Enzymatic synthesis of [3-14C]cinnamic acid

Convenient and efficient route of the synthesis of [3-C-14] cinnamic acid is reported. [1-C-14]Benzoic acid, prepared by carbonation of Grignard reagent with [C-14]carbon dioxide, was reduced to [1-C-14]benzyl alcohol. In the enzymatic step this alcohol was selectively oxidised to [1-C-14]benzaldehyde using enzyme YADH (Ec. 1.1.1.1) and immediately condensed with malonic acid. This combined chemical and enzymatic approach allows to obtain [3-C-14]cinnamic acid with radiochemical yield higher than 50% in respect to the starting alcohol.