Hexane-2,5-dione

Hexane-2,5-dione
Names
	Preferred IUPAC name Hexane-2,5-dione
	Other names 1,2-Diacetylethane; 'α','β'-Diacetylethane; Acetonyl acetone; Diacetonyl; 2,5-Dioxohexane; 2,5-Diketohexane; 2,5-Hexanedione
Identifiers
CAS Number	110-13-4 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:85014 ;
ChemSpider	7744 ;
ECHA InfoCard	100.003.400
EC Number	203-738-3;
PubChem CID	8035;
RTECS number	MO3150000;
UNII	C0Z8884J3P ;
UN number	1224
CompTox Dashboard (EPA)	DTXSID8030138 ;
	InChI InChI=1S/C6H10O2/c1-5(7)3-4-6(2)8/h3-4H2,1-2H3 Key: OJVAMHKKJGICOG-UHFFFAOYSA-N ; InChI=1/C6H10O2/c1-5(7)3-4-6(2)8/h3-4H2,1-2H3 Key: OJVAMHKKJGICOG-UHFFFAOYAH;
	SMILES O=C(C)CCC(=O)C;
Properties
Chemical formula	C6H10O2
Molar mass	114.1438 g mol−1
Appearance	colorless liquid
Density	0.973 g cm−3, liquid
Melting point	−5.5 °C (22.1 °F; 267.6 K)
Boiling point	191.4 °C (376.5 °F; 464.5 K)
Solubility in water	≥ 10 g/100 mL (22 °C)
Magnetic susceptibility (χ)	-62.51·10−6 cm3/mol
Structure
Molecular shape	trigonal planar at carbonyl; tetrahedral elsewhere
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H373
Precautionary statements	P260, P264, P280, P302+P352, P305+P351+P338, P314, P321, P332+P313, P337+P313, P362, P501
Flash point	78 °C (172 °F; 351 K)
Related compounds
Related diketones	acetylacetone
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

2,5-Hexanedione (Acetonylacetone) is an aliphatic diketone. It is a colorless liquid.^[1] In humans, it is a toxic metabolite of hexane and of 2-hexanone.

Symptoms of poisoning

The chronic toxicity of hexane is attributed to hexane-2,5-dione. The symptoms are tingling and cramps in the arms and legs, followed by general muscular weakness. In severe cases, atrophy of the skeletal muscles is observed, along with a loss of coordination and vision problems.^[2]

Similar symptoms are observed in animal models. They are associated with a degeneration of the peripheral nervous system (and eventually the central nervous system), starting with the distal portions of the longer and wider nerve axons.

Mechanism of action

It appears that the neurotoxicity of 2,5-hexanedione resides in its γ-diketone structure since 2,3-, 2,4-hexanedione and 2,6-heptanedione are not neurotoxic, whereas 2,5-heptanedione and 3,6-octanedione and other γ-diketones are.^[3]

2,5-Hexanedione reacts with lysine residues in axonal proteins by Schiff base formation followed by cyclization to give pyrroles. Oxidation of the pyrrole residues then causes cross-linking and denaturation of proteins, which perturbs axonal transport and function and causes damage to nerve cells.^[4]

Synthesis

2,5-Hexanedione has been prepared in several ways.^[5] A common method involves hydrolysis of 2,5-dimethylfuran, a glucose derived heterocycle.^[1]

Uses

Acetonylacetone can be used in the synthesis of isocarboxazid,^[6] rolgamidine,^[7] and mopidralazine. Treatment with P₄S₁₀ gives 2,5-dimethylthiophene.

References

^ ^a ^b Young, D. M.; Allen, C. F. H. (1936). "2,5-Dimethylpyrrole". Organic Syntheses. 16: 25. doi:10.15227/orgsyn.016.0025.
^ Couri D, Milks M. "Toxicity and metabolism of the neurotoxic hexacarbons n-hexane, 2-hexanone, and 2,5-hexanedione" Annu. Rev. Pharmacol. Toxicol. 1982;22:145-66.
^ Stephen R Clough; Leyna Mulholland (2005), "Hexane", Encyclopedia of Toxicology, vol. 2 (2nd ed.), Elsevier, pp. 522–525
^ Wolfgang Dekant; Spiridon Vamvakas (2007). "Toxicology". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. p. 23. ISBN 978-3527306732.
^ http://www.prepchem.com/synthesis-of-2-5-hexanedione/ Primary: Systematic organic chemistry, by W. M. Cumming, 194, 1937.
^ U.S. patent 2,908,688
^ U.S. patent 4,140,793

[OS-1] Young, D. M.; Allen, C. F. H. (1936). "2,5-Dimethylpyrrole". Organic Syntheses. 16: 25. doi:10.15227/orgsyn.016.0025.

[2] Couri D, Milks M. "Toxicity and metabolism of the neurotoxic hexacarbons n-hexane, 2-hexanone, and 2,5-hexanedione" Annu. Rev. Pharmacol. Toxicol. 1982;22:145-66.

[tox-3] Stephen R Clough; Leyna Mulholland (2005), "Hexane", Encyclopedia of Toxicology, vol. 2 (2nd ed.), Elsevier, pp. 522–525

[ulltox-4] Wolfgang Dekant; Spiridon Vamvakas (2007). "Toxicology". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. p. 23. ISBN 978-3527306732.

[5] ttp://www.prepchem.com/synthesis-of-2-5-hexanedione/ Primary: Systematic organic chemistry, by W. M. Cumming, 194, 1937.

[6] U.S. patent 2,908,688

[7] U.S. patent 4,140,793

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