Presence Of Benzyl Chloride Research Articles

Single Pot Benzylation of O-Xylene with Benzyl Chloride and Benzyl Alcohol Over Pillared Montmorillonites

Abstract Improvement of product selectivity is a major concern of the day. Presence of a coreactant can alter the rate as well as product selectivity of many key reactions like Friedel-Crafts benzylation. Single pot benzylation of o-xylene with benzyl chloride and benzyl alcohol was studied over transition metal exchanged pillared clay catalysts. Complete conversion of benzyl alcohol occured within one hour with 100% monoalkylated product selectivity. The reaction of o-xylene with benzyl alcohol was found to proceed fast in presence of benzyl chloride in single pot, than when present alone as the benzylating species. This enhancement occurs at the expense of no reaction of benzyl chloride, which when present alone reacts faster than benzyl alcohol. Existence of a second transition metal exchanged between the pillars increased the rate of the reaction. A detailed investigation of the reaction variables suggested preferential adsorption of benzyl alcohol to catalyst active sites as the reason.

Iron(II) complexes bearing anilido-imine ligands: Synthesis and catalysis on ATRP of methyl methacrylate

Reactions of the ortho-C6H4(NHAr)-(CHNAr) with nBuLi and subsequent addition of FeCl2 afford the anilido-aldimine Fe(II) complexes [(ArNCHC6H4-NAr)Fe]2(μ-Cl)2 (Ar=2,6-Me2C6H3 (1a); Ar=2,6-Et2C6H3 (1b)), and (ArNCHC6H4-NAr)Fe(μ-Cl)2Li(THF)2 (Ar=2,6-iPr2C6H3 (1c)). Similarly, reactions of the 2-(ArNC(H))C6H4-HNC9H6N with nBuLi and FeCl2 give the N,N,N-tridentate iron complexes {[2-(ArNC(H))C6H4-NC9H6N]Fe}2(μ-Cl)2 (Ar=2,6-Me2C6H3 (2a), 2,6-Et2C6H3 (2b), and 2,6-iPr2C6H3 (2c)). The X-ray diffraction analysis reveals that 1a and 1b are dimeric complexes and 1c is hetero-binuclear complex. Fe(II) atoms in these complexes are all in a distorted tetrahedral geometry. Complex 2c was confirmed to be a dimeric complex with the iron atom in a trigonal bipyramidal geometry. Complexes 1a–1c show moderate activities in ATRP of MMA in the presence of benzyl chloride (BnCl). While complexes 2a–2c are inert under the same condition.

Nickel(II) Complexes Containing Bidentate Diarylamido Phosphine Ligands

A series of diamagnetic divalent nickel complexes supported by bidentate diarylamido phosphine ligands have been prepared and characterized. Deprotonation of N-(2-diphenylphosphinophenyl)-2,6-diisopropylaniline (H[iPr-NP]) and N-(2-diphenylphosphinophenyl)-2,6-dimethylaniline (H[Me-NP]) with n-BuLi in THF at −35 °C produced the corresponding lithium complexes, [iPr-NP]Li(THF)2 and [Me-NP]Li(THF)2, respectively. The chloride complex {[iPr-NP]NiCl}2 is accessible from the reaction of NiCl2(DME) with [iPr-NP]Li(THF)2 or H[iPr-NP] in the presence of triethylamine. Addition of PMe3 to {[iPr-NP]NiCl}2 afforded [iPr-NP]NiCl(PMe3), from which [iPr-NP]NiMe(PMe3), [iPr-NP]NiPh(PMe3), and [iPr-NP]Ni(η3-CH2Ph) were prepared from the metathetical reactions with appropriate Grignard reagents. Solution NMR data of [iPr-NP]NiMe(PMe3) revealed two geometric isomers at room temperature with the major species carrying PMe3 cis to the phosphorus donor of the amido phosphine ligand. Interestingly, only one of the possible isomers is observed for [iPr-NP]NiCl(PMe3) and [iPr-NP]NiPh(PMe3), in which the two phosphorus donors in the former are exclusively cis whereas those in the latter are trans. The benzyl complexes [iPr-NP]Ni(η3-CH2Ph) and [Me-NP]Ni(η3-CH2Ph) are prepared directly from the reactions of [iPr-NP]Li(THF)2 and [Me-NP]Li(THF)2, respectively, with Ni(COD)2 in the presence of benzyl chloride. The η3-feature of the benzyl ligand maintained in solution is elucidated by the 1JCH value observed for the benzylic methylene group in the NMR spectroscopy. In addition to the spectroscopic data for all new molecules, X-ray structures of H[iPr-NP], [Me-NP]Li(THF)2, [iPr-NP]NiCl(PMe3), [iPr-NP]NiMe(PMe3), [iPr-NP]NiPh(PMe3), [iPr-NP]Ni(η3-CH2Ph), and [Me-NP]Ni(η3-CH2Ph) are presented.

