Pantoic acid

Pantoic acid is the alpha hydroxy acid with the formula HOCH₂C(CH₃)₂CH(OH)CO₂H. The compound is almost always encountered in a biological context, as an aqueous solution of its conjugate base pantoate HOCH₂C(CH₃)₂CH(OH)CO₂-. The amide of pantoic acid with β-alanine is pantothenic acid (vitamin B₅),^[1] a component of coenzyme A.

Pantoic acid

Names
Preferred IUPAC name (2R)-2,4-Dihydroxy-3,3-dimethylbutanoic acid
Other names D-Pantoic acid; D-Pantoate; B(R)-2,4-dihydroxy-3,3-dimethylbutanoic acid
Identifiers
CAS Number	1112-33-0 Y
3D model (JSmol)	Interactive image
ChemSpider	388387
PubChem CID	439251
UNII	0J1TL6G6J9 Y
CompTox Dashboard (EPA)	DTXSID70861968 DTXSID90963716, DTXSID70861968
InChI InChI=1S/C6H12O4/c1-6(2,3-7)4(8)5(9)10/h4,7-8H,3H2,1-2H3,(H,9,10)/t4-/m0/s1 Key: OTOIIPJYVQJATP-BYPYZUCNSA-N
SMILES O=C(O)[C@H](O)C(C)(C)CO
Properties
Chemical formula	C6H12O4
Molar mass	148.158 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Biosynthesis

Its biosynthesis proceeds from ketoisovalerate by hydroxymethylation:

(CH₃)₂CHC(O)CO₂⁻ + CH₂O → HOCH₂(CH₃)₂CC(O)CO₂⁻

This conversion is catalyzed by ketopantoate hydroxymethyltransferase, which gives ketopantoate. Ketopantoate is reduced by ketopantoate reductase to pantoate, using NADH as the hydride source.^[2]

The amide derived from pantoic acid and GABA is the pharmaceutical drug hopantenic acid.