Reaction Of Benzyl Bromide Research Articles

Nanoporous Cu doped ZnS nanoparticles an efficient photo catalyst for the chemoselective synthesis of 2-substituted azoles via C-N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence in visible light

ZnS and Cu:ZnS nanoparticles were prepared by aqueous chemical method and characterized by several analytical tools. Nanoparticles have an average size of about ∼ 18 nm and possess highly open mesopores, moderate surface area, and uniform morphology. UV–vis spectra designate that doping of Cu shifted the optical response of the ZnS nanoparticles in to a visible region. These Cu:ZnS nanoparticles were employed as a photocatalyst for chemoselective synthesis of 2-substituted azoles by the reaction of benzyl bromides and 1,2-Diaminobenzene or 2-Mercaptoaniline in visible light. Analogous experiments confirmed that the reaction were proceeds through one pot C–N arylation/ CSp3– H oxidation/ cyclization/dehydration sequence. The enhanced catalytic activity by doping could be attributed to the presence of trapping level generated by copper doping which augments the relaxation time of electron and holes so that they are easily available for the reaction. The method was also applicable for the synthesis of quinazolin-4(3H)-ones.

Ni(II)/Al(0) mediated benzylic $$\hbox {Csp}^{3}$$-$$\hbox {Csp}^{3}$$ coupling in aqueous media

Abstract The reaction of benzyl bromides and chlorides with aluminium metal powder or foil (1.2 eqv.) in the presence of catalytic nickel nitrate (10 mol%) in water at room temperature resulted in homocoupling to the corresponding bibenzyl products which were isolated in moderate to good yields. In sharp contrast, the same reaction in organic solvents like dichloromethane, dimethylformamide, acetonitrile, methanol and toluene yielded only a trace amount of the desired product. The scope of the reaction was tested with substituents on the aromatic ring such as Me-, Cl-, CN-, F-, \(\hbox {NO}_{2}\)-, Ph- as well as \(2{^{\circ }}\) benzyl halides.Graphical abstractThe reagent combination of aluminium metal and catalytic \(\hbox {Ni}(\hbox {NO}_{3})_{2}\) promotes the homocoupling of benzyl bromides and chlorides giving rise to the corresponding bibenzyl products in good to excellent yields. The reaction is greatly facilitated in water and showed good functional group tolerance. Besides the mild reaction condition and bench-friendliness, the present reaction constitutes the first example of aluminium-mediated homocoupling of a halide in water.

Photo‐Decomposable Sub‐Micrometer Albumin Particles Cross‐Linked by ortho‐Nitrobenzyl Derivatives

AbstractStimuli‐responsive particles are widely used as carriers for on‐demand delivery of drugs, genes, proteins, etc., due to their response to environmental stimuli. In this study, photoresponsive albumin sub‐micrometer particles are fabricated by using ortho‐nitrobenzyl derivative 4‐bromomethyl‐3‐nitrobenzoic acid (BNBA) as a cross‐linker. Bovine serum albumin (BSA)‐doped MnCO3 particles are used as the sacrificial template, in which the BSA molecules are cross‐linked by BNBA under the activation of 4‐(4,6‐dimethoxy‐1,3,5‐triazin‐2‐yl)‐4‐methylmorpholinium chloride. After removal of MnCO3 particles by ethylene diamine tetraacetic acid, photoresponsive BSA–BNBA sub‐micrometer particles are obtained. Since the CN bond formed via reaction of benzyl bromide and amine is photocleavable, the particles can be decomposed upon UV irradiation at 365 nm under acidic environment. The loaded macromolecules can be released upon UV irradiation, exhibiting great potential applications of the particles in the field of controlled release.

Specific reactivity of 2,4,6-tri-tert-butylanilide anions and its application to benzylation reagent

The reaction of methyl iodide with an anilide anion prepared from 2,4,6-tri-tert-butylanilide and NaH in CH3CN gave N-methyl anilide (N-alkylation product) as a major product, while in the reaction of benzyl bromide with the anilide anion in DMF, O-benzyl imidate (O-alkylation product) was obtained with almost complete selectivity. The treatment of O-benzyl imidate with alcohols and carboxylic acids in the presence of trifluoromethane sulfonic acid gave benzyl ethers and benzyl esters, respectively.

