P-Toluenesulfinic acid

A mixture of 10 g. (1.1 mole) of toluene, 40 g. of carbon disulfide (Caution—toxic volatile substance) and 15 g. (1.1 mole) of aluminum chloride is cooled to —10°, and dry hydrogen chloride gas is introduced for 5 minutes. Hood.) Sulfur dioxide is then introduced for 2 hours, and the mixture is allowed to stand for 12 hours, after which it is poured on ice. Sodium carbonate is added until the mixture is alkaline, and the carbon disulfide is removed by steam distillation. The alumina is removed from the reaction mixture by filtration, and the filtrate is evaporated to a volume of 150 ml. Addition of hydrochloric acid precipitates 16 g. (94%) of p-toluenesulfinic acid melting at 84°. 

A solution of 49 g. (0.75 mole) of potassium cyanide in 120 ml. of water and 400 ml. of ethanol is stirred and heated to boiling. Powdered a-bromo-m-xylene (128 g., 0.69 mole) (p. 105) is added as rapidly as the vigorous exothermic nature of the reaction will allow. The reaction mixture is filtered hot, and the filtrate is diluted with 1 1. of water. Extraction with ether followed by drying and distillation of the ethereal solution gives an 85% yield of w-tolylaceto-nitrile boiling at 245-247°/745 mm. The product boils at 133°/15 mm. 

A mixture of 41 g. (0.25 mole) of trichloroacetic acid and 53 g. (0.375 mole) of benzoyl chloride is placed under an efficient fractionating column and heated. The trichloroacetyl chloride is removed from the top of the column as rapidly as it is formed. The head temperature should not be allowed to go above 119°. The distillate is redistilled through the same column. During the first part of the distillation, a high reflux ratio should be maintained, since in this way hydrogen chloride present in the material from the first distillate is eliminated. There is obtained 23 g. (51%) of trichloroacetyl chloride boiling at 116-119° at atmospheric pressure. 

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There are dubious claims for the displacement of the A7-fluorine in perfluoroazetine (240) (60DOK(l3l)l338) by ethanol and for the formation of an azete by reaction of the bicyclic azetine (241) with base. An attempt to produce azete by elimination of p-toluenesulfinic acid from azetine (237 Z = Ts) failed (7UOC435). 

Preparation of enantiomerically pure sulfmate esters has most often been accomplished by making menthyl esters of arenesulfinic acids, particularly of p-toluenesulfinic acid. This... 

Benzaldehyde reacts with formamide and MesSiCl 14 on heating to give, via 435, the N,N-acetal 469, which reacts in situ with p-toluenesulfinic acid, in high yields, to give 470 [58]. The analogous reaction of excess a,)9-unsaturated ahphatic primary amide with aliphatic aldehydes in the presence of TMSOTf 20 in 1,2-di-chloroethane at 25 °C affords the unsaturated N,N-acetals in high yield [58 a]. Benzaldehyde also condenses with excess HMDS 2, in the presence of catalytic amounts of ZnCl2, via 471, to 472 and HMDSO 7 [59] (Scheme 5.21). 

A very surprising sulfone formation has been investigated by Oae and coworkers . On heating p-toluenesulfinic acid with dimethylaniline in ethanol for 15 h, the reaction mixture shown in equation 100 has been obtained. Obviously, the observed products arise from an equilibrium between the sulfinic acid and its pseudo-anhydride (disulfide trioxide), which is able to attack the amine nitrogen and degrade the tertiary amine corresponding to a Polonovsky reaction . 

Esterification of p-toluenesulfinic acid with (- )-menthol gives a mixture of two diastereomers, which equilibrate to the pure (-)-menthyl (S)-p-toluenesulfinate diastereomer in the presence of hydrochloric acid (80% yield). The report includes an improved procedure for reaction of 1 with CH,MgI to give (R)-( + )-methyl p-tolyl sulfoxide.1... 

The first MCR involving the explicit use of a-acidic isonitriles was reported in 1998 by Sisko [131]. The reaction involves the cycloaddition of aTosMIC derivative (8) to an (in situ-generated) imine (10) followed by the elimination of p-toluenesulfinic acid (TsH) as described in 1977 by van Leusen for preformed imines (Fig. 5, scaffold P) [119]. Although several potential pitfalls for the conversion of the traditional van Leusen [3 + 2] cycloaddition to the so-called van Leusen three-component reaction (vL-3CR) of imidazoles were expected by the author, simply stirring the aldehyde and amine for 20 min followed by addition of the TosMIC derivative and base resulted in the isolation of the corresponding imidazole (9) in high yield [131]. 

Neopentyl tosylate p-Toluenesulfinic acid, neopentyl ester (8) Benzenesulfinic acid, 4-methyl-2,2-dimethylpropyl ester (9) (13146-08-2)... 

The reaction of tertiary amides of p-toluenesulfinic acid with sulfur tetrafluoride proceeds with cleavage of the S-N bond to give aminosulfur trifluorides 8 and p-toluenesulfinyl fluoride in good yield. The products can be readily separated by distillation.213... 

A. p-Toluenesulfinic acid( 1). A 2-L Erlenmeyer flask equipped with a magnetic stir bar is charged with 670 mL of water and 134.1 g (536 mmol) of p-toluenesulfinic acid, sodium salt (Note 1) and the mixture is stirred for 20-30 min until a clear solution... 

Minor decomposition of p-toluenesulfinic acid is observed at temperatures above 55°C. For this reason, the water bath of the rotary evaporator and all subsequent heating operations should be kept at temperatures below 35-40°C to obtain best results. 

The 50 mol % excess of p-toluenesulfinic acid is required to obtain the best results. Using only 10-20 mole % excess of the sulfinic acid typically lowers the yield by 20-30%. This has been attributed to the known propensity of arylsulfinic acids to disproportionate.3 The checkers noted the presence of insoluble material after the addition of p-toluenesulfinic acid. This did not effect the yield. 

Recently, the reaction of DMAD with pyridinium arylsulfonyl methylides has been used as a simple route to indolizines.63 The intermediate dihydroindolizines are readily aromatized by 1,4-elimination of p-toluenesulfinic acid. 

O-and S-Akylation. This base facilitates esterification of carboxylic acids1 and S-alkylation of p-toluenesulfinic acids.2... 

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