Fmoc-5-Chloro-L-tryptophan is primarily used in peptide synthesis, particularly in solid-phase peptide synthesis (SPPS). It serves as a protected amino acid derivative, where the Fmoc group ensures selective deprotection during the synthesis process. The compound is valuable for incorporating 5-chloro-L-tryptophan residues into peptides, which can be crucial for studying biological activity, receptor binding, or enzyme interactions. Its application is significant in pharmaceutical research for developing peptide-based drugs, as well as in biochemical studies to explore protein structure and function. Additionally, it is utilized in the synthesis of modified peptides for probing specific biological pathways or designing inhibitors.