Benzyl Phenyl Research Articles

Oxidative amidation of benzyl alcohol, benzaldhyde, benzoic acid styrene and phenyl acetylene catalyzed by ordered mesoporous HKUST‐1‐Cu: Effect of surface area on oxidative amidation reaction

HKUST‐1‐Cu synthesized in the presence and absence of P‐123 trough solvotermal method. After characterization using some different microscopic and spectroscopic techniques such as XRD, FT‐IR, SEM, ICP, BET and TEM its catalytic activity was investigated in the oxidative coupling of benzyl alcohol, benzaldhyde, benzoic acid, styrene and phenyl acetylene with N,N‐dialkylformamides for the preparation of N,N‐dimethylformamides. Different derivatives of tertiary amides were synthesized in moderate to good yields in the presence of just ~0.28 mol% of this catalytic system. Reusability of the synthesized catalysts was examined and catalysts were reusable for 8 times without significant decrease in optimized conditions.

Effect of Metal Catalysts on Bond Cleavage Reactions of Lignin Model Compounds in Supercritical Water

Lignin depolymerization into its aromatic monomers is necessary for the valorization of lignocellulosic biomass, but cleavage of the C–O ether bonds and C–C bonds between the monomers is challenging. In this study, we investigated bond cleavage reactions of benzyl phenyl ether, diphenyl ether, and biphenyl, which served as models for lignin compounds with α–O–4, 4–O–5, and 5–5 linkages, respectively, by using various metal catalysts in supercritical water at 673 K and a water density of 0.5 g cm−3 without added hydrogen gas. Benzyl phenyl ether was decomposed without catalyst. We found that palladium, platinum, and rhodium catalysts supported on carbon showed activity for cleavage of the C–O ether bonds in benzyl phenyl ether and diphenyl ether but not for the bonds between the aromatic units of biphenyl. Using anisole as a model compound, we also found that methoxy groups, which are present in lignin containing coniferyl and sinapyl alcohol monomers, were converted into phenol groups or were decomposed. The reaction conditions described herein have great potential utility for the conversion of lignin, which can be decomposed and dissolved in supercritical water, into valuable aromatic compounds.

Mapping the Azolog Space Enables the Optical Control of New Biological Targets.

Photopharmacology relies on molecules that change their biological activity upon irradiation. Many of these are derived from known drugs by replacing their core with an isosteric azobenzene photoswitch (azologization). The question is how many of the known bioactive ligands could be addressed in such a way. Here, we systematically assess the space of molecules amenable to azologization from databases of bioactive molecules (DrugBank, PDB, CHEMBL) and the Cambridge Structural Database. Shape similarity scoring functions (3DAPfp) and analyses of dihedral angles are employed to quantify the structural homology between a bioactive molecule and the cis or trans isomer of its corresponding azolog (“azoster”) and assess which isomer is likely to be active. Our analysis suggests that a very large number of bioactive ligands (>40 000) is amenable to azologization and that many new biological targets could be addressed with photopharmacology. N-Aryl benzamides, 1,2-diarylethanes, and benzyl phenyl ethers are particularly suited for this approach, while benzylanilines and sulfonamides appear to be less well-matched. On the basis of our analysis, the majority of azosters are expected to be active in their trans form. The broad applicability of our approach is demonstrated with photoswitches that target a nuclear hormone receptor (RAR) and a lipid processing enzyme (LTA4 hydrolase).

Comparison of Kinetics and Activity of Ni‐Based Catalysts for Benzyl Phenyl Ether Catalytic Hydrogenolysis

The influence of the type of support [activated carbon (AC), HZSM‐5, and γ‐Al2O3] on the performance of Ni‐based catalysts for the catalytic hydrogenolysis (CH) of benzyl phenyl ether (BPE) is investigated. The properties of an Ni‐based catalyst are investigated using diverse characterization techniques. An Ni/AC catalyst exhibits the highest dispersion of Ni atoms by CO pulse. The kinetic studies show that the apparent activation energies (Ea) for CH of BPE increase in the order Ea (Ni/AC) < Ea (Ni/γ‐Al2O3) < Ea (Ni/HZSM‐5), and the initial turnover frequencies follow the order of Ni/AC (64 mol molNisurf −1 h−1) > Ni/γ‐Al2O3 (58 mol molNisurf −1 h−1) > Ni/HZSM‐5 (45 mol molNisurf −1 h−1). All these results prove that the CH activity of BPE is significantly affected by the type of support, and Ni/AC is the highest activity catalyst in CH of the C—O bond of BPE. Toluene and phenol are major products in CH of BPE at a relatively low hydrogen pressure and high temperature. Based on catalytic experiments, a reaction mechanism is proposed, which provides the theoretical basis for converting lignite into high‐value organic molecules.

