as-prepared P(StDVB-[C 4 vim][BF 4 ]) showed an excellent adsorption performance, and the adsorption capacity and selectivity were 114.31 mg/g and 4.31, respectively. This was mainly attributed to as follows: firstly, P(StDVB-[C 4 vim][BF 4 ]) possessed multiple hydrogen bond receptors due to the introduction of functional monomer [C 4 vim][BF 4 ]. The multiple hydrogen bond receptors provided the F atoms and N atoms to form multiple hydrogen bonds with the ACT, realizing the efficient adsorption of ACT. Secondly, the hierarchical porous structure had plenty of micro-mesopores and macropores. The micropores prefer screened small molecules, enhancing the selective adsorption of ACT, the mesoporous pores greatly improved the diffusion ability of ACT in the pores of P(StDVB-[C 4 vim][BF 4 ]), and the macropores reduced transportation restrictions and facilitated the entry of ACT. Finally, the P(StDVB-[C 4 vim][BF 4 ]) contained hydrophilic imidazole group, enhancing the affinity between P(StDVB-[C 4 vim][BF 4 ]) and ACT. Thus, P(StDVB-[C 4 vim][BF 4 ]) can effectively adsorb ACT. The multiple hydrogen bonds were suggested as the major driving forces for adsorbing P(StDVB-[C 4 vim][BF 4 ]) and ACT. In addition, P(StDVB-[C 4 vim][BF 4 ]) was conveniently regenerated up to 6 times. Therefore, the P(StDVB-[C 4 vim][BF 4 ]) had potential application for adsorbing active ingredients of natural products. [ABSTRACT FROM AUTHOR]

The harmful effects of endocrine disrupting chemicals (EDCs) to humans and other organisms in the environment have been well established over the years, and more studies are ongoing to classify other chemicals that have the potential to alter or disrupt the regular function of the endocrine system. In addition to toxicological studies, analytical detection systems are progressively being improved to facilitate accurate determination of EDCs in biological, environmental and food samples. Recent microextraction methods have focused on the use of green chemicals that are safe for analytical applications, and present very low or no toxicity upon disposal. Deep eutectic solvents (DESs) have emerged as one of the viable alternatives to the conventional hazardous solvents, and their unique properties make them very useful in different applications. Notably, the use of renewable sources to prepare DESs leads to highly biodegradable products that mitigate negative ecological impacts. This review presents an overview of both organic and inorganic EDCs and their ramifications on human health. It also presents the fundamental principles of liquid phase and solid phase microextraction methods, and gives a comprehensive account of the use of DESs for the determination of EDCs in various samples. [Display omitted] • Endocrine disruptor compounds classified under major chemical groups. • Brief overview of liquid phase microextraction methods. • Composition, categories, characterization, and mechanism of deep eutectic solvents as extractants. • Application of DESs for the determination of organic and inorganic endocrine disruptors. [ABSTRACT FROM AUTHOR]

In this work, cobalt-ZIF catalysts were synthesized by water-based synthesis methods. Various hydrogen bond acceptor (tetramethylammonium bromide (TMAB), tetraethylammonium bromide (TEAB), tetrapropylammonium bromide (TPAB), tetrabutylammonium bromide (TBAB) and trimethylphenylammonium bromide (TMPAB)) were co-added during cobalt-ZIF catalyst synthesis procedures to promote the deprotonation of 2-methyl imidazole and the deprotonated 2-methyl imidazole was then further coordinated with cobalt ion to form a ZIF framework. Co-addition of TMPAB during synthesis resulted in 3D imperfect rhombic dodecahedrals with high surface area (432.3 m2/g), while, the rest of used hydrogen bond acceptors (TMAB, TEAB, TPAB and TBAB) provided 2D ZIF-L structure with relatively small surface area and pore volume. All synthesized cobalt-ZIF with different structures and morphologies were used as a catalyst for H 2 generation by NaBH 4 hydrolysis reaction. It was found that all 2D cobalt-ZIF structures exhibited higher hydrogen production rate than that of the 3D imperfect rhombic dodecahedral structure. This can be explained by the cushion-shaped cavity of a two-dimensional framework exhibiting higher flexibility which can promote more diffusion of reactants than the tetrahedral structure of a 3D-framework. X-ray absorption spectroscopy was used to investigate the electronic state of cobalt and to monitor the changing of cobalt probe atom during hydrolysis reaction. The electronic state of cobalt for all catalysts was Co2+ with the same tetrahedral symmetry. The lowering of pre-edge peaks of cobalt K edge XANES spectra during hydrolysis reaction indicated to distortion of the symmetry which is related to the reduction of the catalytic performance. [Display omitted] • Cobalt-ZIF catalysts were synthesized by using water as a medium. • Various QAS were coadded during ZIF synthesis to promote deprotonation of 2-MeIM. • Different QAS coaddition resulted in different structure and morphology of ZIF. • 2D-ZIF showed higher H 2 production rate for NaBH 4 hydrolysis than 3D structure. • Lowering of pre-edge Co XANES spectra indicted to reduction of catalytic activity. [ABSTRACT FROM AUTHOR]

