para- Toluenesulfonyl chloride (tosyl chloride) is an organic compound, para-toluenesulfonic acid chloride , a reagent for the formation of derivatives of this sulfonic acid in reactions with compounds of various classes [1] .
Tosyl chloride | |
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Are common | |
| Systematic name | 4-toluenesulfonyl chloride |
| Chem. formula | C₇H₇ClO₂S |
Physical properties | |
| condition | white crystals |
| Molar mass | 190.66 g / mol |
Thermal properties | |
| T. melt. | 67—69 ℃ |
| T. bale. | 146 ℃ / 15 mmHg Art. |
Chemical properties | |
| Solubility in water | nr. water, p. ethanol, benzene, chloroform, diethyl ether |
Classification | |
| CAS Number | |
| PubChem | |
| ChemSpider | |
| EINECS Number | 202-684-8 |
Smiles | |
CC1 = CC = C (C = C1) S (= O) (= O) Cl | |
Inchi | |
1S / C7H7ClO2S / c1-6-2-4-7 (5-3-6) 11 (8.9) 10 / h2-5H, 1H3 | |
| Data is provided for standard conditions (25 ℃, 100 kPa) , unless otherwise indicated. | |
Cleaning
During prolonged storage, the compound decomposes with water to para-toluenesulfonic acid and hydrogen chloride . It can be purified by dissolving chloroform in a minimum amount, followed by filtration and dilution with a 5-fold volume of low-boiling petroleum ether to precipitate impurities. The resulting solution is filtered, decolorized with activated carbon and evaporated, obtaining a pure product in the form of white crystals [1] .
Also, tosyl chloride can be purified by recrystallization from petroleum ether, benzene or a mixture of toluene with petroleum ether. A solution of tosyl chloride in diethyl ether can be washed with a 10% NaOH solution, dried and the substance crystallized upon cooling on ice [1] .
Usage
A typical use of tosyl chloride is its reaction with alcohols , leading to the formation of para-toluenesulfonic acid esters (tosylation). Pyridine is used as the base in this reaction, and the optimum ratio of alcohol, tosyl chloride and pyridine is 1: 1.5: 2. With a good yield, tosylation can also be carried out in a heterophase system with the participation of benzyltriethylammonium chloride as a phase transfer catalyst [1] .
The tosylation reaction proceeds selectively with the participation of primary hydroxyl groups in the presence of secondary ones. There are also examples of selective tosylation of amino groups in the presence of hydroxyl groups and vice versa. The stereochemistry of the chiral carbon atom at the hydroxyl group during tosylation is not affected [1] .
Sometimes tosyl chloride acts as a chlorinating agent. In particular, its combination with 4-dimethylaminopyridine converts allyl, propargyl, and glycoside alcohols into the corresponding chlorides, while for secondary aliphatic hydroxyl groups the reaction stops at the tosylate stage [1] .
By mixing carboxylic acid with tosyl chloride in pyridine, symmetrical carboxylic acid anhydride can be efficiently obtained. If this is done in the presence of alcohol, an ester is obtained in high yield. This method is especially important for tertiary alcohols. During this reaction, the acid is constantly converted to anhydride in the presence of alcohol, which allows its use in the reaction to the fullest extent possible [1] .
Security
Tosyl chloride is sensitive to moisture and has a lacrimatory effect [1] .
Notes
- ↑ 1 2 3 4 5 6 7 8 Whitaker DT, Whitaker KS, Johnson CR, Haas J. p- Toluenesulfonyl Chloride: [ eng. ] // e-EROS Encyclopedia of Reagents for Organic Synthesis. - 2006. - DOI : 10.1002 / 047084289X.rt136.pub2 .