Benzyl Chloride Research Articles

Nickel/Photo‐Cocatalyzed Acyl C−H Benzylation of Aldehydes with Benzyl Chlorides

AbstractWe have developed a nickel/TBADT cocatalyzed acyl C−H benzylation of both aliphatic and aromatic aldehydes with primary and secondary benzyl chlorides under mild reaction conditions. The protocol provides a convenient and efficient method to synthesize a variety of ketones.

"VALORIZATION OF RICE STRAW VIA PRODUCTION OF MODIFIED XYLANS AND XYLOOLIGOSACCHARIDES FOR THEIR POTENTIAL APPLICATION IN FOOD INDUSTRY "

The present study attempted to valorise rice straw, one of the most abundant, renewable and economic agricultural wastes, via production of modified xylans and xylooligosaccharides (XOS), which were evaluated for their total antioxidant capacity. The percent contents of extractives, cellulose, hemicelluloses, lignin and ash (silica) in rice straw were found to be 20, 41, 24, 9 and 6, respectively. Hemicellulosic xylan was extracted from straw by reaction with 11% (w/v) sodium hydroxide for about 3 h at 80 °C, so that a yield of about 19.4% was obtained, followed by spectral and thermal analyses. Xylan was then subjected to chemical modifications using acetic anhydride, benzyl chloride and sodium monochloroacetate, and the modifications of functional groups were confirmed by FT-IR and NMR spectral techniques. Controlled acid hydrolysis of xylan was carried out using dilute sulphuric acid (0.1, 0.25, 0.5 and 1.0M) at 121 °C, 15 psi for 10 min to produce XOS-rich hydrolysate. Xylan, modified xylans and XOS exhibited significant concentration dependent AAE values, XOS exhibiting the highest AAE value, followed by xylan, benzylated xylan, carboxymethylated xylan and acetylated xylan. Therefore, rice straw based modified xylans and XOS with potential antioxidant properties may serve as potential candidates for use in food industries as packaging films and functional food ingredients.

Metal-free one-pot oxidative conversion: Molecular Iodine Mediated Oxidation Organic Reactions

Various oxidative compounds such as aldehyde, ketone ester, and acids can be produced in large yields by an effective iodine-mediated oxidative reaction of organic molecules. Molecular iodine is a generally available and commercially extremely inexpensive substance that induces oxidative esterification. With the comparison with different Brønsted acid catalysis, molecular iodine or iodophilic activations proceed the reaction onto a deoxygenation pathway. With only a few mol% of I2, the oxidation occurs very quickly at room temperature. This approach could also be used to transport different benzil derivatives from nonactivated alkynes, such as diaryl acetylenes. Molecular iodine with several mild reagents such as aq. NH3, ∼30% aq. H2O2 and DMSO might be used to convert various one degree alcohols, particularly benzylic alcohols, into the corresponding aromatic amides in suffiently high yields in a one-pot method. Similarly, by treating different benzylic chloride, bromide and iodide with a molecular iodine oxidation medium, the corresponding aromatic amides may be prepared in a one-pot method. The reactions in this section include transformation of several compounds into their respective oxidative products with the metal-free one-pot oxidative.

Emulsion-Templated Porous Polymers for Efficient Dye Removal.

A high internal phase emulsion (HIPE) method was used to produce adsorbents with an interconnected porous structure. HIPE was prepared using vinyl benzyl chloride (VBC), divinylbenzene (DVB), tert-butyl acrylate, and Span80 as the organic phase and water with K2S2O8 and CaCl2 as the water phase. The polymerization of the organic phase produced highly porous polymers called polyHIPE, carrying two functional groups. As a result of the template method, polyHIPEs have a low surface area. To overcome this drawback, polyHIPE was hyper-cross-linked through VBC to create meso- and micropores, resulting in a higher surface area. Then the polymer surface was tailored with carboxylic acid groups by simple hydrolysis of tert-butyl acrylate. The adsorption performances of the acidic functional hyper-cross-linked polyHIPEs prepared for the various reaction times of 0, 15, and 60 min were compared for methylene blue. The hyper-cross-linked polyHIPEs showed an enhanced adsorption kinetics for methylene blue, and the 15 min hyper-cross-linking reaction increased the rate of methylene blue adsorption significantly. It was proven that the polyHIPE adsorbent can be reused by treating it with an aqueous acidic solution in ethanol.

Stereoselective Synthesis of Trisubstituted Alkenes by Nickel-Catalyzed Benzylation and Alkene Isomerization.