The synthesis of a series of 1-azafagomine derivatives that are tethered with five- and six-membered 1,2-annulated ring systems is described. These compounds were used in order to explore whether a hydrogen-bond acceptor group on the carbon atom corresponding to the glycosidic oxygen is able to interact with the catalytic acidic residue of β-glucosidase. The hydrogen-bond acceptor group was installed at various positions on the annulated ring system making it possible to study the effect of altering the position of this group. [ABSTRACT FROM AUTHOR]

[Display omitted] The epigenetic regulation of the protein bromodomain-containing protein 4 (BRD4) has emerged as a compelling target for cancer treatment. In this study, we outline the discovery of a novel BRD4 inhibitor for melanoma therapy. Our initial finding was that benzimidazole derivative 1 , sourced from our library, was a powerful BRD4 inhibitor. However, it exhibited a poor pharmacokinetic (PK) profile. To address this, we conducted a scaffold-hopping procedure with derivative 1 , which resulted in the creation of benzimidazolinone derivative 5. This new derivative displayed an improved PK profile. To further enhance the BRD4 inhibitory activity, we attempted to introduce hydrogen bond acceptors. This indeed improved the activity, but at the cost of decreased membrane permeability. Our search for a potent inhibitor with desirable permeability led to the development of tricyclic 18. This compound demonstrated powerful inhibitory activity and a favorable PK profile. More significantly, tricyclic 18 showed antitumor efficacy in a mouse melanoma xenograft model, suggesting that it holds potential as a therapeutic agent for melanoma treatment. [ABSTRACT FROM AUTHOR]

The preparation of natural deep eutectic solvents (NADESs) from cheap and readily available raw materials is reported. In this work, we have considered mixtures of choline chloride (CC) or betaine (Bet) with 3 sugar molecules (glucose (Glu), xylose (Xyl) and sucrose (Suc)) and 2 carboxylic acids (citric (CA) and tartaric (Tart) acids). The formation of NADESs was investigated by polarized optical microscopy (POM) and differential scanning calorimetry (DSC). The CC mixtures give origin to NADESs for 1:1 M ratio with the sugar molecules and for 2:1, 1:1 and 1:2 with the carboxylic acids, while Bet mixtures only formed NADES with the carboxylic acids. The effect of water content (up to 5% (wt.%)) and temperature in conductivity and rheology were characterized. The NADESs were found to be non-thixotropic, Newtonian liquids with high viscosity, decreasing with increasing temperature and water content. The conductivity is limited by charge carrier mobility, thus increasing with water content and temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrogen bond acceptor lined hydrogel electrolyte is proposed for Zn metal anodes of wearable AZIBs. • The hydrogen bond acceptor lined hydrogel electrolyte with excellent mechanical properties and high ionic conductivity. • The free-water activity can be reduced to inhibit water-induced side reactions. • Regulation of Zn (0 0 2) deposition and high-performance aqueous zinc-ion battery is achieved. Flexible aqueous Zn-ion batteries (AZIBs) are recognized as a prospective energy storage device benefiting from their high security, low price and competitive electrochemical performance. But there are two drawbacks that seriously hinder the actual utilization of AZIBs, which are the dendrite growth of zinc anodes and the freezing of liquid electrolytes at subzero temperatures. To this end, functional three-dimensional network hydrogel electrolyte lined with hydrogen bond acceptor (denoted as PDC-20 gel electrolyte) was designed to address this challenge. The hydrogen bond acceptor dimethyl sulfoxide (DMSO), H 2 O and polymer chains can form a ternary hydrogen bond to improve mechanical performances of the hydrogel electrolyte. Meanwhile, DMSO breaks the hydrogen bond of water, greatly reduces the freezing point of the hydrogel electrolyte, reconstructs the solvation structure of Zn2+ in the hydrogel, optimizes the deposition kinetics of Zn2+, and ultimately achieves effective inhibition of Zn dendrites and side reactions. Therefore, the Zn//Zn symmetry battery with PDC-20 gel electrolyte can achieve a stable plating/stripping process for 1300 h at 2 mA cm−2 with set capacity of 2 mAh cm−2. The assembled Zn//MnO 2 /CNT battery has a large specific capacity of 238.4 mAh/g and a high cycle stability of 5000 cycles at 2 A/g at room temperature. A high ion conductivity of 2.82 mS cm−1 and a specific capacity of 160.5 mAh/g were still achieved at −20 °C. This study offers an inspiring strategy and good feasibility to design high performance antifreeze flexible batteries by introducing hydrogen bond acceptor. [ABSTRACT FROM AUTHOR]

