Pimelic acid is the
organic compound with the
formula HO
2C(CH
2)
5CO
2H. Pimelic acid is one
unit longer than a related
dicarboxylic acid
In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (). The general molecular formula for dicarboxylic acids can be written as , where R can be aliphatic or aromatic. In general, dicarboxylic acids show ...
, adipic acid, a precursor to many polyesters and polyamides. However compared to adipic acid, pimelic acid is relatively small in importance industrially.
[ Derivatives of pimelic acid are involved in the biosynthesis of the ]amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −CO ...
and the vitamin biotin
Biotin (or vitamin B7) is one of the B vitamins. It is involved in a wide range of metabolic processes, both in humans and in other organisms, primarily related to the utilization of fats, carbohydrates, and amino acids. The name ''biotin'', bor ...
.
Synthesis
Biosynthesis
The biosynthesis of pimelic acid is unknown but is speculated to start with malonyl CoA
Malonyl-CoA is a coenzyme A derivative of malonic acid.
Functions
It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis.
Fatty acid biosynthesis
Malonyl-CoA provides 2-carbon units to fatty acids and commi ...
.
Chemical and industrial routes
Like other simple dicarboxylic acid
In organic chemistry, a dicarboxylic acid is an organic compound containing two carboxyl groups (). The general molecular formula for dicarboxylic acids can be written as , where R can be aliphatic or aromatic. In general, dicarboxylic acids show ...
s, many methods have been developed for producing pimelic acid.
Pimelic acid is produced commercially by oxidation of cycloheptanone
Cycloheptanone, (CH2)6CO, is a cyclic ketone also referred to as suberone. It is a colourless volatile liquid. Cycloheptanone is used as a precursor for the synthesis of pharmaceuticals.
Synthesis
In 1836, French chemist Jean-Baptiste Boussing ...
with dinitrogen tetroxide. Other routes include the relatively unselective oxidation of palmitic acid and the carbonylation
Carbonylation refers to reactions that introduce carbon monoxide into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbon ...
of caprolactone
ε-Caprolactone or simply caprolactone is a lactone (a cyclic ester) possessing a seven-membered ring. Its name is derived from caproic acid. This colorless liquid is miscible with most organic solvents and water. It was once produced on a large ...
.
Niche methods
Many other methods exist. Pimelic acid has been synthesized from cyclohexanone and from salicylic acid
Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Substa ...
. In the former route, the additional carbon is supplied by dimethyl oxalate, which reacts with the enolate.
In other syntheses, pimelic acid is made from cyclohexene-4-carboxylic acid, and a fourth method also exists based on the 1,4 reaction of malonate systems with acrolein
Acrolein (systematic name: propenal) is the simplest unsaturated aldehyde. It is a colorless liquid with a piercing, acrid smell. The smell of burnt fat (as when cooking oil is heated to its smoke point) is caused by glycerol in the burning fat ...
.
Several patents exist for the production of pimelic acid.
See also
* Diaminopimelic acid
Diaminopimelic acid (DAP) is an amino acid, representing an epsilon-carboxy derivative of lysine.
DAP is a characteristic of certain cell walls of some bacteria. DAP is often found in the peptide linkages of NAM-NAG chains that make up the cell ...
References
{{Authority control
Dicarboxylic acids