Sodium toluene-p-sulphonate

Experiment 6.37 SODIUM TOLUENE-p-SULPHONATE AND TOLUENE-p-SULPHONIC ACID... 

Superhydride has also been used for the hydrogenolysis of alkyl toluene-p-sulphonates, and an illustrative example is given in Expt 5.4 for the preparation of cyclooctane from cyclooctyl toluene-p-sulphonate. A sodium borohydride hydrogenolysis of alkyl halides and of alkyl methane- and toluene-p-sulphonates under PTC conditions provides an interesting variant of this reaction.9... 

The sulphonation of toluene (Expt 6.37) with concentrated sulphuric acid at 100-120°C results in the formation of toluene-p-sulphonic acid as the chief product, accompanied by small amounts of the ortho and meta isomers these are easily removed by crystallisation of the sodium salt of the para isomer in the presence of sodium chloride. Sulphonation of naphthalene at about 160°C yields largely the 2-sulphonic acid (the product of thermodynamic control) (Expt 6.38) at lower temperatures (0-60 °C) the 1-sulphonic acid (the product of kinetic control) is produced almost exclusively. In both cases the product is isolated as its sodium salt. In anthraquinone the carbonyl groups deactivate the aromatic nucleus towards electrophilic attack and vigorous conditions of sulphonation are required, i.e. oleum at about 160 °C. The product is largely sodium anthraquinone-2-sulphonate (Expt 6.39). 

The free sulphonic acids [e.g. toluene-p-sulphonic acid, for preparation see, Expt 6.37, Note (1)], as opposed to their sodium salts, may sometimes be obtained directly if the sulphonation reaction is carried out with continuous removal of the water formed in the reaction, conveniently by using a Dean and Stark water separator. p-Xylene-2-sulphonic acid (Expt 6.40) is an example of a sulphonic acid whose solubility in water is such that it crystallises directly from the reaction medium and hence it may readily be isolated. 

Deprotection of allyl aryl ethers is accomplished by protonolysis with palladium on activated charcoal in methanol solution in the presence of toluene-p-sulphonic acid,42 or by reduction with sodium bis(2-methoxy-ethoxy)aluminium hydride in toluene solution43 (Aldrich). This latter reagent also cleaves aryl benzyl ethers. 

Details are now available of the reactions of peracids and of hydrogen peroxide with the imines (10) and (11). The reactions of the product oxaziridines and nitrones with the same two oxidants were also discussed. The reactions of sodium borohydride, benzoyl chloride, and toluene-p-sulphonic acid with the hydroxy-nitrones (12) and (13) have been reported.12 The c.d. spectra of 2-substituted pyrrolidines have been compared with that of conanine (14).13... 

Tosylhydrazones (260) of 3-oxo-steroids (and presumably of other suitable carbonyl derivatives) are reduced to saturated hydrocarbons (261) by sodium cyanoborohydride and toluene-p-sulphonic acid in dimethylformamide-sulpho-... 

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. 

The ylide from methoxymethyltriphenylphosphonium chloride reacts with the ketone (102) to give (103). Treatment of (103) with trifluoroacetic acid or toluene-p-sulphonic acid gave the cyclized product (104). Sodium-ammonia reduction of this was completely stereoselective, leading to the 9aH-compound (105) the homo-B-ring adopts a chair conformation. ... 

CarbocycUc Steroids.— The Torgov synthesis continues to exhibit its great versatility and was recently employed in the first synthesis of B-homo-oestrone. Condensation of the vinyl alcohol (407) and 2-methy 1-cyclopentane-l,3-dione in the presence of l,4-diazabicyclo[2,2 ]octane and cyclisation with toluene-p-sulphonic acid gave the B-homo-oestrapentaene (409) in 33 % overall yield from 3-methoxybenzosuberone. A three-stage reduction by sodium borohydride, catalytic hydrogenation, and lithium-ammonia afforded 3-methoxy-B-homo-... 

Treatment of (31) with crotyl chloride-potassium carbonate in DMF afforded (33), which was converted into (34) by heating in a sealed tube. Methylation of the phenol (34) with methyl iodide-potassium carbonate gave (35). Osmic acid-sodium periodate oxidation produced the keto-aldehyde (36). Acetalization by standard methods gave the diacetal (37). Reduction of (37) with lithium in liquid ammonia and subsequent toluene-p-sulphonic acid work-up afforded (38) in a yield of 50 %. A vinylogous aldol condensation was effected with methan-olic potassium hydroxide. The resulting mixture was oxidized with chromium... 

