9-Oxodecenoic acid

9-Oxodecenoic acid (9-oxo-2(E)-decenoic acid, also called 9-ODA) is an unsaturated ketocarboxylic or fatty acid and a pheromone secreted by the queen bee of the honeybee species Apis mellifera.^[1][2] It functions as a sex attractant that stimulates the olfactory receptors of male drones.^[3] Additionally, this acid plays a crucial role in regulating the colony's social structure; it inhibits the development of ovaries in worker bees, which are sterile females.^[3] However, its inhibitory effect on the worker bees' ovaries is only fully effective when combined with another pheromone, 9-hydroxydecenoic acid.^[4] When the queen bee is removed from the hive, the worker bees initiate the construction of new queen cells and the previously inhibited drones develop functional ovaries. The exact biological mechanisms through which 9-oxodecenoic acid and related substances influence these processes are not fully understood, but they are thought to affect the nervous system in some way.^[5]

9-Oxodecenoic acid is an important component of the pheromone of queen bees (center)

9-oxodecenoic acid

Names
Other names 9-oxo-2(E)-decenoic acid 9-ODA Queen substance
Identifiers
CAS Number	334-20-3
3D model (JSmol)	Interactive image
ChEBI	CHEBI:165439
ChemSpider	1362276
PubChem CID	1713086
UNII	618LR3X900
InChI InChI=1S/C10H16O3/c1-9(11)7-5-3-2-4-6-8-10(12)13/h6,8H,2-5,7H2,1H3,(H,12,13)/b8-6+ Key: INJRDZMWIAYEMM-SOFGYWHQSA-N
SMILES CC(=O)CCCCC/C=C/C(=O)O
Properties
Chemical formula	C10H16O3
Molar mass	184,23 g·mol−1
Appearance	transparent flakes
Melting point	54.5–55.5 °C (130.1–131.9 °F; 327.6–328.6 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Synthesis

9-Oxodecenoic acid can be synthesized starting from azelaic acid.^[6]

An efficient synthesis is possible starting from diethyl-3-oxoglutarate.^[7] This is alkylated by 6-bromo-1-hexene^[8] and magnesium ethanolate,^[9] then decarboxylated. The double bond is oxidized to the aldehyde with osmium tetroxide and sodium periodate in aqueous tert-butanol. The acid group is introduced by condensation with malonic acid.^[2]