Synthesis of ¹³C-labelled cutin and suberin monomeric dicarboxylic acids of the general formula HO₂¹³C-(CH₂)ₙ-¹³CO₂H (n = 10, 12, 14, 16, 18, 20, 22, 24, 26, 28)

¹³C-labeled dicarboxylic acids HO₂¹³C-(CH₂)_n-¹³CO₂H (n = 10, 12, 14, 16, 18, 20, 22, 24, 26, 28) have been synthesized as internal standards for LC-MS and GC-MS analysis of cutin and suberin monomer degradation by soil-based microorganisms. Different synthetic strategies had to be applied depending on the chain length of the respective synthetic target and because of economic considerations. ¹³C-labels were introduced by nucleophilic substitution of a suitable leaving group with labelled potassium cyanide and subsequent hydrolysis of the nitriles to produce the corresponding dicarboxylic acids. All new compounds are characterized by GC/MS, IR, and NMR methods as well as by elemental analysis.