The critical challenge being faced by our current modern society on a global scale is to reduce the surging effects of climate change and global warming, being caused by anthropogenic emissions of CO 2 in the environment. Present study reports the surface driven adsorption potential of deep eutectic solvents (DESs) surface functionalized cerium oxide nanoparticles (CeNPs) for low pressure CO 2 separation. The phosphonium based DESs were prepared using tetra butyl phosphoniumbromide as hydrogen bond acceptor (HBA) and 6 acids as hydrogen bond donors (HBDs). The as-developed DESs were characterized and employed for the surface functionalization of CeNPs with their subsequent utilization in adsorption-based CO 2 adsorption. The synthesis of as-prepared DESs was confirmed through FTIR measurements and absence of precipitates, revealed through visual observations. It was found that DES6 surface functionalized CeNPs demonstrated 27% higher adsorption performance for CO 2 capturing. On the contrary, DES3 coated CeNPs exhibited the least adsorption progress for CO 2 separation. The higher adsorption performance associated with DES6 coated CeNPs was due to enhanced surface affinity with CO 2 molecules that must have facilitated the mass transport characteristics and resulted an enhancement in CO 2 adsorption performance. Carboxylic groups could have generated an electric field inside the pores to attract more polarizable adsorbates including CO 2 , are responsible for the relatively high values of CO2 adsorption. The quadruple movement of the CO 2 molecules with the electron-deficient and pluralizable nature led to the enhancement of the interactive forces between the CO 2 molecules and the CeNPs decorated with the carboxylic group hydrogen bond donor rich DES. The current findings may disclose the new research horizons and theoretical guidance for reduction in the environmental effects associated with uncontrolled CO 2 emission via employing DES surface coated potential CeNPs. [ABSTRACT FROM AUTHOR]

During the lead generation and optimization of PARP inhibitors blocking centrosome clustering, it was discovered that increasing hydrogen bond acceptor (HBA) strength improved cellular potency but led to elevated Caco2 and MDR1 efflux and thus poor oral bioavailability. Conversely, compounds with lower efflux had reduced potency. The project team was able to improve the bioavailability by reducing efflux through systematic modifications to the strength of the HBA by changing the electronic properties of neighboring groups, whilst maintaining sufficient acceptor strength for potency. Additionally, it was observed that enantiomers with different potency showed similar efflux, which is consistent with the promiscuity of efflux transporters. Eventually, a balance between potency and low efflux was achieved for a set of lead compounds with good bioavailability which allowed the project to progress towards establishing in vivo pharmacokinetic/pharmacodynamic relationships. [ABSTRACT FROM AUTHOR]

