Toluenesulfonate ester

Nucleophile p Toluenesulfonate ester Product of nucleophilic substitution pi... 

When It IS necessary to prepare secondary alkyl halides with assurance that no trace of rearrangement accompanies their formation the corresponding alcohol is first converted to its p toluenesulfonate ester and this ester is then allowed to react with sodium chloride bromide or iodide as described m Section 8 14... 

The following conversion has been reported in the chemical literature It was earned out in two steps the first of which involved formation of a p toluenesulfonate ester Indicate the reagents for this step and show how you could convert the p toluenesulfonate to the desired product... 

Conversion to p toluenesulfonate es ters (Section 8 14) Alcohols react with p toluenesulfonyl chloride to give p toluenesulfonate esters Sulfo nate esters are reactive substrates for nucleophilic substitution and elimma tion reactions The p toluenesulfo nate group is often abbreviated —OTs... 

Choose the correct enantiomer of 2 butanol that would permit you to prepare (/ ) 2 butanethiol by way of a p toluenesulfonate ester... 

An aiyl methane- or toluenesulfonate ester is stable to reduction with lithium aluminum hydride, to the acidic conditions used for nitration of an aromatic ring (HNO3/HOAC), and to the high temperatures (200-250°) of an Ullman reaction. Aiyl sulfonate esters, formed by reaction of a phenol with a sulfonyl chloride in pyridine or aqueous sodium hydroxide, are cleaved by warming in aqueous sodium hydroxide. ... 

The reaction of alcohols with acyl chlorides is analogous to their reaction with p-toluenesulfonyl chloride described earlier (Section 8.14 and Table 15.2). In those reactions, a p-toluenesulfonate ester was formed by displacement of chloride from the sulfonyl group by the oxygen of the alcohol. Carboxylic esters arise by displacement of chloride from a carbonyl group by the alcohol oxygen. 

Tosylate (Section 11.1) A p-toluenesulfonate ester useful as a leaving group in nucleophilic substitution reactions. 

The second dianhydro-xylitol was obtained23 by methylenation of 1,4-anhydro-DL-xylitol, with paraformaldehyde and concentrated hydrochloric acid, to give the 3,5-methylene acetal this was methylated to the 2-methyl ether, which was hydrolyzed, and the product mono-p-toluenesulfonylated to the 5-p-toluenesulfonic ester. On treatment with aqueous sodium hydroxide at 40-50°, the last gave syrupy l,4 3,5-dianhydro-2-0-methyl-DL-xylitol (17, D form). 

Cesium fluoride, 68 Sulfonic acids and esters p-Toluenesulfonate esters p-Toluenesulfonyl chloride, 313 Trifluoromethanesulfonate esters N-Phenyltrifluoromethanesulfonimide, 142... 

The infrared spectra (benzene solution) of the isohexide nitrates, as well as of their mixed nitric and p-toluenesulfonic esters, are well established. The positions of the v and the bands for the nitrato group are remarkably constant, at 1645 3 cm-1 and 1282 1 -1 (endo), and 1274 1 cm-1... 

Increase in the chain length, symmetrically, increased the reactivity of the secondary tosyloxy group (p-toluenesulfonic ester of dimethyl carbinol, 7.5 of diethyl carbinol, 23 of di-n-propyl carbinol, 24% of NaOTs, after 2 hours at 25°). 

Isobutyl alcohol is then converted to its p-toluenesulfonate ester, which reacts with sodium iodide in acetone in a manner analogous to that of isobutyl bromide. 

The hydroxyl group must be replaced by azide with inversion of configuration. First, however, a leaving group must be introduced, and it must be introduced in such a way that the configuration at the stereogenic center is not altered. The best way to do this is to convert (R)-sec-butyl alcohol to its corresponding p-toluenesulfonate ester. 

Reaction of (R)-2-octanol with p-toluenesulfonyl chloride yields a p-toluenesulfonate ester (tosylate) having the same configuration the stereogenic center is not involved in this step. Reaction... 

Compound A is the p-toluenesulfonate ester (tosylate) of /ran.v-4-/cr/-butylcyciohexanol. The oxygen atom of the alcohol attacks the sulfur of p-toluenesulfonyl chloride, and so the reaction proceeds with retention of configuration. 

As reported in the literature, the alcohol was converted to its corresponding p-toluenesulfonate ester and this substance was then used as the substrate in the nucleophilic substitution step to produce the desired sulfide in 76% yield. 

C.I. Acid Yellow 76, 18850 [6359-88-2] (14), is obtained by coupling diazotized 4-aminophenol onto the pyrazolone component and then esterifying with -toluene-sulfonic acid chloride in an alkaline medium. The toluenesulfonic ester group substantially improves the fastness to milling and makes the shade obtained largely independent of pH the lightfastness is not quite as good as that of C.I. Acid Yellow 17. 

Toluenesulfonate esters (tosylates) can be made from alcohols (with TsCl, pyridine). You have already met tosylates in Chapter 17 because they are good electrophiles for substitution reactions with nonbasic nucleophiles. With strong bases such as f-BuOK, NaOEt, DBU, or DBN they undergo very efficient elimination reactions. Here are two examples. 

If a C3 unit needs to be introduced bearing a carbon chain, then there are several options. A P-amino add could be used as a precursor in a parallel synthesis to those discussed above. Alternatively, a strategy based on malonate syntheses could be employed. Co-condensation of a C-substituted malonate with a primary diamine in boiling ethanol gives reasonable yields of cyclic diamide which may be reduced with borane in THF to yield the desired polyamine (Scheme 1.12 and Protocol 5).18 Another possibility is to prepare a linear bis-toluenesulfonate ester from a malonate by reduction (e.g. LiBH4) and tosylation, followed by a standard toluenesulfonamide cyclisation reaction. Yet another variant, this time giving racemic product, is to react a coumarin derivative with a linear polyamine (Scheme 1.12).1819 In this case, a... 

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