1,3-Butanediol

1,3-Butanediol is an organic compound with the formula CH₃CH(OH)CH₂CH₂OH, not to be confused with 1,4 Butanediol. With two alcohol functional groups, the molecule is classified as a diol. The compound without the R (or D) designation is racemic, which is what has been used in most studies before 2023. The compound is a colorless, bittersweet, water-soluble liquid. It is one of four common structural isomers of butanediol.^[1][2][3] It is used in grape flavoring,^[4] and as a precursor to some antibiotics.^[5]

1,3-Butanediol

Skeletal formula of 1,3-butanediol
Ball and stick model of 1,3-butanediol (S) Spacefill model of 1,3-butanediol (S)
Names
Preferred IUPAC name Butane-1,3-diol
Other names 1,3-butylene glycol, butane-1,3-diol, or 1,3-dihydroxybutane
Identifiers
CAS Number	107-88-0 Y 6290-03-5 (R) Y 24621-61-2 (S) Y
3D model (JSmol)	Interactive image
Beilstein Reference	1731276 1718944 (R) 1718943 (S)
ChEBI	CHEBI:52683 N
ChEMBL	ChEMBL1231503 N
ChemSpider	7608 Y 553103 (R) Y 394191 (S) Y
DrugBank	DB02202 N
ECHA InfoCard	100.003.209
EC Number	203-529-7
E number	E1502 (additional chemicals)
Gmelin Reference	2409 2493173 (R) 1994384 (S)
KEGG	D10695 N
MeSH	1,3-Butylene+glycol
PubChem CID	7896 637497 (R) 446973 (S)
RTECS number	EK0440000
UNII	3XUS85K0RA Y
CompTox Dashboard (EPA)	DTXSID8026773
InChI InChI=1S/C4H10O2/c1-4(6)2-3-5/h4-6H,2-3H2,1H3 N Key: PUPZLCDOIYMWBV-UHFFFAOYSA-N N
SMILES CC(O)CCO
Properties
Chemical formula	C4H10O2
Molar mass	90.122 g·mol−1
Appearance	Colourless liquid
Density	1.0053 g cm−3
Melting point	−50 °C (−58 °F; 223 K)
Boiling point	204 to 210 °C; 399 to 410 °F; 477 to 483 K
Solubility in water	1 kg dm−3
log P	−0.74
Vapor pressure	8 Pa (at 20 °C)
Refractive index (nD)	1.44
Thermochemistry
Std molar entropy (S⦵298)	227.2 J K−1 mol−1
Std enthalpy of formation (ΔfH⦵298)	−501 kJ mol−1
Std enthalpy of combustion (ΔcH⦵298)	−2.5022 MJ mol−1
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H319, H413
Precautionary statements	P305+P351+P338
NFPA 704 (fire diamond)	1 1 0
Flash point	108 °C (226 °F; 381 K)
Autoignition temperature	394 °C (741 °F; 667 K)
Related compounds
Related butanediol	1,2-Butanediol 1,4-Butanediol 2,3-Butanediol
Related compounds	2-Methylpentane
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

Production and uses

Hydrogenation of 3-hydroxybutanal gives 1,3-butanediol:^[6]

CH₃CH(OH)CH₂CHO + H₂ → CH₃CH(OH)CH₂CH₂OH

Dehydration of 1,3-butanediol gives 1,3-butadiene:

CH₃CH(OH)CH₂CH₂OH → CH₂=CH-CH=CH₂ + 2 H₂O

Pharmacology

1,3-Butanediol has sedative, hypotensive and hypoglycaemic action comparable to ethanol, with the (R), also known as (D), enantiomer being more active.^[7][8] Fatty acid esters of 1,3-butanediol such as the acetoacetate, lactate or hexanoate have been researched for inducing ketogenesis.^{[9][10][11][12][13][14][15]} Recent research highlights the stereospecific metabolism of (R)-1,3-butanediol, emphasizing its efficient conversion to β-hydroxybutyrate via alcohol dehydrogenase. This process involves zinc coordination and maintains cellular redox balance. Notably, (R)-1,3-butanediol induces mild euphoric effects through ketone body signaling pathways, distinct from the GABAergic mechanisms associated with ethanol.^[16]

Occurrence

1,3-Butanediol has been detected in green bell peppers, orange bell peppers, pepper (Capsicum annuum), red bell peppers, and yellow bell peppers.^[17] 1,3 Butanediol, | quote = Also referred to as 1,3-Butylene glycol, maintains FDA GRAS status as a flavor molecule.^[18]

Biochemistry

The metabolism of (R)-1,3-butanediol is compartmentalized within hepatic cells, occurring in both cytosolic and mitochondrial domains. Enzymatic studies have quantified the distribution of alcohol dehydrogenase isoforms involved in its conversion to β-hydroxybutyrate, underscoring the molecule's potential in therapeutic ketone body production.^[16]