Photo-responsive polyethyleneimine microcapsules cross-linked by ortho-nitrobenzyl derivatives

Intelligent capsules are widely used as carriers for loading small molecules and particles for their capacity to respond to environmental stimuli. In this study, photo-responsive polyethyleneimine (PEI) microcapsules were fabricated using 4-bromomethyl-3-nitrobenzoic acid (BNBA) bearing a photodegradable ortho-nitrobenzyl group as a cross-linker. PEI-doped CaCO3 particles were used as the sacrificial templates, in which the PEI molecules were cross-linked by BNBA molecules under the activation of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) and N,N-diisopropylethylamine (DIEA). After the removal of CaCO3 particles by hydrochloric acid, the PEI–BNBA capsules were obtained. Since the C–N bond that formed via reaction of benzyl bromide and amine is photo-cleavable, the capsules could be decomposed under UV irradiation at 365nm. The loaded macromolecules could be released upon UV irradiation, exhibiting the microcapsules’ potential applications in the field of controlled release.

ChemInform Abstract: Cobalt‐Catalyzed Intermolecular Stereoselective Bisbenzylation of Alkynes.

AbstractThe cobalt‐catalyzed reaction of benzyl bromides with alkynes in the presence of manganese as reductant produces cis‐1,2‐bisbenzylated alkenes.

Synthesis, QSAR and anticandidal evaluation of 1,2,3-triazoles derived from naturally bioactive scaffolds

In the present study, we used eight natural precursors (1a-h) with most of them having promising antimicrobial activities and synthesised their novel 1,2,3-triazole derivatives (3a-h). In the reaction sequences, the precursor compounds (1a-h) were converted to their respective alkyne (2a-h) followed by addition of benzyl azide freshly prepared by the reaction of benzyl bromide with sodium azide using [3 + 2] azide-alkyne cycloaddition strategy. Structural elucidation of all the triazole derivatives was done using FT-IR, 1H, 13C NMR, mass and elemental analysis techniques. The single crystal X-ray diffraction for 3d was also recorded. The result of in vitro anticandidal activity performed against three different strains of Candida showed that compound 3e was found superior/comparable to fluconazole (FLC) with IC50 values of 0.044 μg/mL against Candida albicans (ATCC 90028), 12.022 μg/mL against Candida glabrata (ATCC 90030), and 3.60 μg/mL against Candida tropicalis (ATCC 750). Moreover, at their IC50 values, compounds 3e and 3h showed <5% hemolysis which indicates the non-toxic behaviour of these inhibitors. Cytotoxicity assay was also performed on VERO cell line and all the derivatives were found non-toxic up to the concentration of 10.0 μg/mL. The in silico technique of 3D-QSAR was applied to establish structure activity relationship of the synthesized compounds. The results reveal the molecular fragments that play an essential role in improving the anticandidal activity.

Kinetics and mechanism of the reaction of benzyl bromide with copper in dimethylacetamide in the presence of oxygen

The reaction of copper metal with benzyl bromide in dimethylacetamide in the presence of oxygen has been studied. Oxidative dissolution of copper follows the single-electron transfer mechanism with formation of benzaldehyde, benzyl alcohols, and copper(II) coordination compounds. The kinetic and thermodynamic parameters of the process have been determined by resistometry. Intermediately formed species have been identified and quantitated, and the reaction stereochemistry has been studied. The reaction mechanism is discussed.

Di-μ-bromido-bis[benzyl(diethyl ether)magnesium

The title benzyl Grignard reagent, [Mg2Br2(C7H7)2(C4H10O)2], was obtained by reaction of benzyl bromide with magnesium in diethyl ether, followed by crystallization from toluene. The asymmetric unit comprises one half-mol­ecule, the structural dimeric unit being generated by inversion symmetry with an Mg⋯Mg distance of 3.469 (2) Å. The Mg(II) atom exhibits a distorted tetrahedral coordination geometry. The crystal packing is defined by van der Waals inter­actions only.

ChemInform Abstract: Switch of Reaction Pathway Induced by Solid Support and Ultrasound.

