2S,4R)-4-Hydroxyproline, or L-hydroxyproline (C5H9O3N), is a common non-proteinogenic amino acid, abbreviated as Hyp, e.g., in Protein Data Bank.
Trans-4-Hydroxy-L-proline is a versatile reagent for the synthesis of neuroexcitatory kainoids and antifungal echinocandins. Also employed in the synthesis of chiral ligands for enantioselective ethylation of aldehydes. trans-4-Hydroxy-L-proline is a natural constituent of animal structural proteins such as collagen and elastin. A versatile reagent for the synthesis of neuroexcitatory kainoids and antifungal echinocandins