Selective cleavage of C[sbnd]O bond in benzyl phenyl ether over Pd/AC at room temperature

Selectively cleaving the CO bonds in lignin to produce aromatic products are challenging problems. Currently, catalytic hydrogenolysis of CO bonds in lignin requires harsh conditions. Herein, selectively cleaving CO bond of benzyl phenyl ether (BPE) was studied over Pd/AC, Ru/AC and Ni/AC. Among these catalysts, Pd/AC efficiently cleaved CO bond in BPE under super mild conditions (25 °C, 2 h and 0.1 MPa H2). The products were toluene and phenol without hydrogenation of the aromatic ring. The main competitive step of hydrogenolysis and hydrogenation is sensitive to reaction temperature over Pd catalyst. A mild temperature is preferred for hydrogenolysis, since the H species nearby the oxygen atom are more strongly adsorbed than nearby the benzene rings. With the different H-donor solvents, the highest conversion of BPE was obtained in isopropanol. Based on the experiments, the reactions occurred via cleavage of the Caliphatic-O bond in BPE and the synergetic effects between the H from absorbed H2 on the surface of the Pd and the intermediates radicals of benzyl and phenoxy should be the key points to such an optimum result.

Effect of SiO2/Al2O3 ratios of HZSM-5 zeolites on the formation of light aromatics during lignite pyrolysis

In this study, the effects of HZSM-5 zeolites with different SiO2/Al2O3 ratios on the formation and distribution of light aromatics (mainly BTEXN) were systematically investigated by in situ pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), and model compounds were used to analyze the catalytic routes of HZSM-5 zeolites for the formation of light aromatics during the pyrolysis of coal. Results revealed that the role played by HZSM-5 zeolites for the catalytic upgrading of uncondensed coal tar from the pyrolysis of coal is strong related to the Brönsted and Lewis acid sites and pore structure. HZ-25 zeolite (HZSM-5 zeolite with a SiO2/Al2O3 mole ratio of 25) with a high content of Brönsted and Lewis acid sites exhibited the best promotion for the catalytic upgrading of coal tar during the pyrolysis of Coal A. Model compounds of anthracene, benzyl phenyl ether, and petroleum ether represented the condensed aromatic ring; C-O bridge bond, and aliphatic structure in coal, respectively, and BTEXN was generated over the HZSM-5 zeolite catalyst. HZ-25 zeolite with a higher content of acid sites and high specific surface area is prone to facilitating the formation of BTEXN during the pyrolysis of petroleum ether, anthracene and benzyl phenyl ether. Notably, the obtained results indicated that HZSM-5 zeolites exhibit a dual promoting role for the aromatization of aliphatic hydrocarbons and catalytic cracking of macromolecular fragments during the pyrolysis of coal.

Catalytic Cleavage of Ether Bond in a Lignin Model Compound over Carbon-Supported Noble Metal Catalysts in Supercritical Ethanol

Decomposition of lignin-related model compound (benzyl phenyl ether, BPE) to phenol and toluene was performed over carbon-supported noble metal (Ru, Pd, and Pt) catalysts in supercritical ethanol without supply of hydrogen. Phenol and toluene as target products were produced by the hydrogenolysis of BPE. The conversion of BPE was higher than 95% over all carbon-supported noble metal catalysts at 270 ° for 4 h. The 5 wt% Pd/C demonstrated the highest yield (ca. 59.3%) of the target products and enhanced conversion rates and reactivity more significantly than other catalysts. In the case of Ru/C, BPE was significantly transformed to other unidentified byproducts, more so than other catalysts. The Pt/C catalyst produced the highest number of byproducts such as alkylated phenols and gas-phase products, indicating that the catalyst promotes secondary reactions during the decomposition of BPE. In addition, a model reaction using phenol as a reactant was conducted to check the secondary reactions of phenol such as alkylation or hydrogenation in supercritical ethanol. The product distribution when phenol was used as a reactant was mostly consistent with BPE as a reactant. Based on the results, plausible reaction pathways were proposed.