Catalytic strategies that provide stereoselective access to highly substituted alkenes from abundant monosubstituted substrates are exceedingly sought-after but rare. Here, we show that a N-heterocyclic carbene-NiI catalytic species mediates efficient union of electronically polarized terminal olefins with benzyl chlorides, in the presence of trimethylsilyl triflate and trimethylamine additives, to generate trisubstituted boron- and arene-containing trans alkenes in excellent regio- and stereoselectivities. Control experiments provide evidence for a mechanism involving branched-selective Heck-type benzylation that overrides substrate control, followed by trans-selective 1,3-hydrogen shift. The method represents a significant addition to the toolbox of reactions for the concise synthesis of unsaturated biologically active compounds.

Stereoselective Synthesis of Trisubstituted Alkenes by Nickel‐Catalyzed Benzylation and Alkene Isomerization

AbstractCatalytic strategies that provide stereoselective access to highly substituted alkenes from abundant monosubstituted substrates are exceedingly sought‐after but rare. Here, we show that a N‐heterocyclic carbene‐NiI catalytic species mediates efficient union of electronically polarized terminal olefins with benzyl chlorides, in the presence of trimethylsilyl triflate and trimethylamine additives, to generate trisubstituted boron‐ and arene‐containing trans alkenes in excellent regio‐ and stereoselectivities. Control experiments provide evidence for a mechanism involving branched‐selective Heck‐type benzylation that overrides substrate control, followed by trans‐selective 1,3‐hydrogen shift. The method represents a significant addition to the toolbox of reactions for the concise synthesis of unsaturated biologically active compounds.

Investigation of Spatial Orientation and Kinetic Energy of Reactive Site Collision between Benzyl Chloride and Piperidine: Novel Insight into the Microwave Nonthermal Effect.

Microwave nonthermal effect in chemical reactions is still an uncertain problem. In this work, we have studied the spatial orientation and kinetic energy of reactive site collision between benzyl chloride and piperidine molecules in substitution reaction under microwave irradiation using the molecular dynamics simulation. Our results showed that microwave polarization can change the spatial orientation of reactive site collision. Collision probability between the Cl atom of the C-Cl group of benzyl chloride and the H atom of the N-H group of piperidine increased by up to 33.5% at an effective spatial solid angle (θ, φ) of (100∼110°, 170∼190°) under microwave irradiation. Also, collision probability between the C atom of the C-Cl group of benzyl chloride and the N atom of the N-H group of piperidine also increased by up to 25.6% at an effective spatial solid angle (θ, φ) of (85∼95°, 170∼190°). Moreover, the kinetic energy of collision under microwave irradiation was also changed, that is, for the collision between the Cl atom of the C-Cl group and the H atom of the N-H group, the fraction of high-energy collision greater than 6.39 × 10-19 J increased by 45.9 times under microwave irradiation, and for the collision between the C atom of the C-Cl group and the N atom of the N-H group, the fraction of high-energy collision greater than 6.39 × 10-19 J also increased by 29.2 times. Through simulation, the reaction rate increased by 34.4∼50.3 times under microwave irradiation, which is close to the experimental increase of 46.3 times. In the end, spatial orientation and kinetic energy of molecular collision changed by microwave polarization are summarized as the microwave postpolarization effect. This effect provides a new insight into the physical mechanism of the microwave nonthermal effect.

Palladium-catalyzed aminocarbonylative cyclization of benzyl chlorides with 2-nitroaryl alkynes to construct indole derivatives

A palladium-catalyzed aminocarbonylative cyclization of benzyl chlorides with 2-nitroaryl alkynes has been developed for the rapid construction of indole skeletons. The reaction utilized nitroarenes as the nitrogen source, Mo(CO)6 as both the CO surrogate and the reductant to furnish various indole derivatives in moderate to high yields.

Investigation of thermodynamic properties of Amine Modified Polystyrene and its use for separation of isomers

In this study, thermodynamic properties, glass transition temperature and isomer separation ability of PVBC (poly (vinyl benzyl chloride)) -Diethanol amine (PVBC-DEA) polymer was investigated by IGC method. For purpose, the retention diagrams were drawn using interactions between PVBC-DEA with selected isomer solvents (i-butyl acetate, n-butyl acetate and t-butyl acetate) at between 85 and 110°C. The glass transition temperature value of the polymer was determined from the retention diagrams as 76°C and the obtained value, it has been understood that this value is compatible with 75.2°C found by differential scanning calorimetry. The selectivity coefficients, ∝, of the isomer solvents were determined for the PVBC-DEA in the infinite dilution, according to the results obtained, it was revealed that the polymer can separate the isomers. The polymer-solvent interaction parameters for Flory-Huggins theory, χ12∞, and the equation of state theory, χ12*,the effective exchange energy parameters, χeff, the weight fraction activity coefficient, Ω1∞, and also the partial molar heat of mixing at infinite dilution of solvent, ΔH¯1∞, the molar heat of vaporization of solvent, ΔH¯v, and the partial molar heat of sorption of solvent, ΔH¯s, were calculated between 85 and 110°C. The obtained results were discussed.

