O-Toluenesulphonyl chloride

Leucbs and Schulte give m.p. 245-8 vac. dec.) and [a] — 151 /d (N/NaOH). The add forms a N-nitroso derivative, m.p. 243 , which is isomerised by hydrogen chloride in alcohol to a C-nitrosoisostrychninic acid, decomposing at 238-240°. Oesterlin was unable to effect condensation of the acid with o-toluenesulphonyl chloride, but according to Leuchs and Schulte it yields an 0-acetylisostrychninic acid,. 5HgO,... 

The mixture of o- and p-toluenesulphonyl chlorides produced from toluene may be separated by cooling to — 10° to — 20° when most of the p-isomer, which is a solid, m.p. 69°, separates out. Both isomers may be easily converted (e.g., by treatment with solid ammonium carbonate or with concentrated ammonia solution) into the corresponding highly crystalline sulphonamides which may be employed for interesting syntheses. 

By the solvolysis of N-tosyl-O-phenylhydroxylamine, prepared in 75-85% yield from phenoxylamine (Chap. 3) by reaction with 4-toluenesulphonyl chloride in pyridine, 4-fluorophenol resulted regiospecifically in 38% yield accompanied by an imino compound (34%) arising from the reagent which was used at ambient temperature and consisted of a solution of hydrogen fluoride in THF (5 1) (ref. 

Dissolve O 01 g. equivalent of the amino acid in 20 ml. of N sodium hydroxide solution and add a solution of 2 g. of p-toluenesulphonyl chloride in 25 ml. of ether shake the mixture mechanically or stir vigorously for 3-4 hours. Separate the ether layer acidify the aqueous layer to Congo red with dilute hydrochloric acid. The derivative usually crystallises out rapidly or will do so on standing in ice. Filter ofl the crystals and recrystallise from 4—5 ml. of 60 per cent, alcohol. 

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