(2E)-3-(Phenyl-2,3,4,5,6-d5)-2-propenoic-2,3-d2 Acid is an isotope labelled compound of trans-Cinnamic Acid (P336185), used in the synthesis of amides and esters through coupling reactions involving carboxylic acids and amines. Also used in the N-methylation of amides and O-methylation of carboxylic acids.