4-Toluenesulfonyl chloride (''p''-toluenesulfonyl chloride, toluene-''p''-sulfonyl chloride) is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...

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 Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) a ...

and contains a

sulfonyl In organosulfur chemistry, a sulfonyl group can refer either to a functional group found primarily in sulfones, or to a substituent obtained from a sulfonic acid by the removal of the hydroxyl group, similarly to acyl groups. Sulfonyl groups c ...

chloride (−SO₂Cl)

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the re ...

Uses

In 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: :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 ''p''-Toluenesulfonyl hydrazide is the organic compound with the formula CH3C6H4SO2NHNH2. It is a white solid that is soluble in many organic solvents but not water or alkanes. It is a reagent in organic synthesis. Reactions With ketones and a ...

. 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 Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a ...

and

triethylamine Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA ...

. 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 Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized ...

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,

isocyanide An isocyanide (also called isonitrile or carbylamine) is an organic compound with the functional group –. It is the isomer of the related nitrile (–C≡N), hence the prefix is ''isocyano''.IUPAC Goldboo''isocyanides''/ref> The organic fragme ...

s and

diimide Diimide, also called diazene or diimine, is a compound having the formula (NH)2. It exists as two geometric isomers, ''E'' (''trans'') and ''Z'' (''cis''). The term diazene is more common for organic derivatives of diimide. Thus, azobenzene is ...

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

Manufacture

This 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 Saccharin (''aka'' saccharine, Sodium sacchari) is an artificial sweetener with effectively no nutritional value. It is about 550 times as sweet as sucrose but has a bitter or metallic aftertaste, especially at high concentrations. Saccharin is ...

), via the chlorosulfonation of

: : CH₃C₆H₅ + SO₂Cl₂ → CH₃C₆H₄SO₂Cl + HCl

Hazards

Tosyl chloride is considered to be a toxic and corrosive substance.4-Toluenesulfonyl chloride: main hazards

References

{{DEFAULTSORT:Toluenesulfonyl chloride, 4- Reagents for organic chemistry Sulfonyl halides p-Tosyl compounds Foul-smelling chemicals