A beta hydroxy carboxylic acid or β-hydroxy carboxylic acid (BHA) is a

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl ...

containing a hydroxy

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

separated by ''two'' carbon atoms. They are related to

alpha hydroxy acid Alpha hydroxy carboxylic acids, or α-hydroxy carboxylic acids (AHAs), are a group of carboxylic acids featuring a hydroxy group located ''one'' carbon atom away from the acid group. This structural aspect distinguishes them from beta hydroxy aci ...

s, in which the two functional groups are separated by only ''one'' carbon atom.

Reactions

Upon

dehydration In physiology, dehydration is a lack of total body water that disrupts metabolic processes. It occurs when free water loss exceeds intake, often resulting from excessive sweating, health conditions, or inadequate consumption of water. Mild deh ...

, beta-hydroxy acids yield an alpha-beta unsaturated acid. Compared to their non-hydroxylated counterpart, beta hydroxy carboxylic acids are stronger, although weaker than the

s. Due to the larger distance, the intramolecular hydrogen bridge is less easily formed compared to the alpha hydroxy acids. The table summarizes some values on the propionic series. {, class="wikitable" ! Name ! p''K''_a , - ,

Propanoic acid Propionic acid (, from the Greek words πρῶτος : ''prōtos'', meaning "first", and πίων : ''píōn'', meaning "fat"; also known as propanoic acid) is a naturally occurring carboxylic acid with chemical formula . It is a liquid with a p ...

, , 4.87Handbook of Chemistry and Physics, CRC press, 58th edition page D150-151 (1977) , - , α-Hydroxypropionic acid , , 3.86Dawson, R. M. C. ''et al''., ''Data for Biochemical Research'', Oxford, Clarendon Press, 1959. , - , β-Hydroxypropionic acid , , 4.51

Occurrence and inventory

Aldonic acids, a type of

sugar acid In organic chemistry, a sugar acid or acidic sugar is a monosaccharide with a carboxyl group at one end or both ends of its Polymer backbone, chain. Main classes of sugar acids include: * Aldonic acids, in which the aldehyde group () located at t ...

, are a class of naturally occurring β-hydroxycarboxylic acids. They have the general chemical formula HO₂C(CHOH)_nCH₂OH.

Gluconic acid Gluconic acid is an organic compound with molecular formula C6H12O7 and condensed structural formula HOCH2(CHOH)4CO2H. A white solid, it forms the gluconate anion in neutral aqueous solution. The salts of gluconic acid are known as "gluconates" ...

, a particularly common aldonic acid, the oxidized derivative of

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

. Other beta hydroxy acids include: * β-Hydroxybutyric acid *

3-Hydroxypentanoic acid 3-Hydroxyvaleric acid (3-hydroxypentanoic acid) is the organic compound with the formula . It is one of the hydroxypentanoic acids. It is made from odd carbon fatty acids in the liver and rapidly enters the brain. As opposed to 4-carbon ketone ...

3-Hydroxyoctanoic acid 3-Hydroxyoctanoic acid is a beta-hydroxy acid that is naturally produced in humans, other animals, and plants. 3-Hydroxyoctanoic acid is the primary endogenous agonist of hydroxycarboxylic acid receptor 3 (HCA3), a G protein-coupled receptor pro ...

3-Hydroxydecanoic acid Myrmicacin (3-hydroxydecanoic acid) is a chemical compound of the β-hydroxycarboxylic acid class. It is named after the South American leaf-cutter ants (Myrmicinae) in which it was first discovered, but is also found in royal jelly. Myrmicacin i ...

* β-Hydroxy β-methylbutyric acid *

Carnitine Carnitine is a quaternary ammonium compound involved in metabolism in most mammals, plants, and some bacteria. In support of energy metabolism, carnitine transports long-chain fatty acids from the cytosol into mitochondria to be oxidized for f ...

Salicylic acid Salicylic acid is an organic compound with the formula HOC6H4COOH. A colorless (or white), bitter-tasting solid, it is a precursor to and a active metabolite, metabolite of acetylsalicylic acid (aspirin). It is a plant hormone, and has been lis ...

, a β-hydroxy acid. In cosmetics, the term ''beta hydroxy acid'' refers specifically to salicylic acid, which is used in some "anti-aging" creams and

acne Acne ( ), also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, ...

treatments. It is used to combat inflammation.

References

ar:حمض هيدروكسي

Reactions

Occurrence and inventory

See also

References