Synthesis of all-trans-beta-carotene retinoids and derivatives labelled with14C

In this paper we report the synthesis of all-trans Retinoic acid, Retinal, Retinol specifically labelled with C-14 at position 7 and all-trans Beta-carotene labelled at positions 7 and 7', with more than 98% radiochemical purity. All products were obtained with about 15% overall yield from C-14 sodium cyanide.