Efficient methoxycarbonylation of benzyl chloride without external carbon monoxide: a further application of methyl formate in synthesis using PdCl 2(PPh 3) 2 as catalyst

The decarbonylation reaction of methyl formate induced by Mg(OMe) 2, in the presence of benzyl chloride and dichlorobis(triphenylphosphine)palladium gives rise selectively to methyl phenylethanoate with turnover numbers and turnover frequencies up to ca. 2400 and 1000 h −1, respectively.

Electrochemical reductive alkylation of (benzophenone)Cr(CO) 3 and (benzophenone)[Cr(CO) 3] 2

The electrochemical reduction of (benzophenone)Cr(CO) 3 and (benzophenone)[Cr(CO) 3] 2 in hthe presence of a series of alkyl chlorides which are more difficult to reduce, has been carried out in N,N-dimethylformamide on a mercury pool cathode. When methyl chloride and p-cyanobenzyl chloride are used as alkylating agents, complexed monoalkylated ethers are exclusively obtained as substitution products, in yields ranging from 36 to 54%. Complexed alkylated alcohols aer isolated as the major products when (benzophenone)Cr(CO) 3 is reduced in the presence of benzyl-chloride and its 2,3,5-trimethyl derivative, in 48 and 44% yields, respectively. These last results suggest the intermediate formation of a charge transfer complex between the aromatic ring of the electrophile and the complexed ketone.

Stereoselective electrochemical synthesis and cathodic behaviour of (9- exo-benzyl-η 6-fluorene)chromium tricarbonyl

The one-electron electrochemical reductive cleavage of (η 6-fluorene)Cr(CO) 3 gives the (η 6-fluorenyl)Cr(CO) 3anion. This anion reacts at 0 °C in DMF with benzyl chloride present in excess during electrolysis to give (9- exo-benzylfluorene)Cr(CO) 3 stereoselectively in 64% yield. At higher temperatures there is competing formation of the exo and endo isomers. The reaction of Cr(CO) 6 with 9-benzylfluorene is neither stereoselective nor regioselective, and gives moderate yields of the exo and endo isomers (26 and 17%, respectively). The one-electron reduction of the exo isomer generates the conjugated base which initiates the exo-endo transformation. In the presence of benzyl chloride, the base-catalyzed isomerization competes with a slow benzylation of the base, and (9,9′-dibenzylfluorene)Cr(CO) 3 can be isolated.

Reaction of N-p-tolylsulphonylsulphimides with halide ion in dimethylformamide

The halide ion catalysed rearrangement of N-p-tolylsulphonylsulphimides [Ar–S(Ts)–R; R = Me or PhCH2] was found to afford nearly quantitatively the corresponding sulphenamide [ArSN(Ts)R] and is considered to proceed through a Stevens-type intramolecular rearrangement. The kinetic study revealed that the rate of the reaction of S-aryl-S-methyl-N-p-tolylsulphonylsulphimides with lithium chloride in dimethylformamide obeys a second-order kinetic equation v=k2[Sulphimide][LiCl]. However, the lithium chloride concentration remained constant throughout the reaction, i.e. v=kapp[Sulphimide]. This suggests that the reaction is catalysed by chloride ion. Furthermore, with only a 1/10 molar amount of lithium chloride the sulphimide afforded the rearranged product quantitatively. The activation parameters for the reaction are ΔH‡ 26·7 kcal mol–1 and ΔS‡–4·1 cal mol–1 K–1 respectively, and a Hammett ρ value of +1·7 was obtained. When the reaction of S-methyl-S-phenyl-N-p-tolylsulphonylsulphimide with LiCl was carried out in the presence of benzyl chloride, the only rearranged product obtained was N-benzyltoluene-p-sulphonamide. Methyl chloride formed in this reaction was trapped as methyl p-tolyl sulphide upon addition of toluene-p-thiolate. These observations suggest that the catalytic rearrangement proceeds through initial formation of alkyl halide and subsequent alkylation of sulphenamide anion involving a rate-determining nucleophilic attack of halide ion on the α-carbon atom attached to the trivalent sulphur atom of the sulphimide.

Detection of benzyl and benzal derivatives

A sensitive spot test is described for the detection of benzyl cyanide on the basis of Zimmermann reaction. With aid of this test benzyl cyanide can be detected in the presence of benzyl chloride. Another spot test of benzyl cyanide is based on the nitration of this compound yielded p-nitrobenzyl cyanide, which is an acidbase indicator. When warmed with potassium cyanide, benzyl chloride forms benzyl cyanide, which can be detected by Zimmermann reaction. The reaction may be employed for selective tests, e.g., for the detection of benzyl chloride in the presence of chlorobenzene or benzal chloride. If benzyl chloride is nitrated the product yielded gives the Zimmermann reaction, this is different from benzal chloride. A new test for benzal chloride is worked out based on the reaction with phenylhydrazine and potassium bromate. By means of this test benzal chloride can be detected in the presence of benzyl chloride.

The Photolysis of Aqueous Solutions of Cystine in the Presence of Benzyl Chloride

The Photolysis of Aqueous Solutions of Cystine in the Presence of Benzyl Chloride