Various inhibitors have been developed for neuraminidase but resistance against these drugs in many viral strains makes it an advantageous and interesting task to discover compounds which can be more promising in preventing viral infection through neuraminidase. Virtual screening methods have been proved as an efficient in silico approach for drug discovery processes. In the present study, we used ligand based virtual screening process for identifying potent inhibitors against viral neuraminidase enzyme. The approach utilized in this study has been successful in identifying 15 compounds which may be potential inhibitors of neuraminidase. These compounds were screened via three screening platforms (MVD, PyRx, and FRED) by setting oseltamivir as reference compound, which is an FDA approved drug against influenza virus. These compounds were then filtered by their in silico ADME/T (Absorption, Distribution, Metabolism, Excretion, and Toxicity) values and only 12 of them were found to have comparatively better results. The results of the present study are reported herein so that researchers, who are having required laboratory facilities for synthesizing drugs, can utilize findings of this study for developing new drugs against influenza with better efficacy. [ABSTRACT FROM AUTHOR]

[Display omitted] • DFT calculations towards finding suitable HBD and HBA for the formation of redox and radiation stable DES. • Phase diagram to depict the molar ratio of the constituents in the new DES. • Stabilization energy calculation of the predicted new DES. • Experimental synthesis and characterization of the DES predicted from computational calculations. • Radiation stability study and by-product analysis of the as synthesized DES under gamma irradiation. A redox and radiation stable DES has been predicted based on the fundamental electronic properties such as energy gap, ionization potential and electron affinity computed applying suitable density functionals in combination with 6-311++G(d,p) set of atomic basis functions. A selected series of optimized hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) has been screened using density functional theory (DFT). The long range corrected density functionals; ωB97XD and LC-BLYP are found to be cost effective and appropriate towards orbital energy gap calculations of such systems. Choline acetate and malonic acid appeared to be the most appropriate combination among those studied for formation of a chemical and radiation stable DES. Theoretically constructed phase diagram using Gibbs free energy minimization technique is applied to suggest the eutectic point and eutectic composition of the recommended DES. Stabilization energy calculations following electronic structure support the phase diagram data denoting formation of a stable eutectic with 1:2 stoichiometry. Density, viscosity, differential scanning calorimetry (DSC) and Fourier transform infra-red (FTIR) experiments have been carried out with this synthesized DES. Measured glass transition temperature (−75 °C) is observed to be lower than the theoretical eutectic point (−40 °C) indicating strong interspecies interaction within the medium. Experimental FTIR analysis gives an idea of the type and number of H-bonds present within the DES whereas computationally optimized 1:2 geometry identifies the specific H-bonds along with their distances. Irradiation of this new DES has been conducted at a constant dose of 100 kGy to observe the extent of degradation. UV–Vis and FTIR analysis does not denote generation of any new species within the liquid phase upon irradiation, however the yields of the gaseous by-products have been quantified by Gas Chromatography (GC). [ABSTRACT FROM AUTHOR]

The correct positioning and orientation of an hydrogen bond acceptor (HBA) in the tail portion of the biaryl series of CRTh2 antagonists is a requirement for long receptor residence time. The HBA in combination with a small steric substituent in the core section (R core ≠ H) gives access to compounds with dissociation half-lives of ⩾24 h. [ABSTRACT FROM AUTHOR]

Abstract: Prompted by the role of PDE5 and its closely associated cAMP and cGMP in hypertension, we have attempted to discover novel PDE5 inhibitors through ligand based virtual screening. Rigorously validated model comprising of one HBA, one HY and one RA was used as a query to search the NCI database leading to retrieval of many compounds which were screened on the basis of estimated activity, fit value and Lipinski’s violation. Selected compounds were subjected to docking studies which resulted into visualization of potential interaction capabilities of NCI compounds in line to pharmacophoric features. Finally three compounds were subjected to in vitro evaluation using the isolated rat aortic model. The results showed that all three compounds are potent and novel PDE5 inhibitors with vasodilatory activity range from 10−2 to 10−5 M. [Copyright &y& Elsevier]

