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 CH
3C
6H
4SO
2Cl. 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 (−SO
2Cl)
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"):
: CH
3C
6H
4SO
2Cl + ROH → CH
3C
6H
4SO
2OR +
HCl
Tosylates can be cleaved with lithium aluminium hydride:
: 4 CH
3C
6H
4SO
2OR + LiAlH
4 → LiAl(O
3SC
6H
4CH
3)
4 + 4 RH
Thus, tosylation followed by reduction allows for removal of a hydroxyl group.
Likewise, TsCl is used to prepare
sulfonamides from amines:
:CH
3C
6H
4SO
2Cl + R
2NH → CH
3C
6H
4SO
2NR
2 + 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 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 ...
:
: 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