Sulphide as a leaving group: highly stereoselective bromination of alkyl phenyl sulphides.

A conceptionally novel nucleophilic substitution approach to synthetically important alkyl bromides is presented. Using molecular bromine (Br2), readily available secondary benzyl and tertiary alkyl phenyl sulphides are converted into the corresponding bromides under exceptionally mild, acid- and base-free reaction conditions. This simple transformation allows the isolation of elimination sensitive benzylic β-bromo carbonyl and nitrile compounds in mostly high yields and purities. Remarkably, protic functionalities such as acids and alcohols are tolerated. Enantioenriched benzylic β-sulphido esters, readily prepared by asymmetric sulpha-Michael addition, produce the corresponding inverted bromides with high stereoselectivities, approaching complete enantiospecificity at -40 °C. Significantly, the reported benzylic β-bromo esters can be stored without racemisation for prolonged periods at -20 °C. Their synthetic potential was demonstrated by the one-pot preparation of γ-azido alcohol (S)-5 in 90% ee. NMR studies revealed an initial formation of a sulphide bromine adduct, which in turn is in equilibrium with a postulated dibromosulphurane intermediate that undergoes C-Br bond formation.

Efficient liquid-phase hydrogenolysis of a lignin model compound (benzyl phenyl ether) using a Ni/carbon catalyst

Efficient liquid-phase hydrogenolysis of benzyl phenyl ether using Ni/CB in an EtOH/H2O co-solvent system.

3D QSAR Studies on Benzyl Phenyl Ether Diamidine Derivatives with Antiprotozoal Activities

Human African trypanosomiasis (HAT) is a neglected tropical disease, and some drugs treating HAT have been used for even more than 60 years. Currently, a series of benzyl phenyl ether diamidine derivatives are discovered, which exhibit high antiprotozoal activities and low cytotoxicity, leading to good development prospects. The comparative molecular field analysis (CoMFA) and the comparative molecular similarity indices analysis (CoMSIA) are used to study the relationship between the structure and antiprotozoal activities. The established 3D QSAR model shows not only significant statistical quality, but also satisfies predictive ability: the best CoMFA model had r2 = 0.958 and q2 = 0.766, the best CoMSIA model had r2 = 0.957 and q2 = 0.812, the predictive ability of CoMFA and CoMSIA model were further confirmed by a test set which had 11 compounds, giving the correlation coefficient Qext2 of 0.792, 0.873, respectively. The contour maps and contribution maps show important features that can improve the antiprotozoal activity: position 3 from substituent R4 should be a low electronegativity group, position 4 from substituent R4 should have higher electronegativity, substituent R2 should be selected to a low electronegativity and small bulk group. Together these results may offer some useful theoretical information in designing potential inhibitors.

New antibacterial and 5-lipoxygenase activities of synthetic benzyl phenyl ketones: Biological and docking studies

We investigated twelve benzyl phenyl ketone derivatives which are synthetic precursors of isoflavonoids that are shown be good 5-hLOX inhibitors, especially those that have the catechol group, but these precursors never have been assayed as 5-hLOX inhibitors being a novelty as inhibitors of the enzyme, due to sharing important structural characteristics. Screening assays, half maximal inhibitory concentration (IC50) and kinetic assays of all the studied molecules (5 µg/ml in media assay) showed that 1-(2,4-dihydroxy-3-methylphenyl)-2-(3-chlorophenyl)-ethanone (K205; IC50 = 3.5 µM; Ki = 4.8 µM) and 1-(2,4-dihydroxy-3-methylphenyl)-2-(2-nitrophenyl)-ethanone (K206; IC50 = 2.3 µM; Ki = 0.7 µM) were potent, selective, competitive and nonredox inhibitors of 5-hLOX. Antioxidant behavior was also assayed by DPPH, FRAP, and assessing ROS production, and those with antibacterial and antiproliferative properties relating to 1-(2,4-dihydroxy-3-methylphenyl)-2-(2-chlorophenyl)-ethanone (K208) established it as the most interesting and relevant compound studied, as it showed nearly 100% inhibition of bacterial growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Finally, docking studies were done that helped to characterize how the inhibitor structures correlated to decreased 5-hLOX activity.