• Green solvent ionic liquids — [BMIM][OTF], [EMIM][OTF] and [EMIM][DCA] are used as extraction solvents. • The liquid–liquid equilibrium between ionic liquids acetone and isopropyl ether in ternary system is studied. • Correlation is made to fit the experimental measurements using the NRTL model. • The extraction mechanism of σ-profiles, total charge density, bond length, interaction energy and deformation charge density is analyzed. Selecting green and efficient extractive solvents are the inevitable requirement of sustainable development. Ionic liquids as green solvents are widely used in the separation of organic substance. In this manuscript, ionic liquids are used as extractive solvents to separate isopropyl ether-acetone system. The selected ionic liquids are 1-ethyl-3-methylimidazole dinitrile amine [EMIM][DCA], n-butyl-3-methylimidazole trifluoromethane sulfonate [BMIM][OTF], 1-ethyl-3-methylimidazole trifluoromethane sulfonate [EMIM][OTF]. Firstly, the relation between H-bonding donor and H-bonding acceptor is description by COSMO-SAC model based on the extraction mechanism. After that the experiments of liquid–liquid equilibrium are conducted at T = 298.15 K and P = 101.325 kPa, and the liquid–liquid equilibrium data are correlated by NRTL model. The results indicate that the model has a good correlation with the experimental results. Finally, the extraction mechanism is discussed at micro scale. The H-bonding interaction between ionic liquids and acetone, including total charge density, bond length, deformation charge density and interaction energy, is determined by quantum chemistry calculation. The quantum chemical calculation and experimental process provide theoretical guidance for the highly efficient separation of acetone - isopropyl ether binary system. [ABSTRACT FROM AUTHOR]

Abstract: A novel series of α4β2 nAChR agonists lacking common pyridine or its bioisosteric heterocycle have been disclosed. Essential pharmacophoric elements of the series are exocyclic carbonyl moiety as a hydrogen bond acceptor and secondary amino group within diaza- or azabicyclic scaffold. Computer modeling studies suggested that molecular shape of the ligand also contributes to promotion of agonism. Proof of concept for improving working memory performance in a novel object recognition task has been demonstrated on a representative of the series, 3-propionyl-3,7-diazabicyclo[3.3.0]octane (34). [Copyright &y& Elsevier]

Abstract: In this work, the hydrogen bond formation ability of cation and anion of the ILs was determined by using the solvatochromic method and was found to be responsible for their catalytic activity in the Knoevenagel reactions. The enhancement in the hydrogen bond donor ability of the cations and the hydrogen bond acceptor ability of the anions can both lead to the increase in the catalytic activity of the ILs. From the proposed reaction mechanism, it was deduced that the cations of the ILs can form hydrogen bond with aldehyde to activate the C electrophile, and the anions of the ILs can promote active methylene compound to produce carboanion as nucleophile, showing dual function activation effect in the catalytic processes. In addition, the optimized N,N-dimethylethanolamnium acetate as dual function activator for the Koevenagel reactions benefits from wide substrates tolerance, ambient reaction temperature, easy work-up procedure, and easy reuse of the IL. [Copyright &y& Elsevier]

Abstract: A directing/protecting group designed for regioselective functionalization of partially-protected glucopyrannosides has been successfully used to prepare disaccharides in high yields. Most importantly, it has been demonstrated that highly regioselective and stereoselective glycosylation can be achieved when disarmed donors are employed. This study demonstrates the ability of directing/protecting group to induce regioselective glycosylation of carbohydrates and opens the field to the design of other DPGs for other monosaccharides. [Copyright &y& Elsevier]

Abstract: Sodium 10-undecenyl sulfate (SUS), sodium 10-undecenyl leucinate (SUL) and their five different mixed micelles at varied percent mole ratios were prepared. The critical micelle concentration (CMC), C20, γCMC, partial specific volume, methylene group selectivity, mobilities and elution window were determined using a variety of analytical techniques. These surfactant systems were then evaluated as novel pseudostationary phases in micellar electrokinetic chromatography (MEKC). As a commonly used pseudostationary phase in MEKC, sodium dodecyl sulfate (SDS) was also evaluated. The CMC values of SUS and SUL were found to be 26 and 16mM, respectively, whereas the CMC of mixed surfactants was found to be very similar to that of SUL. The C20 values decreased dramatically as the concentration of SUL is increased in the mixed micelle. An increase in SUL content gradually increased the methylene group selectivity making the binary mixed surfactants more hydrophobic. Linear solvation energy relationships (LSERs) and free energy of transfer studies were also applied to predict the selectivity differences between the surfactant systems. The cohesiveness and the hydrogen bond acidic character of the surfactant systems were found to have the most significant influence on selectivity and MEKC retention. The SUS and SDS showed the strongest while SUL showed the weakest hydrogen bond donating capacity. The basicity, interaction with n and π-electrons of the solute and dipolarity/polarizability were the least significant factors in LSER model for the surfactant systems studied. Free energies of transfer of selected functional groups in each surfactant systems were also calculated and found to be in good agreement with the LSER data. [Copyright &y& Elsevier]

