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The Dakin-West reaction is a chemical reaction
Chemical reaction

A chemical reaction is a process that always results in the interconversion of chemical substances. The substance or substances initially involved in a chemical reaction are called reactants....
 that transforms an amino-acid into an amino-ketone
Ketone

In organic chemistry, a ketone is a type of organic compound which contains a carbonyl group bonded to two other carbon atoms in the form:Neither of the substituents R1 and R2 may be equal to hydrogen ....
 using a acid anhydride and a base, typically pyridine
Pyridine

Pyridine is a simple and important heterocyclic aromatic organic compound with the formula CarbonHydrogenNitrogen. This colorless liquid with a distinctive fish-like odor is structurally related to benzene, wherein one CH group in the six-membered ring is replaced by a nitrogen atom....
. It is named for Henry Drysdale Dakin
Henry Drysdale Dakin

Henry Drysdale Dakin was an England chemist.He was born in London as the youngest of 8 children to a family of steel merchants from Leeds. As a school boy he did water analysis with the Leeds City Analyst....
 (1880–1952) and Randolph West (1890–1949). Of special note, the amino-ketone product is always racemic
Racemic

In chemistry, a racemic mixture, or racemate, is one that has equal Amount of substance of left- and right-handed enantiomer of a Chirality molecule....
.

With pyridine as a base and solvent
Solvent

A solvent is a liquid or gas that dissolves a solid, liquid, or gaseous solute, resulting in a solution.The most common solvent in everyday life is water....
, refluxing conditions are required.






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The Dakin-West reaction is a chemical reaction
Chemical reaction

A chemical reaction is a process that always results in the interconversion of chemical substances. The substance or substances initially involved in a chemical reaction are called reactants....
 that transforms an amino-acid into an amino-ketone
Ketone

In organic chemistry, a ketone is a type of organic compound which contains a carbonyl group bonded to two other carbon atoms in the form:Neither of the substituents R1 and R2 may be equal to hydrogen ....
 using a acid anhydride and a base, typically pyridine
Pyridine

Pyridine is a simple and important heterocyclic aromatic organic compound with the formula CarbonHydrogenNitrogen. This colorless liquid with a distinctive fish-like odor is structurally related to benzene, wherein one CH group in the six-membered ring is replaced by a nitrogen atom....
. It is named for Henry Drysdale Dakin
Henry Drysdale Dakin

Henry Drysdale Dakin was an England chemist.He was born in London as the youngest of 8 children to a family of steel merchants from Leeds. As a school boy he did water analysis with the Leeds City Analyst....
 (1880–1952) and Randolph West (1890–1949). Of special note, the amino-ketone product is always racemic
Racemic

In chemistry, a racemic mixture, or racemate, is one that has equal Amount of substance of left- and right-handed enantiomer of a Chirality molecule....
.

Dakin West Reaction Scheme
With pyridine as a base and solvent
Solvent

A solvent is a liquid or gas that dissolves a solid, liquid, or gaseous solute, resulting in a solution.The most common solvent in everyday life is water....
, refluxing conditions are required. However, with the addition of 4-dimethylaminopyridine
4-Dimethylaminopyridine

4-Dimethylaminopyridine is a nucleophilic derivative of pyridine with the chemical formula 2NC5H4N. This colourless solid is a useful nucleophilic catalyst for a variety of reactions such as esterifications with anhydrides, the Baylis-Hillman reaction, hydrosilylations, tritylation, the Steglich rearrangemen...
 (DMAP) as a catalyst, the reaction can take place at room temperature.

With some acids, this reaction can take place even in the absence of an a-amino group.

This reaction should not be confused with the Dakin reaction
Dakin reaction

The Dakin reaction is the chemical reaction of phenolic aldehydes with hydrogen peroxide to form bisphenols and carboxylic acids. The reaction is named after Henry Drysdale Dakin....
.

Reaction mechanism

The reaction mechanism involves the acylation and activation of the acid 1 to the mixed anhydride 3. The amide will serve as a nucleophile for the cyclization forming the azlactone 4. Deprotonation and acylation of the azlactone forms the key carbon
Carbon

Carbon is a chemical element with chemical symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalence?making four electrons available to form covalent bond chemical bonds....
-carbon bond. Subsequent ring-opening of 6 and decarboxylation
Decarboxylation

Decarboxylation is any chemical reaction in which a carboxyl group is split off from a compound as carbon dioxide ....
 give the final amino-ketone product.

Dakin West Reaction Mechanism

General ketone synthesis

Modern variations on the Dakin-West reaction permit many enolizable carboxylic acids - not merely amino acids - to be converted to their corresponding methyl ketones. For example, ß-aryl carboxylic acids can be efficiently converted to ß-aryl ketones by treatment of an acetic anhydride solution of the acid with catalytic N-methylimidazole. This reactivity is attributed in part to generation of acetylimidazolium, a powerful cationic acetylating agent, in situ
In situ

In situ is a Latin phrase meaning in the place. It is used in many different contexts....
.