Methyl toluene-/>-sulphonate

Some less reactive tertiary amines can be mixed with an excess of methyl toluene-/)-sulphonate, m.p. 28 , and the mixture (without a solvent) heated to a much higher temperature. The mixture is allowed to cool, but before solidification occurs, it is thoroughly stirred with ether to extract unused sulphonate, and the insoluble quaternary metho-toluene-/)-sulphonate may then crystallise. If ciystallisation does not occur, dissolve this residue in ethanol and treat one portion with ethanolic picric acid (to precipitate the methopicrate) and another portion with cold concentrated ethanolic sodium iodide (to precipitate the methiodide). (M.ps. of the siilphon.ates, pp. 553 -554.)... 

Amine BJ. H.P. Methlodide PIcrate Methyl /)-toluene- sulphonate Other Derivatives... 

Picrate Methyl toluene- sulphonate Other DerlTatives... 

Dissolve 2-3 g of methyl toluene-p-sulphonate in 10 ml of dry toluene, add 1 g of the amine and boil the mixture for 20-30 minutes. Cool, and filter the precipitated quaternary salt. Recrystallise by dissolving the solid in the minimum volume of boling ethanol and then adding ethyl acetate until crystallisation commences. Filter the cold mixture, dry rapidly on a porous plate and determine the m.p. immediately. 

The benzyltrialkylammonium salts (R3N,CH2,Ph Cle) are prepared similarly 3 g of redistilled benzyl chloride replaces the methyl toluene-p-sulphonate. 

Methyl toluene-p-sulphonate combines with many tertiary amines to yield crystalline derivatives ... 

Enamines derived from aldehydes react with SchifFs bases in methanol in the presence of toluene-/ -sulphonic acid to yield tetrahydroquinolines thus l-morpholino-2-methyl-propene and benzylideneaniline afford 3,3-dimethyl-4-morpholino-2-phenyl-l,2,3,4-te-trahydroquinoline 238 (equation 100)123. 

A further route to compounds with an aromatic ring A lies in an unusual acid-catalysed rearrangement of steroidal A -3-ketones. Testosterone (35) is reported to give the 4-methyl aromatic compound (36) with trichloroacetic anhydride in the presence of toluene- -sulphonic acid [178]. The mechanism of this reaction is not clear. 

A group of reactions involving 16,17-epoxy-pregnane derivatives illustrates the facility of C(is) methyl migration to an electron deficient C(i ). The i6a,i7a-epoxypregnan-20-ones (13) react with acetic anhydride and toluene- -sulphonic acid [24], hydrogen fluoride [23], and other acidic reagents [23,26], to form i7a-acetyl-i7/5f-methyl-i8-nor-olefins (14) and (15). The preferred position of the double bond apparently... 

Methylation of the dyestuff.— I he foregoing product is boiled with 200 grams of anhydrous sodium carbonate and 200 grams of methyl toluene-p-sulphonate in 2000 c.c. of spirit, the alkylation being complete when a test portion on dilution with water remains red, the process taking about eight hours. The alcohol is then distilled off and the residue dissolved in 5000 c.c. of hot water, filtered, and the dye precipitated by the addition of hydrochloric acid. The mixture is boiled, filtered, and washed with hot water. 

Sulphonic Acids of Benzene Homologues.—The homologues of benzene react in the same way toward sulphuric acid with the difference, already mentioned, that substitution takes place even more easily, due to the presence in the ring of methyl or other aliphatic radicals. Toluene sulphonic acids are, therefore, more easily prepared than benzene sulphonic acid. 

Toluene Sulphonic Acids, para and ortho.—With the methyl group already substituted in the benzene ring the sulphonic acid group enters the para and ortho positions in preference to the meta. If one sulphonic acid group is substituted a second one enters the position meta to the first. These facts are of importance in connection with syntheses to be considered later, e.g. in the preparation of saccharin (p. 712). 

Poly(2-alkyl oxazoline)s having methacrylate or acrylate end groups were prepared by two methods [182]. a) Living polyoxazoline chains, prepared using methyl p-toluene sulphonate as initiator, were end-capped by reaction with metal salts or tetraalkylammonium salts of acrylic or methacrylic acid or a trialky-lammonium salt or trimethylsilyl ester of methacrylic acid (functional termination). b) The living polymers were terminated with water in the presence of Na2C03 to provide hydroxyl-terminated chains. Subsequent acylation with acry-loyl or methacryloyl chloride in the presence of triethylamine led to the formation of the macromonomers. The procedures are outlined in the following Scheme 51. 

Virtually all of the methods for determining acyl groups developed up to now are based on re-esterification of the initial compound with sulphuric acid, a mixture of methanol with hydrochloric or p-toluenesulphonic acid, or with a mixture of p-toluene-sulphonic acid and its methyl ester [165—170]. The esters formed in the reaction were determined by analysing an aliquot of the reaction solution or by blowing-off the reactor with a carrier gas. Alkaline hydrolysis with subsequent determination of acetic acid has also been used for identifying acyl groups [167]. 

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