Pyridines toluenesulphonyl chloride

Esters of /i-toluenesulphonic acid, which are of great value as alkylating agents, may be prepared by interaction of p-toluenesulphonyl chloride and the alcdiol in the presence of sodium hydroxide solution or of pyridine, for example ... 

This is formally the reverse of the BA1,1 cleavage of an ester, and is the only one-stage mechanism for ester formation available for the ionized carboxyl group. Numerous methods are, of course, available which involve initial electrophilic attack on the carboxylate group, followed by a displacement at the carbonyl carbon atom of the intermediate formed, which is often an anhydride. An example134 is the esterification of carboxylic acids in the presence ofp-toluenesulphonyl chloride in pyridine, viz-... 

Borane-methyl sulfide complex (68 ml, 0.71 mol) was added dropwise to a solution of (S)-(+)-mandelic acid (98.5 g, 0.65 mol) in THF (900 ml) at room temperature (RT) under a flow of argon over 3 h. The reaction was stirred for 6 h. Then methanol was added dropwise and stirring continued for a further 13 h. The volatiles were then removed in vacuum, the residue stirred in methanol, and the process repeated 3 times. Column chromatography (MeOH-ethyl acetate-petrol, gradient elution) of the residue afforded the diol (57.3 g, 64%). p-Toluenesulphonyl chloride (80 g, 98% 0.41 mol) was then added portionwise to a solution of the diol in pyridine (700 ml) at 0°C over 8 h. The reaction was stirred at RT for 13 h, then the volatiles removed in vacuum. 

Rearrangements related to the C3 - C4 ring expansion of oxaspiropentanes occur on treating methylenecyclopropane (69) with iV-bromosuccinimide (NBS) and water in DM SO or on reaction of 1-hydroxycyclopropylmethanol (122) with p-toluenesulphonyl chloride in pyridine (equation 93). ... 

Karahana ether (196), isolated from Japanese hops, is also a 1,1,2,3-tetra-methylcyclohexane derivative, and has been synthesised by Coates and Melvin by a route that they suggest may resemble the biogenetic pathway.Their synthesis consists in cyclising geranyl acetate (194) with benzoyl peroxide in the presence of cupric saltsand hydrolysing the resulting mixture to the corresponding diols, from which the cis-diol (195) is separated and converted to the ether with p-toluenesulphonyl chloride in pyridine at room temperature. 

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. 

First of all toluene is treated with chlorosulfonic acid to yield/ -toluenesulphonyl chloride, which on treatment with ammonia gives rise to the formation of/ -toluenesulphonamide. The resulting product on condensation with ethyl chloroformate in the presence of pyridine produces N-p-toluenesulphonyl carbamate with the loss of a mole of HCl. Further aminolysis of this product with butyl amine using ethylene glycol monomethyl ether as a reaction medium loses a mole of ethanol and yields tolbutamide. 

Generally similar to these reactions is that which occurs between pyridine oxides and pyridine in the presence of j -toluenesulphonyl chloride. Thus, 2-and 4-chloropyridine 1-oxide give 2-chloro-4- and 4-chloro-2-pyridyl-... 

An interesting reaction occurs with another quaternary salt from pyridine 1-oxide pyridine 1-oxide, j -toluenesulphonyl chloride and pyridine give... 

The reactions of pyridine 1-oxides with / -toluenesulphonyl chloride have produced complicated results . From pyridine 1-oxide a small amount of 3-pyridyl / -toluenesulphonate resulted, and 3-methylpyridine 1-oxide gave some 3-(5-methylpyridyl) / -toluenesulphonate, but a number of other substances were also formed. The 3-substituted pyridines have been represented as arising from an initial nucleophilic attack by chloride ion, and studies with labelled j -toluenesulphonyl chloride show that the subsequent step cannot involve a free sulphonate ion but may go through an... 

Add 1 g of the phenol to a mixture of 3 ml of pyridine and 2 g of p-toluenesulphonyl chloride. Heat on a water-bath for about 15 minutes, pom into 15 ml of water and stir well. Filter, wash the solid with dilute alkali and then with water. Recrystallize it from alcohol. 

Alcohols react with sulphonyl chlorides to yield sulphonate esters via Sn2 reaetions. Tosylate esters (alkyl tosylates) are formed from alcohols from the reaetion with p-toluenesulphonyl ehloride (TsCl). The reaction is most commonly carried out in the presenee of a base, e.g. pyridine or triethyla-mine (Et3N). 

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