Preparation of Ring-Methoxylated Arylnitromethanes by the Victor Meyer Reaction

AbstractEasily accessible and stable ring-methoxylated benzyl chlorides react with AgNO2 to give mixtures of the corresponding arylnitromethanes and nitrite esters. A modified approach for the isolation of arylnitromethanes is described, which represents a valuable improvement of the established Victor Meyer reaction. The isolation technique, which involves reaction of the nitrite ester with urea in methanol, allows the desired arylnitromethanes to be isolated, without loss, in 29–75% yields, and generates the corresponding recyclable benzyl alcohols. Unexpectedly, ring-methoxylated benzyl iodides cannot be used because they are not sufficiently stable and produce tars under the developed reaction conditions.

“Bitter” Results: Toward Sustainable Synthesis of the Most Bitter Substances, Denatonium Saccharinate and Denatonium Benzoate, Starting from a Popular Anesthetic, Lidocaine

One of the most important aspects associated with the modern production of chemicals is sustainability. To teach students and young scientists to design their research in the spirit of sustainable development, students should be made accustomed to seeking solutions that are not only efficient and cost-effective but also safe and environmentally friendly. However, it is still a great challenge to select appropriate material for a lecture that, in addition to providing educational aspects, will simultaneously attract students’ attention. Therefore, to make learning more accessible and inspiring, it is worth using known molecules with interesting properties, such as denatonium salts, as the main product of the developed sustainable process. In this particular project, lidocaine was alkylated with benzyl chloride in the presence of a catalyst and subsequently subjected to an ion exchange reaction. This path resulted in the formation of two organic salts, denatonium benzoate and denatonium saccharinate, which are considered the most bitter substances currently known to mankind. Additionally, their syntheses were optimized according to green chemistry principles, and subsequently, the structures of the products were identified via spectroscopic methods (FTIR and NMR spectroscopies). Finally, determination of basic physicochemical parameters (solubility in water and octanol–water partition coefficient), according to OECD guidelines, enabled the assessment of the potential impact of these compounds on the natural environment.

Enhance the photocatalytic performance of TiO[formula omitted] nano-semiconductor by simultaneously doping of transition and lanthanide elements for the C[sbnd]C homocoupling reaction under sunlight irradiation

Designing a highly powerful catalytic system for CC bond formation reactions is very challenging in synthetic organic chemistry. Herein, we report twelve new nanoparticles which were synthesized. These nanoparticles included 2-nuclear (transition metal-doped) and 3-nuclear (lanthanide–transition metals) doped titanium oxides with high surface activities and low energy bandgaps. All the obtained nanoparticles were characterized by X-ray diffraction, Brunauer–Emmett–Teller, Langmuir analysis, the Barrett–Joyner–Halenda​ method, field-emission scanning electron microscopy, inductively coupled plasma mass spectrometry, Fourier-transform infrared, diffuse reflection/transmittance spectroscopy and UV–Vis spectroscopy. The roles of the surface activity and energy bandgap of these nanoparticles were tested through a photocatalytic test by considering the synthesis of bibenzyl via dehalogenative CC homocoupling using benzyl chloride as the precursor under sunlight for the first time. Based on the results, upon adding lanthanide as an extra dopant, the surface activity of the nanoparticles was remarkably incremented, while the energy bandgap did not show an observable change after lanthanide doping. According to the results, the efficiency of bibenzyl production was higher in the presence of TixMyLamOz as compared to TixMyOz, with a conversion of 85% for TixCuyLamOz compared to 80% for TixCuyOz, as the most effective catalysts in their categories. Although both types were able to absorb light in the visible and IR regions, the surface activity played a critical role and made TixMyLamOz a more useful photocatalyst in CC homocoupling reactions. Noteworthy, the next step of this experiment is to test these photocatalysts for a series of CC coupled derivatives.

Mesoporous epoxidized soybean oil-supported copper-based magnetic nanocatalyst and amberlite-supported azide as a green and efficient catalytic system for 1,2,3-triazole synthesis.