Pd(OAc)2-catalyzed synthesis of benzyl phenyl ether derivatives with H2O2 as an oxidant in neat water

A new protocol for Pd(OAc)2-catalyzed reactions of different benzyl bromides and various arylboronic acids has been developed to form functionalized benzyl phenyl ethers. This method represents the first instance where arylboronic acid is used as a reaction substrate for benzyl phenyl ether synthesis with H2O2 as the green oxidant under atmospheric oxygen and pure H2O as an environmental friendly solvent without the requirement for phosphine- and N-based ligands, remarkable functional group tolerance, and considerable yield.

Sulphoxide ligands inbicyclooctanium based ionic liquid: Novel solvent systems for the extraction of f-elements

ABSTRACTThe extraction of Pu4+, PuO22+, Am3+, and Eu3+ by structurally modified sulphoxides in 1-hexyl-1,4-diaza [2.2.2] bicyclooctanium Bis(trifluoromethylsulfonyl)imide was investigated at 25 ± 2 °C in an aqueous acidic medium. The extraction process followed ‘cation exchange’ mechanism. The phenyl substituted ligands showed higher extraction efficiency due to steric and electronic factors and followed the trend: Allyl phenyl sulphoxide (APSO) > Benzyl phenyl sulphoxide (BPSO) > Benzyl methyl sulphoxide (BMSO). The extraction process was thermodynamically spontaneous and only one ligand was found to coordinate in the extracted species for all the metal ions. Oxalic acid was found suitable for Pu4+ stripping. PuO22+, Am3+, and Eu3+ were efficiently back extracted by the Na2CO3 solution. APSO-IL system showed excellent radiolytic stability and all the three solvent systems were found highly selective.

Metabolism of the Strobilurin Fungicide Mandestrobin in Wheat.

The metabolic fate of a new fungicide, mandestrobin, labeled with 14C at the phenoxy or benzyl ring was examined in wheat after a single spray application at 300 g/ha. Mandestrobin penetrated into foliage over time, with both radiolabels showing similar 14C distribution in wheat, and 2.8-3.3% of the total radioactive residue remained on the surface of straw at the final harvest. In foliage, mandestrobin primarily underwent mono-oxidation at the phenoxy ring to produce 4-hydroxy or 2-/5-hydroxymethyl derivatives, followed by their subsequent formation of malonylglucose conjugates. In grain, the cleavage of its benzyl phenyl ether bond was the major metabolic reaction, releasing the corresponding alcohol derivative, while the counterpart 2,5-dimethylphenol was not detected. The constant RS enantiomeric ratio of mandestrobin showed its enantioselective metabolism to be unlikely on/in wheat.

Nickel-Catalyzed Oxidative Coupling Reaction of Phenyl Benzyl Sulfoxides

A novel method to produce disulfoxides diastereoselectively from phenyl benzyl sulfoxides is reported. The Ni(PnBu3)2Cl2]/NIXANTPHOS catalyst system successfully promotes an oxidative coupling reaction of aryl benzylic sulfoxides to disulfoxides. An intermediate aldehyde, produced from the elimination of α-hydroxy sulfoxides, is proposed to generate the key sulfenate anion, enabling the formation of the disulfoxide product. A range of disulfoxides was produced in moderate to high yields (30–83%) and diastereoselectivity (rac/meso ranging from 3:1 to >20:1).

Descriptor selection evaluation of binary gravitational search algorithm in quantitative structure-activity relationship studies of benzyl phenyl ether diamidine's antiprotozoal activity and Chalcone's anticancer potency

In this work, the effect of various gravitational constant functions, G(t), were evaluated on the performance of the newly proposed binary gravitational search algorithm (BGSA) as a feature selection method for chemical systems. To fulfill this aim, linear, exponential, logarithmic and square root functions were studied. These functions were implemented in the binary gravitational search algorithm computer code sequentially and their performances were evaluated in a quantitative structure-activity relationship (QSAR) study for selection of the most informative descriptors. In the QSAR study, sixty cationic benzyl phenyl ether diamidine derivatives, which had been synthesized and evaluated against acute infection of Trypanosoma brucei rhodesiense (T.b. rhodesiense), were examined. The number and the kind of descriptors, which were selected by the BGSA, were highly dependent on the applied G(t) function. The results of internal and external validation tests indicate that the exponential function was superior to the other gravitational constant functions for applying in the binary gravitational search algorithm. A general model was established using seven descriptors for the ten training and validation sets. Regardless of subsetting, the selected descriptors and generated model can successfully describe experimental variation of antiprotozoal activity of benzyl phenyl ether diamidine derivatives. In addition, in another QSAR study, anticancer potency of a series of 87 Chalcone derivatives was satisfactorily modeled by using the BGSA-BRANN method. Comparison of BGSA results with those obtained by genetic algorithm (GA) indicates superiority of the BGSA.

