4-Toluenesulfonyl chloride (p-toluenesulfonyl chloride, toluene-p-sulfonyl chloride) is an organic compound with the formula CH3C6H4SO2Cl. This white, malodorous solid is a reagent widely used in organic synthesis.[2] Abbreviated TsCl or TosCl, it is a derivative of toluene and contains a sulfonyl chloride (−SO2Cl) functional group.
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| Names | |
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| Preferred IUPAC name
4-Methylbenzene-1-sulfonyl chloride | |
| Other names
Tosyl chloride, p-toluenesulfonyl chloride, p-TsCl, TsCl
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.002.441 |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C7H7ClO2S | |
| Molar mass | 190.65 g/mol |
| Appearance | White solid |
| Melting point | 65 to 69 °C (149 to 156 °F; 338 to 342 K) |
| Boiling point | 134 °C (273 °F; 407 K) at 10 mmHg |
| Reacts with water | |
| Hazards[1] | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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Releases HCl on contact with water |
| NFPA 704 (fire diamond) | |
| Flash point | 128 °C (262 °F; 401 K) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Uses
editIn characteristic manner, TsCl converts alcohols (abbreviated ROH) into the corresponding toluenesulfonate esters, or tosyl derivatives ("tosylates"):
- CH3C6H4SO2Cl + ROH → CH3C6H4SO2OR + HCl
Tosylates can be cleaved with lithium aluminium hydride:
- 4 CH3C6H4SO2OR + LiAlH4 → LiAl(O3SC6H4CH3)4 + 4 RH
Thus, tosylation followed by reduction allows for removal of a hydroxyl group.
Likewise, TsCl is used to prepare sulfonamides from amines:[3]
- CH3C6H4SO2Cl + R2NH → CH3C6H4SO2NR2 + HCl
The resulting sulfonamides are non-basic and, when derived from primary amines, are even acidic.
TsCl reacts with hydrazine to give p-toluenesulfonyl hydrazide.
The preparation of tosyl esters and amides are conducted in the presence of a base, which absorbs hydrogen chloride. The selection of the base is often crucial to the efficiency of tosylation. Typical bases include pyridine and triethylamine. Unusual bases are also used; for example, catalytic amounts of trimethylammonium chloride in the presence of triethylamine is highly effective by virtue of the trimethylamine.[2]
Other reactions
editBeing a widely available reagent, TsCl has been heavily examined from the perspective of reactivity. It is used in dehydrations to make nitriles, isocyanides and diimides.[2] In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH3C6H4SO2Na.[4]
Manufacture
editThis reagent is inexpensively available for laboratory use. It is a by-product from the production of ortho-toluenesulfonyl chloride (a precursor for the synthesis of the common food additive and catalyst saccharin), via the chlorosulfonation of toluene:[5]
- CH3C6H5 + SO2Cl2 → CH3C6H4SO2Cl + HCl
Hazards
editTosyl chloride is "a corrosive lachrymator."[2]
References
edit- ^ "P-TOLUENESULFONYL CHLORIDE (TOSYL CHLORIDE)".
- ^ a b c d Whitaker, D. T.; Whitaker, K. S.; Johnson, C. R.; Haas, J. (2006). "P-Toluenesulfonyl Chloride". p-Toluenesulfonyl Chloride. Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley. doi:10.1002/047084289X.rt136.pub2. ISBN 978-0471936237. Archived from the original on 2016-03-05. Retrieved 2013-05-28.
- ^ Ichikawa, J.; Nadano, R.; Mori, T.; Wada, Y. (2006). "5-endo-trig Cyclization of 1,1-Difluoro-1-alkenes: Synthesis of 3-Butyl-2-Fluoro-1-Tosylindole". Organic Syntheses. 83: 111; Collected Volumes, vol. 11, p. 834.
- ^ Whitmore, F. C.; Hamilton, F. H. (1922). "Sodium Toluenesulfinate". Organic Syntheses. 2: 89; Collected Volumes, vol. 1, p. 492.
- ^ Lindner, O.; Rodefeld, L. "Benzenesulfonic Acids and Their Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_507. ISBN 978-3527306732.