A new green mesoporous magnetically heterogeneous catalyst was prepared by the copper immobilization onto magnetic epoxidized soybean oil as a nano bio-support and was utilized for the synthesis of 1,4-disubstituted-1,2,3-triazole derivatives in the presence of amberlite supported azide. A great range of triazole derivatives were synthesized from benzyl halides or epoxides halides in high yields at the room temperature. The catalyst was characterized by various techniques such as FT-IR, XRD, VSM, FE-SEM, EDX, TEM, BET, TGA, and ICP analysis. This catalytic system can be reused for five times without any significant decrease in the catalytic activity. Fe3O4@SiO-ESBO/CuO nanocatalyst and amberlite supported azide as a green catalytic system has been used for the regioselective synthesis of triazole derivatives in water. A large range of triazole derivatives were synthesized from benzyl halides or epoxides in high yields.

Graphene oxide enhances thermal stability and microwave absorption/regeneration of a porous polymer

Microwave regeneration of adsorbents offers several advantages over conventional regeneration methods; however, its application for microwave transparent adsorbents such as polymers is challenging. In this study, hypercrosslinked polymer/graphene oxide (GO) nanocomposites with large surface area and enhanced microwave absorption ability were synthesized. Polymers of 4, 4´-bis ((chloromethyl)-1, 1´-biphenyl- benzyl chloride) were hypercrosslinked through the Friedel-Crafts reactions. GO sheets were synthesized through the Hummer’s method. Nanocomposites with different GO contents (1–8 wt%) were synthesized by solution mixing method. Thermogravimetry analysis revealed a large enhancement in the thermal stability of GO-filled nanocomposites compared to pristine polymer. N2 adsorption isotherm analysis showed 7% and 10% reduction in BET surface area and total pore volume of the nanocomposite with 8 wt% GO. Compared to the pristine polymer, the dielectric constant and dielectric loss factor increased from 5 to 17 and 0.05–1.6, respectively, for the nanocomposites with 8 wt% GO. Microwave-assisted desorption of toluene from samples revealed more than 160 ºC and 4 times improvement in the desorption temperature and desorption efficiency, respectively, by addition of 4 wt% GO to the polymer. This study showed the important role of GO addition for efficient microwave-assisted regeneration of polymer adsorbents.

Direct benzylation reactions from benzyl halides enabled by transition-metal-free photocatalysis

An SN2-based photochemical strategy using dithiocarbamate anion as catalyst was developed for the activation of benzyl halides, which are extremely challenging to be applied as radical precursors in visible light photocatalysis. With this transition-metal-free and oxidant-free protocol, the benzylation (or cyanomethylation) of various heterocycles including quinoxalin-2(1H)-ones, coumarin, 2-phenyl-2H-indazole, 1-methyl-5-phenylpyrazin-2(1H)-one, 1-(fluoromethyl)cinnolin-4(1H)-one, and 2,4-dibenzyl-1,2,4-triazine-3,5(2H,4H)‑dione could be realized (46 examples, up to 98% yield). Importantly, some biologically relevant 3-benzylquinoxalin-2(1H)-ones were also be synthesized under mild conditions.

Preparation of asymmetric particles by controlling the phase separation of seeded emulsion polymerization with ethanol/water mixture

Alcohols are discovered for the first time to tune the morphology of poly(vinyl benzyl chloride)-poly(3-methacryloxypropyltrimethoxysilane) (PVBC-PMPS) composite particles through seeded emulsion polymerization within the alcohol/water mixture. Here, monodispersed linear PVBC particles was synthesized through the dispersion polymerization and employed as the seeds. The as-obtained PVBC-PMPS composite particles could be dramatically tuned from core-shell structures to snowman-like particles, to dumbbell-shaped particles, to inverse snowman-like particles when the ethanol content in reaction mixtures is only adjusted within a narrow range. The morphology of fresh PMPS bulges was observed after removing the linear PVBC seeds with N,N’-dimethyl formamide, and their formation mechanism was studied by monitoring the free radical polymerization and sol–gel process of 3-methacryloxypropyltrimethoxysilane. It has been confirmed that the sol–gel kinetics were the main factor on the particles’ morphology. In addition, morphologies of PVBC-PMPS particles were also varied by the MPS feeding amount, types of the co-solvent and pH values of alcohol/water mixtures.

