Beta-ionone

Ionones

Names
IUPAC names α: (3E)-4-(2,6,6-Trimethylcyclohex-2-en-1-yl)but-3-en-2-one β: (3E)-4-(2,6,6-Trimethylcyclohex-1-en-1-yl)but-3-en-2-one γ: (3E)-4-(2,2-Dimethyl-6-methylenecyclohexyl)but-3-en-2-one
Other names Cyclocitrylideneacetone, irisone, jonon
Identifiers
CAS Number	127-41-3 α N 79-77-6 β N 79-76-5 γ N
3D model (Jmol)	Interactive image
ChEBI	CHEBI:49250 Y
ChemSpider	4516050 Y
PubChem	5363741
UNII	QP734LIN1K Y
InChI InChI=1S/C13H20O/c1-10-6-5-9-13(3,4)12(10)8-7-11(2)14/h7-8,12H,1,5-6,9H2,2-4H3/b8-7+ Y Key: SFEOKXHPFMOVRM-BQYQJAHWSA-N Y InChI=1/C13H20O/c1-10-6-5-9-13(3,4)12(10)8-7-11(2)14/h7-8,12H,1,5-6,9H2,2-4H3/b8-7+ Key: SFEOKXHPFMOVRM-BQYQJAHWBW
SMILES O=C(\C=C\C1\C(=C)CCCC1(C)C)C
Properties
Chemical formula	C13H20O
Molar mass	192.30 g/mol
Density	α: 0.933 g/cm3 β: 0.945 g/cm3
Melting point	β: −49 °C (−56 °F; 224 K)
Boiling point	β: 126 to 128 °C (259 to 262 °F; 399 to 401 K) at 12 mmHg
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

The ionones are a series of closely related chemical substances that are part of a group of compounds known as rose ketones, which also includes damascones and damascenones. Ionones are aroma compounds found in a variety of essential oils, including rose oil. β-Ionone is a significant contributor to the aroma of roses, despite its relatively low concentration, and is an important fragrance chemical used in perfumery. The ionones are derived from the degradation of carotenoids.

The combination of α-ionone and β-ionone is characteristic of the scent of violets and used with other components in perfumery and flavouring to recreate their scent.

The carotenes α-carotene, β-carotene, γ-carotene, and the xanthophyll, and β-cryptoxanthin, can all be metabolized to β-ionone, and thus have vitamin A activity because they can be converted by plant-eating animals to retinol and retinal. Carotenoids that do not contain the β-ionone moiety cannot be converted to retinol, and thus have no vitamin A activity.

Carotenoids are the precursors of important fragrance compounds in several flowers. For example, a 2010 study of ionones in Osmanthus fragrans Lour. var. aurantiacus determined its essential oil contained the highest diversity of carotenoid-derived volatiles among the flowering plants investigated. A cDNA encoding a carotenoid cleavage enzyme, OfCCD1, was identified from transcripts isolated from flowers of O. fragrans Lour. The recombinant enzymes cleaved carotenes to produce α-ionone and β-ionone in in vitro assays.