Isovaleric acid

3-Methylbutanoic acid

Names
IUPAC name 3-Methylbutanoic acid
Other names Delphinic acid 3-Methylbutyric acid Isopentanoic acid
Identifiers
CAS Number	503-74-2 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:28484 Y
ChemSpider	10001 Y
DrugBank	DB03750 Y
ECHA InfoCard	100.007.251
KEGG	C08262 Y
PubChem CID	10430
UNII	1BR7X184L5 Y
InChI InChI=1S/C5H10O2/c1-4(2)3-5(6)7/h4H,3H2,1-2H3,(H,6,7) Y Key: GWYFCOCPABKNJV-UHFFFAOYSA-N Y InChI=1/C5H10O2/c1-4(2)3-5(6)7/h4H,3H2,1-2H3,(H,6,7) Key: GWYFCOCPABKNJV-UHFFFAOYAV
SMILES O=C(O)CC(C)C
Properties
Chemical formula	C5H10O2
Molar mass	102.13 g/mol
Density	0.925 g/cm3
Melting point	−29 °C (−20 °F; 244 K)
Boiling point	175 to 177 °C (347 to 351 °F; 448 to 450 K)
Magnetic susceptibility (χ)	-67.7·10−6 cm3/mol
Related compounds
Related carboxylic acids	butyric acid β-hydroxybutyric acid β-hydroxy β-methylbutyric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

3-Methylbutanoic acid, also known as β-methylbutyric acid or more commonly isovaleric acid, is an organic compound with the formula (CH₃)₂CHCH₂CO₂H. It is sometimes classified as a fatty acid. It is a colourless liquid that is sparingly soluble in water, but highly soluble in most common organic solvents. The compound occurs naturally, including in essential oils.

Isovaleric acid has a strong pungent cheesy or sweaty smell, but its volatile esters have pleasing scents and are used widely in perfumery. It has been proposed that it is the anticonvulsant agent in valerian. It is a major component of the cause of unpleasant foot odor, as it is produced by skin bacteria metabolizing leucine.

Isovaleric acid is seen as the primary cause of the flavors added to wine caused by Brettanomyces yeasts. Other compounds produced by Brettanomyces yeasts include 4-ethylphenol, 4-vinylphenol, and 4-ethylguaiacol. An excess of isovaleric acid in wine is generally seen as a defect, as it can smell sweaty, leathery, or like a barnyard, but in small amounts it can smell smokey, spicy, or medicinal. These phenomena may be prevented by killing any Brettanomyces yeasts, such as by sterile filtration, by the addition of relatively large quantities of sulfur dioxide and sometimes sorbic acid, by mixing in alcoholic spirit to give a fortified wine of sufficient strength to kill all yeast and bacteria, or by pasteurization. Isovaleric acid can also be found in beer, and, excepting some English–style ales, is usually considered a flaw. It can be produced by the oxidation of hop resins, or by Brettanomyces yeasts present.

Isovaleric acid has been used to synthesize β-hydroxyisovaleric acid – otherwise known as β-hydroxy β-methylbutyric acid – via microbial oxidation by the fungus Galactomyces reessii.