Synthesis of deuterated β-carotene

Routine studies of the metabolism of carotenoids in humans require carotenoids labeled with nonradioactive isotopes. Appropriately labeled compounds should be symmetrically labeled and should contain sufficient nonlabile isotope, such that the interfering ions from naturally occurring carbon isotopes do not appreciably interfere with the analysis. This chapter describes a procedure for the preparation of an appropriate deuterium (D)-labeled analog of β-carotene. It also discusses β -ionone and triethyl phosphonoacetate can be purified by distillation under vacuum. Solvents are anhydrous reagent grade. Tetrahydrofuran (THF) is distilled from lithium aluminum hydride under an inert atmosphere prior to use. Thin-layer chromatography can be performed on silica gel plates containing fluorescent indicators to monitor reactions. Visualization can be performed by illumination with an ultraviolet (UV) lamp.