The Eco2 reaction of 9-fluorenyl toluene-p-sulphonate with sodium hydroxide in 90% methanolic acetone has a primary kinetic hydrogen isotope effect of only 2.3 at 25°C . It is difficult to compare this result with that for the corresponding nitrate but if a transition state with considerable carbanion character is involved, then the indications are that nitrite is a better leaving group than toluene-p-sulphinate. It would be worth while to investigate the sulphur isotope effect for this latter reaction. 

Equation (a) Toluene-pam-sulphonamide on dissolution in an excess of sodium hypochlorite solution gives rise to the formation of toluene-p-sulphon-chloro-sodio-amide (I), which being water-soluble does not ordinarily crystallise out unless and until very concentrated solutions are employed. 

Details of an alternative synthesis of 13-methyl-protoberberines have been published. The starting point is an N-phenethyl-homophthalimide of the type (83), and monomethylation is achieved by its Michael addition to methyl vinyl ketone to give the ketone (84 R = H), followed by methylation of this to the intermediate (84 R = M). Conversion of this into the ethylene ketal, followed by reduction with sodium borohydride and heating with toluene-p-sulphonic acid, results in the unsaturated lactam (85), and cyclization of this compound yields the lactam (86), which can be reduced to the 13-methyl-tetrahydroberberine. ... 

A review of the preparation, structures, and stereochemistry of cyclic acetals of the aldoses and aldosides has appeared. Pyridinium toluene-p-sulphonate has been reported to be a mild catalyst for the formation and cleavage of dioxolane-type acetals, although no carbohydrate examples were quoted. Acetals and ketals of carbohydrates have been used as co-agents to introduce chirality into the products of sodium borohydride reduction of acetophenone, propiophenone, etc ... 

Phase-transfer catalysis has been used to prepare toluene-p-sulphonates. When sulphonation at the anomeric position of 2,3.5,6-di-O-cyclohexylidene-D-manno-pyranose was attempted using toluene-p-sulphonyl chloride-benzene-butyl-triethylammonium chloride, the a-mannosyl chloride and the a,a-iinked manno-disaccharide were obtained in addition to the desired product. Selective sulphonation of benzyl (or methyl) 4-0-benzyl-0 -L-rhamnopyranoside with toluene-p-sulphonyl chloride-aqueous sodium hydroxide-dichloromethane gave 65% 2-O-toluene-p-sulphonate. ... 

The unsaturated nucleoside (53) has been prepared in good yield by electrochemical elimination from either the 2 -bromo-arabino- or the 3-bromo-xylo-nucleoside indicated in Scheme 14 however, the electrolyte can control the product obtained, for whereas 2-bromo-2 -deoxy-3, 5-di-O-propanoyl-uracil gave the 2, 3-unsaturated nucleoside in presence of tetraethylammonium toluene-p-sulphonate in methanol, with sodium acetate a mixture of products was obtained 3-deoxy-3-iodo-adenosine yielded 3-deoxy-adenosine (cordycepin) besides the 2, 3-unsaturated nucleoside.1-Acetyl-glycenose derivatives have been condensed with purine and pyrimidine derivatives in presence of antimony... 

Thiazolo[3,2-a]quinazolines.—[C3NS-C4N2-C6]. A number of thiazolo-[3,2-a]quinazolones have been obtained by the application of conventional cyclization reactions. Thus, the condensation of 2-mercapto-3-phenylquinazolin-4(3/f)-one (301) and phenacyl bromide yields the S -alkylated derivatives (302) which are reduced by sodium borohydride tol,2-dihydro-2-(a-hydroxyphenethyl)mercapto-3-phenylquinazolin-4(3/f)-one (303). Cyclodehydration by acetic anhydride or toluene-p-sulphonic... 

Improved yields of methyl 2,3,4-tri-0-acetyl-6-deoxy-6-iodo-a-D-glucopyrano-side have been recorded in a synthesis that involved heating the corresponding 6-toluene-p-sulphonate with sodium iodide in butanone. Moffatt s group... 

Several double-headed nucleosides have been reported by Russian workers. Thus, treatment of 2, 3 -0-isopropylideneuridine 5 -toluene-p-sulphonate with the sodium salt of 6-methylthiopurine gave the purine-pyrimidine nucleoside (370) after removal of the protecting group a related double-headed nucleoside... 

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