groups. It is found in all plants because it is a key intermediate in the biosynthesis of lignin , one of the principal sources of biomass . Read more... Edit at Wikipedia... Other names (2E)-3-(3,4-Dihydroxyphenyl)acrylic acid (IUPAC Name); 3-(3,4-Dihydroxyphenyl)-2-propenoic acid; (2E)-3-(3,4-dihydroxyphenyl)-2-propenoic acid; 3-(3,4-Dihydroxyphenyl)acrylic acid References Please add any relevant references here.