Protonacceptor properties of the HOO radical were investigated previously by means of ab initio as well as topological Atoms in Molecules (AIM) and Electron Localization Function (ELF) methods. It was pointed out that in the radical there are three nonequivalent positions most susceptible to protonation, and on this basis three structures of possible hydrogen bonded complexes were proposed. Results reported in the present article concern all possible 1:1 complexes formed by HCl and HOO molecules, and fully confirm suppositions given on the basis of the above-mentioned investigations. There are three various complexes referring to the local minima, and the transition structure predicted by topological methods has been found as well. The cyclic structure appeared to be the most stable one, which confirms conclusions given in the experimental article. Apart from structure optimization, harmonic as well as anharmonic spectra of the complexes have been simulated. Anharmonicity of H&bond;Cl stretching vibration was of special interest, as the frequency of this vibration characterizes the Cl&bond;H · · · O hydrogen bond in these complexes. To obtain values of these frequencies the one-dimensional Hamiltonian has been diagonalized numerically. The potential for this Hamiltonian has been taken from a set of single-point scanning of the part of the Potential Energy Surface (PES) connected with this vibration. The potential calculated on the MP2 level leads to the result close to the experimental value, whereas the B3LYP method is inappropriate for the purpose of PES investigation of these complexes. © 2005 Wiley Periodicals, Inc. J Comput Chem 27: 287–295, 2006 [ABSTRACT FROM AUTHOR]

Neurotoxic organophosphorous compounds are known to modulate their biological effects through the inhibition of a number of esterases including acetylcholinesterase (AChE), the enzyme responsible for the degradation of the neurotransmitter acetylcholine. In this light, molecular modeling studies were performed on a collection of organophosphorous acetylcholinesterase inhibitors by the combined use of conformational analysis and 3D-QSAR methods to rationalize their inhibitory potencies against the enzyme. The Catalyst program was used to identify the structural features in the group of 8 inhibitors whose IC50 values ranged from 0.34 nM to 1.2 μM. The 3-D pharmacophore models are characterized by at least one hydrogen bond acceptor site and 2–3 hydrophobic sites and demonstrate very good correlation between the predicted and experimental IC50 values. Our models can be useful in screening databases of organophosphorous compounds for their neurotoxicity potential via the inhibition of acetylcholinesterase. Also, the pharmacophores offer an additional means of designing AChE inhibitors as potential therapeutic agents for central nervous system diseases. [ABSTRACT FROM PUBLISHER]

Three ternary mixtures composed by choline chloride (ChCl), ethylene glycol (EG), and a second hydrogen bond donor (HBD) as ethanol (A), 2-propanol (B), and glycerol (C) were studied in terms of composition related to the band gap energy (BGE). A Design of Experiments (DoE) approach, and in particular a Simple Lattice three-components design, was employed for determining the variation of the BGE upon the composition of each system. UV-VIS analysis and subsequent Tauc plot methodology provided the data requested from the DoE, and multivariate statistical analysis revealed a drop of the BGE in correspondence to specific binary compositions for systems A and B. In particular, a BGE of 3.85 eV was registered for the mixtures ChCl/EtOH (1:1) and ChCl/2-propanol (1:1), which represents one of the lowest values ever observed for these systems. [ABSTRACT FROM AUTHOR]

