5-Methyl-2-hex-2-enoic Acid Methyl Ester-d3 is the isotope labelled analog of 5-Methyl-2-hex-2-enoic Acid Methyl Ester (M312075); the methyl ester derivative of 5-Methyl-2-hex-2-enoic Acid (M311960) which is used as a reagent in the synthesis of the anticonvulsant, Pregabalin (P704800).