2-Propenoic acid, 3-(3,4-dihydroxyphenyl)- 3,4-Dihydroxybenzeneacrylic acid 3,4-Dihydroxycinnamic acid 3-(3,4-Dihydroxy phenyl)-2-propenoic acid 3-(3,4-Dihydroxyphenyl)propenoic acid 331-39-5 4-(2'-Carboxyvinyl)-1,2-dihydroxybenzene 4-(2-Carboxyethenyl)-1,2-dihydroxybenzene CAFFEIC ACID Cinnamic acid, 3,4-dihydroxy- NSC57197