AbstractThe reaction of benzyl bromide with toluene in the presence of KCN and Lewis acid Al2O3 proceeds via Friedel—Crafts pathway to give a regioisomeric mixture of o‐ and p‐benzyltoluene (III)/(IV).

CuI-Zeolite Catalyzed One-Pot Synthesis of Triazoles from Halides

CuI-USY catalyzed the one-pot, two-step cascade reaction of halides (Cl, Br, I) with sodium azide and alkynes in degassed water under anoxic conditions to give the corresponding triazoles in up to 98% yield (22 examples). In the reaction of benzyl bromide and phenyl acetylene, the catalyst was recovered and reused four times without significant loss of its catalytic activity.

ChemInform Abstract: Effect of Solvents and Effect of Nucleophiles in Nucleophilic Substitution on Benzyl Bromide - A Kinetic Study

The kinetics of the reaction of benzyl bromide with thiourea was studied in different pure (protic and aprotic) solvents and the rate data was correlated using linear multiple regression analysis. From the regression coefficients which describe the susceptibility of rate to different solvent parameters, information regarding the solvent-reagent, and the solvent-intermediate interactions was obtained and solvation models were proposed. Applicability of the Swain-Scott free energy relationship was tested using different sulphur nucleophiles in acetonitrile solvent and the nucleophilicity constant of N-acetylthiourea was computed as 2.74 from the regression line.

Kinetics and mechanism of nickel reaction with benzyl bromide in dimethylformamide

The reaction of nickel with benzyl bromide in DMF has been studied. The reaction intermediates were investigated by different methods and the kinetic and thermodynamic parameters were determined. The reaction of benzyl bromide with nickel was shown to occur on the metal surface by the Langmuir-Hinshelwood scheme, with the formation of benzyl radicals which are recombined and isomerized in solution to form 1,2-diphenylethane and trace amounts of 4.4′-dimethylbiphenyl.

Facile Preparation of Trimethylsulfonium Bromide

Trimethylsulfonium bromide, utilized to make oxiranes and molten salts, has been reported to be prepared from dimethyl sulfoxide and ethyl bromoacetate, alkyl halide and dimethyl sulfide, and dimethyl sulfoxide and bromine. Herein, we report a very simple and convenient method of trimethylsulfonium bromide from a modified Kornblum oxidation condition. Typical Kornblum oxidation is referred to a reaction in which alkyl/aryl halide (tosylate) is reacted with dimethyl sulfoxide followed by a direct workup procedure in basic aqueous solution to prepare corresponding aldehyde (path 1 in Figure 1). However we have found that Kornblum oxidation in the absence of water and base afforded colorless crystalline trimethylsulfonium bromide in about 65% yields after recrystallization. The X-ray crystallographic and NMR data of trimethylsulfonium bromide were consistent with those of the published report. Several pathways can be envisaged for the formation of trimethylsulfonium bromide in our conditions. However we believe that a path 2 in Figure 1 could be a major route in our acidic conditions based on control experiments. We found out that volatile products (methyl bromide, dimethyl sulfide, and hydrogen bromide) were efficiently made in our conditions. That is, we were able to isolate a mixture of aniline hydrobromide and N-methylaniline which was formed in an aniline trap attached at the outlet of reflux condenser. In an another experiment we could observe and collect solid trimethylsulfonium bromide (about 1 gm) formed in a reservoir attached between the reaction flask and reflux condenser, which gave us an information that methyl bromide and dimethyl sulfide were obviously generating in an appreciable amount in our reaction conditions. Supposing a path 2 in Figure 1 to be a major route, then one might ask for the verification of benzyl methanesulfenate. We tried to get any evidence for the existence of benzyl methanesulfenate by both NMR and GC/MS, only to fail. We believe that benzyl methanesulfenate can not survive our acidic conditions. Instead we found out that benzyl methyl sulfide and dibenzyl sulfide were formed. In order to get more pieces of evidence related with this modified Kornblum oxidation reactions, reactions of benzyl bromide with diphenyl sulfoxide and methyl phenyl sulfoxide were carried out. As shown in Figure 2, reactions of benzyl bromide with either diphenyl sulfoxide and methyl phenyl sulfoxide turned out to be very clean by NMR. Trimethylsulfonium bromide was not formed at all in these reactions. Noteworthy was that further oxidation proceeded in reaction of diphenyl sulfoxide to give benzoic acid, instead of benzaldehyde obtained in the reaction of methyl phenyl Figure 1. Reaction of benzyl bromide and dimethyl sulfoxide.

