Toluene-sulphonyl chloride

Required Phenol, 0-4 g. 10% sodium hydroxide, 2-5 ml. toluene-/)-sulphonyl chloride, 0-9 g. acetone, 4 ml. 

Required Toluene-/)-sulphonyl chloride, 5 g. ammonium carbonate, 10 g. 

A) Toluene -sulphonates. For directions, using an acetone solution of toluene-/) Sulphonyl chloride, see p. 249 use o 3-o 5 g. of the phenol. Note that the chloride should be dissolved in a minimum of acetone, otherwise separation of the ester may be slow and incomplete. 

Benzene-sulphonylotion. Benzene-sulphonyl chloride, which can be used in place of toluene-/>-sulphonyl chloride, is liquid at room temperature and consequently reacts rapidly when the reaction mixture (as in 3(a)) is vigorously shaken. In general, however, the toluene-/>-sulphonyl derivatives crystallise even more readily than the benzene-sulphonyl analogues, and have lower solubilities and higher m.ps. 

Mix 1 0 g. of the phenol with 2 5 ml. of pyridine, add 2 g. of p-toluene-sulphonyl chloride, and heat on a water bath for 15 minutes. Pour into 25 ml. of cold water and stir until the oil solidifies. Filter, wash with cold dilute hydrochloric acid (to remove pyridine), with cold dilute sodium hydroxide solution (to remove any phenol present), and then with cold water. Recrystallise from methyl or ethyl alcohol. 

Methyl p-toluenesulphonate. This, and other alkyl esters, may be prepared in a somewhat similar manner to the n-butyl ester with good results. Use 500 g. (632 ml.) of methyl alcohol contained in a 1 litre three-necked or bolt-head flask. Add 500 g. of powdered pure p-toluene-sulphonyl chloride with mechanical stirring. Add from a separatory funnel 420 g. of 25 per cent, sodium hydroxide solution drop by drop maintain the temperature of the mixture at 23-27°. When all the alkali has been introduced, test the mixture with litmus if it is not alkaline, add more alkali until the mixture is neutral. Allow to stand for several hours the lower layer is the eater and the upper one consists of alcohol. Separate the ester, wash it with water, then with 4 per cent, sodium carbonate solution and finally with water. Dry over a little anhydrous magnesium sulphate, and distil under reduced pressure. Collect the methyl p-toluenesulphonate at 161°/10 mm. this solidifies on cooling and melts at 28°. The yield is 440 g. 

The next and only other major kinetic study was carried out by Jensen and Brown184, who used aluminium chloride as catalyst, nitrobenzene as solvent, benzene- and p-toluene-sulphonyl chlorides as sulphonylating agents and benzene, chlorobenzene, alkyl- and polyalkylbenzenes as aromatic substrates184. 

This type of reaction was originally carried out with ethyl iodide1 and has been extended to other alkyl halides,2 halogeno-carboxylic esters3 and to substituted arsine halides.4 Incidentally when p-toluene sulphonyl chloride and naphthalene-2-sulphonyl chloride were allowed to react with sodium diethyl phosphite, the corresponding disulphones were obtained in small yield.5... 

In other words ortho- and para-toluene sulphonyl chlorides are formed, which on high temperature hydrolysis produces ortho- and para-toluene sulfonic acids. This mixture on neutralization, caustic fusion, and acidification produces a mixture of ortho- and para-cresols. The resultant product contains approximately 85% p-cresol and 15% o-cresol from which pure para-cresol (99%- -) and pure ortho-cresol (99%-h) can easily be obtained. 

Prepare a solution of sodium hydroxide (40 g, 1 mol) in distilled water (200 mL) and cool to room temperature. Place the solution in a 2L two-necked round-bottomed flask fitted with a thermometer and add a solution of tetraethylene glycol (68 g, 60 mL, 0.35 mol) in THF (200 mL) while stirring. Put the flask in an ice bath and cool to 0 °C. Place a solution of p-toluenesulphonyl chloride (145 g, 0.76 mol) in THF (200 mL) in a pressure-equalized addition funnel and add dropwise to the stirred glycol solution over 3 h or so. Carefully monitor the temperature of the solution and keep below 5 °C throughout. Once the addition of the p-toluene-sulphonyl chloride solution is complete, continue to stir the solution for a further 1 h at below 5 °C. Pour onto a mixture of ice and water (250 g/250 mL) and continue to stir. When all the ice has melted, remove most of the THF by rotary evaporation and extract the product into dichloromethane (3 x 100 mL). Dry the dichloromethane extract over calcium chloride, filter and remove the solvent by rotary evaporation. The product, tetraethylene glycol ditosylate (3), is obtained as a colourless oil. 

Saccharine is made on a large scale so there is plenty of toluene-/ -sulphonyl chloride spare and it is cheap. This is one reason why the tosyl group is such a popular leaving group with organic chemists (see Chapter 4). 

Step-1. The cis-5-hydroxy-2-propyl cyclopentane on being treated with p-tosyl chloride ii.e., p-toluene sulphonyl chloride) in the presence of dry pyridine yields the corresponding cis-tosyl derivative. 

The interaction between 3 moles of nicotinic acid and 1 mole of 2-hexyl-2-(hydro-xymethyl)-1,3-propanediol in the presence of pyridine as a medium and para-toluene sulphonyl chloride as a catalyst gives rise to the formation of 1 mole of the desired ester, hepornicate and 3 moles of water are eliminated. 

It is very important to note that the solution of 2-hexyl-2-(hydroxymethyl)-1,3-propanediol in pyridine must be added to the solution of nicotinic acid, p-toluene sulphonyl chloride in pyridine almost dropwise with frequent stirring (below 80°C). 

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