6-Chloro D-Tryptophan is used primarily as a chiral building block in the synthesis of pharmaceutical compounds, especially those targeting the central nervous system. It serves as an intermediate in the production of selective serotonin reuptake inhibitors (SSRIs) and other neuroactive agents. Due to its structural similarity to natural tryptophan, it can be incorporated into peptide-based drugs to modulate metabolic stability and receptor selectivity. It is also employed in research settings to study enzyme mechanisms involving tryptophan hydroxylase and other aromatic amino acid metabolizing enzymes. Its D-configuration provides resistance to degradation by many proteolytic enzymes, making it valuable in designing metabolically stable therapeutics.