Reaction of Benzyl Bromide with Mn(0) in Dimethylformamide

Reaction of Benzyl Bromide with Mn(0) in Dimethylformamide

A novel rearrangement to 1,2,4-triazolo[1,5-a]quinoxalines.

Reactions of benzyl bromide or benzyl cinnamate with N-(benzotriazol-1-ylmethyl)arylimidoyl chlorides (2a,b) in the presence of t-BuOK occur with opening of the benzotriazole ring affording 1,2,4-triazolo[1,5-a]quinoxalines (3a,b). A possible reaction mechanism is discussed.

Correlation Analysis of the Kinetic Parameters of the Reactions of Benzyl Bromides with Aroylhydrazines in Nitrobenzene

A kinetic study was carried out on the bimolecular reactions of benzyl bromides with aroylhydrazines in nitrobenzene at 40 °C. A correlation analysis showed that the combined effect of structural factors on the reaction rate is additive. The structure of the transition state in these reactions was discussed.

Hydrophilic Aliphatic Polyesters: Design, Synthesis, and Ring-Opening Polymerization of Functional Cyclic Esters

The synthesis and homo- and copolymerization of new cyclic esters containing protected functional groups (hydroxyl, bishydroxyl, amino, and carboxyl) are described. Each of the ε-caprolactone derivatives was generated by the Baeyer−Villiger oxidation of the corresponding cyclohexanone derivative. Monoprotection of 1,4-cyclohexanediol by benzylation or esterification was accomplished in moderate yields by reaction of benzyl bromide or 2,2‘-bis(phenyldioxymethyl)propionyl chloride. Each could be oxidized with pyridinium chlorochromate to yield the respective protected hydroxyl and bis(hydroxyl) functional cyclohexanones. The benzyl ether and benzyl ester protecting groups are readily removed by catalytic hydrogenolysis using Pd/C. Alternatively, ethyl-4-ketocyclohexylcarboxylate was hydrolyzed, and the free carboxylic acid was reesterified to the benzyl or tert-butyl 4-ketocyclohexylcarboxylate by esterification with either benzyl bromide or tert-butyl alcohol. These protecting groups were chosen because they are readily cleaved to the respective carboxylic acids under mild conditions. The aza-cyclohexanone derivative was produced from the commercially available ethylene ketal of 4-piperidone by acetylation with trifluoroacetic anhydride followed by transketalization using p-toluenesulfonic acid in excess acetone. The trifluoroacetyl protecting group is easily removed by NaBH4 reduction. Polymerization of the new monomers was accomplished either in bulk (110 °C) initiated from benzyl 2,2‘-bis(hydroxymethyl)propionate in the presence of stanneous 2-ethyl hexanoate (Sn(Oct)2) or from Al(OiPr)3 in toluene (0 °C), yielding polymers close to their targeted molecular weights (5000−15 000) with modestly narrow polydispersities (1.20−1.35). Removal of the protecting groups on the aliphatic polyesters yielded the functionalized polymers.

Synthesis of [F-18]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC): a PET tracer for tumor delineation

Fluorine-18 labeled 1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC), a new tumor-avid amino acid, was synthesized for positron emission tomography. [18F]FACBC was prepared with high specific activity by nucleophilic displacement with an overall radiochemical yield of 12% (EOB). Synthesis of the triflate precursor was accomplished in nine steps starting from the reaction of benzyl bromide with epichlorohydrin which gave 1-chloro-2-benzyloxy-3-brompropane. A key step involves conversion of 3-benzyloxy-cyclobutane-1,1-dicarboxylate diamide to a mixture of diastereomeric 2-benzyloxycyclobutane hydantoins. Copyright © 1999 John Wiley & Sons, Ltd.

A Novel Synthesis of Benzyl Sulfides and Selenides via Sm/BiCl3 System in Aqueous Media

Benzyl sulfides and selenides are synthesized via reaction of benzyl bromide with disulfides and diselenides promted by Sm/BiCl3 system in aqueous media in moderate to good yields.