Benzyl chlorides as aldehyde surrogates in the Prins cyclization: Direct access to 2-aryl-4-chlorotetrahydropyrans

An efficient synthesis of 2-aryl-4-chloro-tetrahydropyrans has been accomplished from benzyl chlorides and homoallylic alcohols using FeCl3 as a promoter through a sequential oxidation/Prins cyclization in high yields. This is the first report on the use of benzyl chlorides as surrogates for aldehydes in the Prins cyclization.

Negative-mode ion mobility spectrometry-comparison of ion-molecule reactions and electron capture processes.

The presented work concerns the impact of ionization mechanisms of analytes on detection sensitivity in negative-mode ion mobility spectrometry. The main part of the work is research conducted for selected organic analytes using DT IMS in the negative mode of operation. In the negative mode of detection, two ionization mechanisms can be used: electron capture and ion-molecule reactions. The type of ionization mechanism depends on the carrier gas. The tests were carried out using two carrier gases: air and nitrogen. This allowed for a comparison of the ionization of analytes in the ion-molecule reaction mode with ionization in electron capture mode. Experiments were carried out for tetrachloromethane, trichloromethane, benzyl chloride, 1-chlorobutane, 1-chlorohexane, 1-chloropentane, tetrachlorethylene, 1-bromobutane, 1-bromopentane, 1-bromohexane, hexafluorobenzene, 2-chloroethyl ethyl sulfide (CEES), and methyl salicylate. Most of the tested substances were ionized with the formation of ionized halogen atoms (Br- or Cl-). It was found that among the tested substances, there are those whose effective ionization is possible with the use of both nitrogen and air as carrier gases, those ionized only in electron capture mode or in ion-molecule reaction mode. The important part of the work was an investigation on the effect of oxygen and water admixtures in carrier gases on the detection efficiency of selected organic compounds.

Development of Novel Phosphino‐Oxazoline Ligands and Their Application in Asymmetric Alkynlylation of Benzylic Halides

Comprehensive SummaryA new set of stereochemically diverse phosphino‐oxazoline ligands derived from simple L‐amino acids and 2‐(diphenylphosphaneyl)benzoic acid were developed. Those mono anionic tridentated N,N,P‐ligands promote the Cu‐catalyzed enantioselective radical coupling of terminal alkynes with a broad range of benzylic halides including benzo‐fused cyclic α‐halides and α‐silyl benzyl halides in high yield and excellent enantioselectivity under mild reaction conditions. With multi distinct sites for structural modification, a diverse pool of chiral N,N,P‐ligands is readily accessed, allowing for rapid optimization of the ligand structure for a specific substrate. Notably, the enantioselective alkynlylation of benzylic halides bonds in benzo‐cyclic molecules has also been realized for the first time.

C-Cl Oxidative Addition and C-C Reductive Elimination Reactions in the Context of the Rhodium-Promoted Direct Arylation.

A cycle of stoichiometric elemental reactions defining the direct arylation promoted by a redox-pair Rh(I)–Rh(III) is reported. Starting from the rhodium(I)-aryl complex RhPh{κ3-P,O,P-[xant(PiPr2)2]} (xant(PiPr2)2 = 9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene), the reactions include C–Cl oxidative addition of organic chlorides, halide abstraction from the resulting six-coordinate rhodium(III) derivatives, C–C reductive coupling between the initial aryl ligand and the added organic group, oxidative addition of a C–H bond of a new arene, and deprotonation of the generated hydride-rhodium(III)-aryl species to form a new rhodium(I)-aryl derivative. In this context, the kinetics of the oxidative additions of 2-chloropyridine, chlorobenzene, benzyl chloride, and dichloromethane to RhPh{κ3-P,O,P-[xant(PiPr2)2]} and the C–C reductive eliminations of biphenyl and benzylbenzene from [RhPh2{κ3-P,O,P-[xant(PiPr2)2]}]BF4 and [RhPh(CH2Ph){κ3-P,O,P-[xant(PiPr2)2]}]BF4, respectively, have been studied. The oxidative additions generally involve the cis addition of the C–Cl bond of the organic chloride to the rhodium(I) complex, being kinetically controlled by the C–Cl bond dissociation energy; the weakest C–Cl bond is faster added. The C–C reductive elimination is kinetically governed by the dissociation energy of the formed bond. The C(sp3)–C(sp2) coupling to give benzylbenzene is faster than the C(sp2)–C(sp2) bond formation to afford biphenyl. In spite of that a most demanding orientation requirement is needed for the C(sp3)–C(sp2) coupling than for the C(sp2)–C(sp2) bond formation, the energetic effort for the pregeneration of the C(sp3)–C(sp2) bond is lower. As a result, the weakest C–C bond is formed faster.