Photodegradation of Strobilurin Fungicide Mandestrobin in Water.

Photodegradation of a new strobilurin fungicide, mandestrobin, was investigated in buffered aqueous solution and synthetic humic water (SHW) under continuous irradiation with artificial sunlight (λ > 290 nm). In both aquatic media, the direct photolysis preferentially proceeded via homolytic bond cleavage at the benzyl phenyl ether, and the subsequent recombination of geminate radicals in a solvent cage gave the photo-Claisen rearrangement products. A radical mechanism in the photochemical rearrangement was strongly supported by a radical-trapping technique using a novel nitroxide spin label combined with electron spin resonance (ESR) and liquid chromatography-mass spectrometry (LC-MS) analyses. Photosensitized generation of hydroxyl radical in SHW might significantly contribute to enhancing the formation of a benzyl alcohol derivative. The series of photolysis products steadily degraded and finally mineralized to carbon dioxide.

Metal-Free C-O Bond Functionalization: Catalytic Intramolecular and Intermolecular Benzylation of Arenes.

A catalytic, metal-free intramolecular rearrangement of benzyl phenyl ethers using nitrosonium salt as a catalyst is described. The optimized reaction conditions enabled a catalytic and metal-free Friedel-Crafts alkylation reaction with benzylic alcohols, producing water as the stoichiometric byproduct. A comprehensive scope (>50 examples) for both approaches and application in drug synthesis were demonstrated. Mechanistic studies suggest a Lewis acid-based mechanism for the metal-free Friedel-Crafts reaction.

Catalytic Transfer Hydrogenolysis of Lignin-Derived Aromatic Ethers Promoted by Bimetallic Pd/Ni Systems

Catalytic transfer hydrogenolysis (CTH) of diphenyl ether (DPE), 2-phenethyl phenyl ether (PPE), and benzyl phenyl ether (BPE)—as model molecules of α-O-4 and β-O-4 as well as 4-O-5 lignin linkages—promoted by bimetallic Pd/Ni systems is reported. Pd/Ni (Pd loading of 3 wt %) catalysts were synthesized by using a simple and economic coprecipitation technique, and its detailed physicochemical characterization was performed by means of H2-TPR, XRD, TEM, and XPS analysis. In the presence of palladium as cometal, an almost complete conversion of DPE was reached after 90 min at a temperature of 240 °C while BPE and PPE C–O bond breaking could be achieved at milder reaction conditions. Pd/Ni bimetallic systems can be magnetically recovered and efficiently used up to eight consecutive recycling tests in the transfer hydrogenolysis of DPE. The investigated substrates were also tested using analogous Ni monometallic systems. Palladium as cometal present in the catalysts was proven to increase the C–O bond cleavage...

Structural elucidation of lignin-carbohydrate complexes (LCCs) from Chinese quince (Chaenomeles sinensis) fruit

The lignin-carbohydrate complexes (LCCs) of the mesocarp (MS) and near the endocarp (NE) of Chinese quince (Chaenomeles sinensis) fruits were analyzed using three different methods of fractioning: milled wood lignin (MWL), LCC extracted from crude MWL with acetic acid (LCC-AcOH), and Bjorkman LCC. The MWL and LCC fractions were characterized by carbohydrate composition analysis, SEC, FT-IR, Py-GC/MS, thermal analysis and 2D HSQC NMR. Notably, large amounts of arabinose and galactose remained in the Björkman LCC fractions suggesting a chemical bond between the lignin and pectin. MWL and LCC-AcOH fractions showed better thermal stability than the Björkman LCC fractions. The structure of MS lignin was similar to that of NE lignin; however, fractions from the different fractionation methods revealed differences. The MWL fractions were rich in benzyl ether and γ-ester linkages, while the Björkman LCC fractions contained phenyl glycoside and γ-ester linkages, and the LCC-AcOH fractions contained phenyl glycoside and benzyl ether linkages. These findings are helpful in understanding the nature of lignin and LCC in Chinese quince fruits and provide a theoretical support for their potential application.