We previously identified a novel series of indolinylpyrimidine derivatives exemplified by 2 in Figure 1, which is an indoline based derivative, as potent GPR119 agonists. Despite the attractive potency of 2, this compound inhibited the human ether-a-go-go-related gene (hERG) K+ channel. We elucidated crucial roles of the methylsulfonyl group of 2 in its interaction with the hERG channel and the GPR119 receptor, presumably as a hydrogen bond acceptor (HBA). To remove the undesirable hERG inhibitory activity, a strategy was implemented to arrange an HBA on a less conformationally flexible framework at the indoline 5-position instead of the methylsulfonyl group. This successfully led to the discovery of a piperidinone ring as a desirable motif at the indoline 5-position, which could minimize hERG liability as shown by 24b. Further optimization focused on the reduction of lipophilicity in terms of more favorable drug-like properties. Consequently, the introduction of a hydroxy group at the 3-position of the piperidinone ring effectively reduced lipophilicity without compromising GPR119 potency, resulting in the identification of (3 S)-3-hydroxy-1-{1-[6-({1-[3-(propan-2-yl)-1,2,4-oxadiazol-5-yl]piperidin-4-yl}oxy)pyrimidin-4-yl]- 2,3-dihydro-1 H -indol-5-yl}piperidin-2-one ((S)-29) as a novel, potent, and orally bioavailable GPR119 agonist with a well-balanced profile. The pharmacological effects of this compound were also confirmed after single and chronic oral administration in diabetic animal models. [ABSTRACT FROM AUTHOR]

The optical properties of nine choline-based Deep Eutectic Solvents (DESs) of the type choline+X− (X− = chloride or acetate)/Y (Y = ethylene glycol, glycolic or levulinic acid) were studied by measuring their band gap through the UV-VIS-based Tauc method. All the considered systems showed a direct optical transition. A correlation between band gap and eutectic composition was discovered by plotting the variation of the band gap versus the molar fraction of choline+X−/Y in the parent systems containing 10 wt% of H 2 O. The main parameters influencing the energy of the optical transition in these "Deep Band Gap Systems" (DeBaGS) where studied through Design of Experiments (DoE) combined with multivariate analysis. The effect on the band gap of the anion (chloride or acetate), the acid (levulinic or glycolic), the water, and the stirring time, considered as single factor or in combination was clarified. Thus a multivariate model was implemented through surface responding analysis which allows engineering such kind of systems and opening to further applications in material science. Unlabelled Image • The band gap energy of molecular systems containing hydrogen donors and acceptors can be customized. • Water addition in binary DESs has a not-negligible effect on the optical properties even at low concentrations. • The preparation time of DES-like systems affects their optical properties. [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) have been proposed as phase-forming compounds of aqueous biphasic systems (ABS). However, due to DES nature and the high water content of the ABS, their nature and behavior remains controversial. To foster the understanding of DES-based ABS, the present work uses the relative hydrophilicity of the hydrogen bond donor (HBD) as a descriptor to clarify its role on ABS formation and phase properties. Dipotassium phosphate (K 2 HPO 4)-based ABS phase diagrams composed of cholinium chloride ([N 111(2OH) ]Cl), as hydrogen bond acceptor (HBA), and several HBD (alcohols and sugars) were compared in molality units and the saturation solubility point for each binodal curve determined. The results here reported establish the HBD role as function of its relative hydrophilicity: very hydrophilic HBD act only as an adjuvant in the formation of ABS; HBD of intermediate hydrophilicity influence the ABS formation; while the most hydrophobic HBD tend to form organic-aqueous two-phase systems, where the HBA acts as an adjuvant to the system. Image 1 [ABSTRACT FROM AUTHOR]

3,7-Diazabicyclo[3.3.1]nonane (bispidine) based nicotinic acetylcholine receptor (nAChR) ligands have been synthesized and evaluated for nAChRs interaction. Diverse spacer motifs were incorporated between the hydrogen bond acceptor (HBA) part and a variety of substituted (hetero)aryl moieties. Bispidine carboxamides bearing spacer motifs often showed high affinity in the low nanomolar range and selectivity for the α4β2(∗) nAChR. Compounds 15, 25, and 47 with Ki values of about 1 nM displayed the highest affinities for α4β2(∗) nAChR. All evaluated compounds are partial agonists or antagonists at α4β2(∗), with reduced or no effects on α3β4(∗) with the exception of compound 15 (agonist), and reduced or no effect at α7 and muscle subtypes., (Copyright © 2013 Elsevier Ltd. All rights reserved.)