Enzymatic Synthesis of [3-14C]Cinnamic Acid

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