4-Toluenesulfonyl chloride
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| Names | |
|---|---|
| IUPAC name
4-Toluenesulfonyl chloride
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| Other names
Tosyl chloride, p-toluenesulfonyl chloride, p-TsCl, TsCl
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| Identifiers | |
3D model (JSmol)
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| ECHA InfoCard | 100.002.441 |
CompTox Dashboard (EPA)
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| Properties | |
| C7H7ClO2S | |
| Molar mass | 190.65 g/mol |
| Appearance | White solid |
| Melting point | 65-69 °C |
| Boiling point | 134 °C at 10 mmHg |
| hydrolysis | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
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releases acid |
| Flash point | 128 °C |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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4-Toluenesulfonyl chloride (p-toluenesulfonyl chloride, toluene-p-sulfonyl chloride) is an organic compound with the formula CH3C6H4SO2Cl. This colourless, malodorous solid is a reagent widely used in organic synthesis.[1] Abbreviated TsCl, it is a derivative of toluene and contains a sulfonyl chloride (-SO2Cl) functional group.
Use
Characteristically and usefully, 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:
- CH3C6H4SO2OR + 1/4 LiAlH4 → 1/4 LiAl(O3SC6H4CH3)4 + RH
Thus, tosylation followed by reduction allows for removal of a hydroxyl group.
Similarly, TsCl is used to prepare sulfonamides from amines:[2]
- CH3C6H4SO2Cl + RNH2 → CH3C6H4SO2NR2 + HCl
The resulting sulfonamides are non-basic and, when derived from primary amines, are even acidic.
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 reportedly highly effective by virtue of the trimethylamine.[1]
Other reactions
Being a widely available reagent, TsCl has been heavily examined from the perspective of reactivity. It is used in dehydrations to make nitriles, isocyanides, diimides.[1] In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH3C6H4SO2Na.[3]
Manufacture
TsCl is inexpensively available for laboratory use. It is a by-product from the production of o-toluenesulfonyl chloride, via the chlorosulfonation of toluene:[4]
- CH3C6H5 + SO2Cl2 → CH3C6H4SO2Cl + HCl
References
- ^ a b c D. Todd Whitaker, K. Sinclair Whitaker, Carl R. Johnson, Julia Haas, "p-Toluenesulfonyl Chloride" in Encyclopedia of Reagents for Organic Synthesis, 2006, John Wiley, New York. doi:10.1002/047084289X.rt136.pub2 Article Online Posting Date: September 15, 2006
- ^ Junji Ichikawa, Ryo Nadano, Takashi Mori, and Yukinori Wada (2006). "5-endo-trig Cyclization of 1,1-Difluoro-1-alkenes: Synthesis of 3-Butyl-2-Fluoro-1-Tosylindole". Organic Syntheses
{{cite journal}}: CS1 maint: multiple names: authors list (link). - ^ Frank C. Whitmore, Frances H. Hamilton (1941). "Sodium Toluenesulfinate". Organic Syntheses; Collected Volumes, vol. 1, p. 492.
- ^ Otto Lindner, Lars Rodefeld "Benzenesulfonic Acids and Their Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry 2001, Wiley-VCH, Weinheim. Published online: 15 September, 2000