(2E)-2,4-Pentadienoic Acid Ethyl Ester-d5 is the isotope labelled analog of (2E)-2,4-Pentadienoic Acid Ethyl Ester (P268355); the ethyl ester derivative of (2E)-2,4-Pentadienoic Acid (P268350) used as a reagent in the synthesis of the oxopolyene macrolide Dermostatin A.