2,5-Undecanedione

2,5-Undecanedione
	; Structural formula of 2,5-Undecanedione
Names
	Other names Undecan-2,5-dione
Identifiers
CAS Number	7018-92-0 ;
3D model (JSmol)	Interactive image;
ChemSpider	73524;
ECHA InfoCard	100.027.544
EC Number	230-297-4;
PubChem CID	81489;
UNII	F8UB9Q3X7Y;
CompTox Dashboard (EPA)	DTXSID50220458 ;
	InChI InChI=1S/C11H20O2/c1-3-4-5-6-7-11(13)9-8-10(2)12/h3-9H2,1-2H3 Key: ZHMCDZHVHDFSHO-UHFFFAOYSA-N;
	SMILES CCCCCCC(=O)CCC(=O)C;
Properties
Chemical formula	C11H20O2
Molar mass	184.279 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

2,5-Undecanedione is a γ-diketone in which the two carbonyl groups are separated by two methylene groups.

Synthesis

Heinz Hunsdiecker described the synthesis of 2,5-undecanedione from 5-methylfurfural in 1942. 5-Methylfurfural 1 is first reacted with methyl propyl ketone 2 in an aldol condensation reaction to form an α,β-unsaturated carbonyl compound 3. The double bond of the side chain condensation product is reduced with sodium amalgam. The intermediate 4 is then converted to 2-methyl-5-hexylfuran 5 in a Wolff-Kishner reduction using hydrazine. An acid-catalyzed reaction at 120 °C (248 °F) cleaves the furan ring, producing 2,5-undecanedione 6.^[1]

An alternative route of synthesis starts with heptanal 1. First, the carbonyl group is protected with 1,3-propanedithiol 2, producing a dithiane 3. The dithiane is deprotonated using n-Butyllithium in tetrahydrofuran, and alkylated using 1,3-dichloro-2-butene 4 to give the intermediate 5. Hydrolysis of the dithioacetal protecting group with concentrated sulfuric acid yields 2,5-undecanedione 6, which can be worked up and purified using Girard's reagent T^[2] in methanol.^[3]

2,5-Undecanedione is used in the Hunsdiecker condensation [de], a reaction developed by Heinz Hunsdiecker in 1942 to produce cyclopentenones from γ-ketones, in sodium hydroxide solution to produce the fragrance dihydrojasmone:^[1]

^ ^a ^b Heinz Hunsdiecker (1942-05-06), "Über das Verhalten der γ-Diketone, I. Mitteilung", Berichte der Deutschen Chemischen Gesellschaft, vol. 75, no. 5, pp. 447–454, doi:10.1002/cber.19420750502
^ PubChem. "Girard's reagent T". pubchem.ncbi.nlm.nih.gov. Retrieved 2024-11-05.
^ Ho, Tse-Lok; Ho, Honor C.; Wong, C. M. (1973-01-15). "A Synthetic Route to Dihydrojasmone; Sulfuric Acid as Dethioacetalization Agent". Canadian Journal of Chemistry. 51 (2): 153–155. doi:10.1139/v73-023. ISSN 0008-4042.