4-Toluenesulfonyl chloride
Encyclopedia
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
. Abbreviated TsCl or TosCl, it is a derivative of toluene
and contains a sulfonyl chloride (-SO2Cl) functional group
.
s (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 sulfonamide
s 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
.
s, isocyanide
s, diimides. In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH3C6H4SO2Na.
), via the chlorosulfonation of toluene:
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with the formula CH3C6H4SO2Cl. This colourless, malodorous solid is a reagent
Reagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
widely used in organic synthesis
Organic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
. Abbreviated TsCl or TosCl, it is a derivative of toluene
Toluene
Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.It is an aromatic...
and contains a sulfonyl chloride (-SO2Cl) functional group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
.
Uses
In characteristic manner, TsCl converts alcoholAlcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s (abbreviated ROH) into the corresponding toluenesulfonate esters, or tosyl derivatives ("tosylates"):
- CH3C6H4SO2Cl + ROH → CH3C6H4SO2OR + HClHydrogen chlorideThe compound hydrogen chloride has the formula HCl. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric humidity. Hydrogen chloride gas and hydrochloric acid are important in technology and industry...
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
Sulfonamide (chemistry)
In chemistry, the sulfonamide functional group is -S2-NH2, a sulfonyl group connected to an amine group.A sulfonamide is a compound that contains this group. The general formula is RSO2NH2, where R is some organic group. For example, "methanesulfonamide" is CH3SO2NH2...
from amines:
- CH3C6H4SO2Cl + R2NH → CH3C6H4SO2NR2 + HCl
The resulting sulfonamide
Sulfonamide (chemistry)
In chemistry, the sulfonamide functional group is -S2-NH2, a sulfonyl group connected to an amine group.A sulfonamide is a compound that contains this group. The general formula is RSO2NH2, where R is some organic group. For example, "methanesulfonamide" is CH3SO2NH2...
s 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
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...
and triethylamine
Triethylamine
Triethylamine is the chemical compound with the formula N3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine, for which TEA is also a common abbreviation....
. 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
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...
.
Other reactions
Being a widely available reagent, TsCl has been heavily examined from the perspective of reactivity. It is used in dehydrations to make nitrileNitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...
s, isocyanide
Isocyanide
An isocyanide is an organic compound with the functional group -N≡C. It is the isomer of the related cyanide , hence the prefix iso....
s, diimides. In an unusual reaction focusing on the sulfur center, zinc reduces TsCl to the sulfinate, CH3C6H4SO2Na.
Manufacture
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 saccharinSaccharin
Saccharin is an artificial sweetener. The basic substance, benzoic sulfilimine, has effectively no food energy and is much sweeter than sucrose, but has a bitter or metallic aftertaste, especially at high concentrations...
), via the chlorosulfonation of toluene:
- CH3C6H5 + SO2Cl2 → CH3C6H4SO2Cl + HCl