fluoroamino acid phenylalanine derivative monofluorobenzenes non-proteinogenic alpha-amino acid 4-fluorophenylalanine p-Fluorophenylalanine DL-p-Fluorophenylalanine DL-Fluorophenylalanine CHEBI:88165 A phenylalanine derivative in which the hydrogen at position 4 on the benzene ring is replaced by a fluoro group. p-fluoro-DL-phenylalanine chebi_ontology CHEBI:84060