Allantoin is a chemical compound with formula C₄H₆N₄O₃. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a diureide of glyoxylic acid. Allantoin is a major metabolic intermediate in most organisms including animals, plants and bacteria. It is produced from uric acid, which itself is a degradation product of nucleic acids, by action of urate oxidase (uricase). The occurs as a natural mineral compound (IMA symbol Aan).

Allantoin

Names
IUPAC name (2,5-Dioxo-4-imidazolidinyl) urea
Other names Glyoxyldiureide; 5-Ureidohydantoin
Identifiers
CAS Number	97-59-6 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:15676 Y
ChEMBL	ChEMBL593429 Y
ChemSpider	199 Y
ECHA InfoCard	100.002.358
EC Number	202-592-8
KEGG	D00121 Y
PubChem CID	204
RTECS number	YT1600000
UNII	344S277G0Z Y
CompTox Dashboard (EPA)	DTXSID3020043
InChI InChI=1S/C4H6N4O3/c5-3(10)6-1-2(9)8-4(11)7-1/h1H,(H3,5,6,10)(H2,7,8,9,11) Y Key: POJWUDADGALRAB-UHFFFAOYSA-N Y InChI=1/C4H6N4O3/c5-3(10)6-1-2(9)8-4(11)7-1/h1H,(H3,5,6,10)(H2,7,8,9,11) Key: POJWUDADGALRAB-UHFFFAOYAE
SMILES O=C1NC(=O)NC1NC(=O)N C1(C(=O)NC(=O)N1)NC(=O)N
Properties
Chemical formula	C4H6N4O3
Molar mass	158.117 g·mol−1
Appearance	colourless crystalline powder
Odor	odorless
Density	1.45 g/cm3
Melting point	230 °C (446 °F; 503 K) (decomposes)
Boiling point	478 °C (892 °F; 751 K)[dubious – discuss]
Solubility in water	0.57 g/100 mL (25 °C) 4.0 g/100 mL (75 °C)
Solubility	soluble in alcohol, pyridine, NaOH insoluble in ethyl ether
log P	-3.14
Acidity (pKa)	8.48
Hazards
NFPA 704 (fire diamond)	2 1 0
Lethal dose or concentration (LD, LC):
LD50 (median dose)	> 5000 mg/kg (oral, rat)
Safety data sheet (SDS)	Allantoin MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references