Synthesis of 13C‐labelled ω‐hydroxy carboxylic acids of the general formula HO213C‐(CH2)n‐CH2OH or HO2C‐(CH2)n‐13CH2OH (n = 12, 16, 20, 28)

13 C-labelled ω-hydroxy-carboxylic acids HO213 C-(CH2 )n -CH2 OH or HO2 C-(CH2 )n -13 CH2 OH (n = 12, 16, 20, 28) with 13 C labels selectively introduced either at the carboxy group or at the primary alcohol function at the end of the hydrocarbon chain have been synthesized. Different synthetic strategies had to be applied depending on the position of the label, the chain length of the respective synthetic target and due to economic considerations. 13 C labels in general were introduced by nucleophilic substitution of a suitable leaving group with labelled potassium cyanide and subsequent hydrolysis of the nitriles to produce the corresponding labelled carboxy functions, which may also be reduced to give the labelled primary alcohol group. All new compounds are characterized by GC/MS, IR and NMR methods as well as by elemental analysis.