5-Hydroxyferulic acid is an important hydroxycinnamic acid compound and a metabolite in the phenylpropanoid pathway. It acts as a precursor for the biosynthesis of sinapic acid and functions as a non-esterified substrate for COMT.
4-Chloro-α-cyanocinnamic acid (Cl-CCA), a phenylpropanoid derivative of cinnamic acid synthesized from phenylalanine by plants, exhibits a propensity for co-crystallization with a range of biomolecules, including peptides and nucleic acids.