Synthesis of 15N‐5‐doxylstearic acid for improved EPR characterization of lipid motion in biomembranes

15N-5-Doxylstearic acid has been synthesized to improve EPR spectral characterization of the motional properties of the lipid in biological membranes. The EPR spectrum of the title compound displayed a 1.73 fold gain in sensitivity compared with the corresponding label substituted with the common isotope of nitrogen.