(3E,5E,7E)-9-[(3E)-2,4,4-Trimethyl-1-cyclohexen-3-ylidene]-3,7-dimethylnona-3,5,7-trien-1-ol

A degradation product of Vitamin A (R252000). Vitamin A impurity.

Retro-vitamin A is obtained by treatment of retinol in the presence of concentrated hydrobromic acid. In the case of retinoic acid and retinal, reisomerization is possible after conversion to appropriate derivatives such as the acid chloride or the hydroquinone adduct.