Synthesis of (2,3-13C2) eruric acid

Article abstract of DOI:10.1002/jlcr.2580331003

The synthesis of (2,3-¹³C₂) erucic acid, for use in metabolic studies, is reported. The synthesis employs a repeated 3 step reaction sequence using ¹³C labeled triethylphosphonoacetate to extend C(18:1), oleyl alcohol, by 4 carbons. The starting alcohol is first oxidized with PCC and the resulting aldehyde is condensed with triethyl(1-¹³C)phosphonoacetate. The product, an α,β unsaturated ester, is reduced with (Ph₃PCuH)₆ to ethyl eicosenoate. Reduction with LAH gives eicosenoyl alcohol. A repetition of the reaction sequence using triethyl(2-¹³C) phosphonoacetate results in ethyl(2,3-¹³C₂)erucate. The (2,3-¹³C₂) erucic acid, obtianed by hydrolysis with alcoholic KOH, gave ¹³C NMR signals of δ 24.6 and 34.1 ppm for C-3 and C-2 respectively with a J = 34.9 Hz. The overall yield was 5.5%.