Anions tosyl chloride

A comparison of displacements on (/ )-2-octyl tosylate, chloride and bromide by PhsCLi, Ph3SiLi, PJ GeLi and Pt SnLi is summarized in Table 640. In each case, the Sjv2 product is formed with inversion. The basicity of the triphenylmethyl anion caused... 

Alkyl chlorides, bromides and iodides can be formed by the reaction of alcohols with p-toluenesulfonyl chloride (or tosyl chloride, abbreviated as TsCl) in the presence of a nitrogen base (e.g. triethylamine or pyridine). The OH group is converted into a tosylate (abbreviated as ROTs), which can be displaced on reaction with CF, BF or I-. The stable tosylate anion is an excellent leaving group (SN1 or SN2 mechanism depending on the nature of the alkyl group, R). 

The yV-alkyl-substituted azadiol was treated with an equimolar amount of tosyl chloride and excess alkali metal hydroxide in an aprotic solvent (powdered NaOH, dioxane, room temperature, 3 hr) to give a 60% yield of the monoaza-crown (Kuo et al., 1978). Template effects are important in this cyclization reaction, so sodium hydroxide was used for aza-15-crown-5 and potassium hydroxide for aza-18-crown-6. The intramolecular ring-closure process is the result of the initial formation of a tosylate by the reaction of one alkoxide anion with tosyl chloride followed by displacement of the tosylate leaving group by the second alkoxide anion. The pure monoaza-crowns were isolated from their metal ion complexes by thermolysis under reduced pressure (Kuo et al., 1980). 

Copper and brass (CuZn40) are among the various materials used by Uerdingen et al. in their work [6]. Some imidazolium derivatives with different substituents and varying anions (ethylsulphate, octylsulphate, tosylate, chloride and dimethyl-phosphate) and a pair of quaternary ammonium with methylsulphate or saccharinate as anions were used. In water-free ILs experiments, copper and brass showed to be particularly sensitive to the presence of tosylate anion, with corrosion rates between 15 and 25 mm year at 90 °C whereas ethylsulphate produced corrosion rates in the order of 2 mm year . Addition of a 10 % of water approximately doubles the corrosion rate. 

San Filippo and Silbermann continue their studies on the stereochemistry of the reaction of metallate anions with alkyl halides. MeaSnM (M=Li, Na, K) and 2-octyl tosylate, chloride, and bromide, R X, react as in (59). While complete inversion... 

Now, let s draw out the forward scheme. This multi-step synthesis uses three equivalents of ethylene (labeled A, B, C in the scheme below) and one equivalent of acetic acid (labeled D). Ethylene (A) is converted to 1,2-dibromoethane upon treatment with bromine. Subsequent reaction with excess sodium amide produces an acetylide anion which is then treated with bromoethane [made tfom ethylene (B) and HBr] to produce 1-butyne. Deprotonation with sodium amide, followed by reaction with an epoxide [prepared by epoxidation of ethylene (C)] and water workup, produces a compound with an alkyne group and an alcohol group. Reduction of the alkyne to the cis alkene is accomplished with H2 and Lindlar s catalyst, after which the alcohol is converted to a tosylate with tosyl chloride. Reaction with the conjugate base of acetic acid [produced by treating acetic acid (D) with NaOH] allows for an Sn2 reaction, thus yielding the desired product, Z-hexenyl acetate. 

In the BASF BASIL process that utilizes A-methylimidazole to scavenge HCl byproduct, the acidic ionic liquid A-methylimidazolium chloride [HMIMJCl was formed, with a melting point of 75°C (13,102). Recently, the group of Bronsted acidic ionic liquids with the same cation was extended to include other anions, such as BFF, TfO , and TsO . The melting point of the salt is between 30 and 109°C. Strong hydrogen bonding in the tosylate salt was characterized by IR spectroscopy. 

It has been demonstrated that quatemarization of nitrogen may be realized with alkyl halides or tosylates and iodide is found to be the best anion. Formation of N-unsubstituted pyrrolidines when using an alkyl chloride was tentatively explained by the formation of trimethylsilyl chloride in the reaction medium. This silyl halide participates in the quatemarization of nitrogen to give A-silyl pyrrolidine and finally 1V-H pyrrolidine under the hydrolytic conditions of the work-up. The fact that changing iodide for chloride allows formation of the N-unsubstituted pyrrolidine is a synthetically interesting feature.393... 

When steric hindrance in substrates is increased, and when the leaving anion group in substrates is iodide, SET reaction is much induced (Cl < Br < I). This reason comes from the fact that steric hindrance retards the direct nucleophilic reduction of substrates by a hydride species, and the a energy level of C-I bond in substrates is lower than that of C-Br or C-Cl bond. Therefore, metal hydride reduction of alkyl chlorides, bromides, and tosylates generally proceeds mainly via a polar pathway, i.e. SN2. Since LUMO energy level in aromatic halides is lower than that of aliphatic halides, SET reaction in aromatic halides is induced not only in aromatic iodides but also in aromatic bromides. Eq. 9.2 shows reductive cyclization of o-bromophenyl allyl ether (4) via an sp2 carbon-centered radical with LiAlH4. 

Reaction of the diol with p-toluenesulfonyl chloride in pyridine, however, produced the ditosylate in nearly quantitative yield. SN2 displacements by chloride on neopentyl tosylate, which bears certain structural similarities to the ditosylate precursor of CAMPHOS, have been shown to give good yields of neopentyl chloride. However, when l,2,2-trimethyl-l,3-bis(hydroxymethyl)-cyclopentane ditosylate was allowed to react with sodium chloride in hexa-methylphosphoramide, in an attempt to form the dichloride, only N, A -dimethyl-p-toluenesulfonamide was isolated. Reaction of the ditosylate with lithium chloride in ethoxyethanol was exothermic and HC1 was evolved but the dichloride was not isolated. The isolated product contained at least one oleflnic bond. Similarly, in N, TV-dimethylformamide, lithium chloride and the ditosylate gave a product that decomposed on distillation. Faced with such repeated failures, a dihalide route to CAMPHOS was abandoned in favor of a more direct approach reaction of the ditosylate with diphenylphosphide anion. 

At lower temperatures, a tosylate is formed from the reaction of p-toluenesulfonyl chloride and an alcohol. The new bond is formed between the toluenesulfonyl group and the oxygen of the alcohol. At higher temperatures, the chloride anion can displace the -OTos group, which is an excellent leaving group, to form an organochloride. 

Owing to the fact that HI-6 is at the present time considered as the reactivator of first choice, there are many efforts to improve its application. One approach is the choice of the right counteranion of the reactivator. The anion could influence the solubility and stability of the reactivator in the solution. In 2007,12 different salts of HI-6 (sulfate, chloride, acetate, bromide, phosphate, mesylate, tartarate, iodide, malonate, salicylate, maleinate, tosylate) were prepared and tested to discover how the anion can influence the self-reactivation process. It was found that there is no difference in the reactivation of cyclosarin-inhibited AChE (Kuca et al, 2007b). 

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