alpha-iso-Methylionone

Description

α-Isomethylionone has a fine violet and orris-like odor. This substance may be synthesized by condensation of citral with methyl ethyl ketone controlling the ratio between the n- and iso-forms; the methyl pseudo-ionone obtained is then subjected to ring closure, using strong alkali and high temperature (thus favoring the formation of the normal α- and β-methylionones) or with quaternary ammonium base (thus favoring the formation of wo-forms); See also monographs of α- and β-ionone and methyl α-, β-, and γ-ionones.

Chemical properties

α-Isomethylionone has a fine violet and orris-like odor.

Preparation

By condensation of citral with methyl ethyl ketone controlling the ratio between the n- and iso-forms; the methyl pseudoionone obtained is then subjected to ring closure, using strong alkali and high temperature (thus favoring the formation of iso-forms); See also monographs of α-, β-, and γ-ionones.

Definition

ChEBI: 3-Methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one is a sesquiterpenoid.

Flammability and Explosibility

Not classified

Contact allergens

As a fragrance allergen, a-isomethylionone has to be mentioned by name in cosmetics within the EU.