Tosyl
Encyclopedia
A tosyl group is CH3C6H4SO2. This group is usually derived from the compound 4-toluenesulfonyl chloride
, CH3C6H4SO2Cl, which forms esters and amides of toluenesulfonic or tosylic acid. The para orientation
illustrated (p-toluenesulfonyl) is most common, and by convention tosyl refers to the p-toluenesulfonyl group.
Tosylate refers to the anion of p-toluenesulfonic acid (CH3C6H4SO3−) and it is abbreviated as TsO−, or it may refer to ester
s of p-toluenesulfonic acid.
, alkyl alcohols can also be converted to alkyl tosylates. This is useful because alcohols are poor leaving groups in SN2 reactions, as opposed to the tosylate group which poses as a good leaving group. It is the transformation of alkyl alcohols to alkyl tosylates that allows an SN2 reaction to occur in the presence of a good nucleophile.
A tosyl group can function as a protecting group
in organic synthesis. Alcohols can be converted to tosylate groups so that they do not react. The tosylate group may later be converted back into an alcohol. The use of these functional groups is exemplified in organic synthesis
of the drug tolterodine
, wherein one of the steps a phenol
group is protected as its tosylate and the primary alcohol
as its nosylate. The latter is a leaving group for displacement by diisopropylamine
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4-Toluenesulfonyl chloride
4-Toluenesulfonyl chloride is an organic compound with the formula CH3C6H4SO2Cl. This colourless, malodorous solid is a reagent widely used in organic synthesis...
, CH3C6H4SO2Cl, which forms esters and amides of toluenesulfonic or tosylic acid. The para orientation
Arene substitution patterns
Arene substitution patterns are part of organic chemistry IUPAC nomenclature and pinpoint the position of substituents other than hydrogen in relation to each other on an aromatic hydrocarbon.- Ortho, meta, and para substitution :...
illustrated (p-toluenesulfonyl) is most common, and by convention tosyl refers to the p-toluenesulfonyl group.
Tosylate refers to the anion of p-toluenesulfonic acid (CH3C6H4SO3−) and it is abbreviated as TsO−, or it may refer to ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
s of p-toluenesulfonic acid.
Applications
For SN2 reactionsSN2 reaction
The SN2 reaction is a type of nucleophilic substitution, where a lone pair from a nucleophile attacks an electron deficient electrophilic center and bonds to it, expelling another group called a leaving group. Thus the incoming group replaces the leaving group in one step...
, alkyl alcohols can also be converted to alkyl tosylates. This is useful because alcohols are poor leaving groups in SN2 reactions, as opposed to the tosylate group which poses as a good leaving group. It is the transformation of alkyl alcohols to alkyl tosylates that allows an SN2 reaction to occur in the presence of a good nucleophile.
A tosyl group can function as a protecting group
Protecting group
A protecting group or protective group is introduced into a molecule by chemical modification of a functional group in order to obtain chemoselectivity in a subsequent chemical reaction...
in organic synthesis. Alcohols can be converted to tosylate groups so that they do not react. The tosylate group may later be converted back into an alcohol. The use of these functional groups is exemplified 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...
of the drug tolterodine
Tolterodine
Tolterodine is an antimuscarinic drug that is used to treat urinary incontinence.It is marketed by Pfizer in Canada and the United States by its brand name Detrol. In Egypt it is also found under the trade names Tolterodine by Sabaa and Incont L.A...
, wherein one of the steps a phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
group is protected as its tosylate and the primary alcohol
Alcohol
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....
as its nosylate. The latter is a leaving group for displacement by diisopropylamine
Diisopropylamine
Diisopropylamine is a secondary amine with the chemical formula 2HC-NH-CH2. It is best known as its lithium salt, lithium diisopropylamide, known as "LDA"...
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