4-toluenesulfonyl chloride

4-Toluenesulfonyl chloride

Names
IUPAC name 4-methylbenzenesulfonyl chloride
Other names Tosyl chloride, p-toluenesulfonyl chloride, p-TsCl, TsCl
Identifiers
CAS Number	98-59-9 Y
3D model (JSmol)	Interactive image
ChemSpider	7119 Y
ECHA InfoCard	100.002.441
PubChem CID	160808444
InChI InChI=1S/C7H7ClO2S/c1-6-2-4-7(5-3-6)11(8,9)10/h2-5H,1H3 Y Key: YYROPELSRYBVMQ-UHFFFAOYSA-N Y InChI=1/C7H7ClO2S/c1-6-2-4-7(5-3-6)11(8,9)10/h2-5H,1H3 Key: YYROPELSRYBVMQ-UHFFFAOYAN
SMILES O=S(Cl)(=O)c1ccc(cc1)C
Properties
Chemical formula	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
Solubility in water	Hydrolysis
Hazards
Main hazards	Releases acid
NFPA 704	1 3 0
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).
N  (what is YN ?)
Infobox references

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. Abbreviated TsCl or TosCl, it is a derivative of toluene and contains a sulfonyl chloride (-SO₂Cl) functional group.

In characteristic manner, TsCl converts alcohols (abbreviated ROH) into the corresponding toluenesulfonate esters, or tosyl derivatives ("tosylates"):

Tosylates can be cleaved with lithium aluminium hydride:

Thus, tosylation followed by reduction allows for removal of a hydroxyl group.

Likewise, TsCl is used to prepare sulfonamides from amines:

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 highly effective by virtue of the trimethylamine.

Being 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. In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH₃C₆H₄SO₂Na.

TsCl is inexpensively available for laboratory use. It is a by-product from the production of o-toluenesulfonyl chloride (a precursor for the synthesis of saccharin), via the chlorosulfonation of toluene: