Boc-3-(2-Thienyl)-L-alanine is a protected non-proteinogenic amino acid derivative. Its structure features an L-alanine backbone with a 2-thienyl substituent at the β-position and a tert-butoxycarbonyl (Boc) group protecting the α-amino functionality. This configuration makes it a chiral building block containing both an aromatic heterocycle (thiophene) and a protected amine. This compound is primarily employed as a key intermediate in the research and development of peptide-based pharmaceuticals and bioactive molecules. The thiophene ring can impart specific electronic and hydrophobic properties to the final peptide, potentially influencing its binding affinity and metabolic stability. It is used to introduce the unnatural amino acid residue 3-(2-thienyl)-L-alanine into peptide sequences during solid-phase or solution-phase peptide synthesis, following Boc-deprotection protocols. As a specialty amino acid derivative, it finds application in medicinal chemistry for creating peptide mimetics and investigating structure-activity relationships (SAR). Its use is confined to laboratory-scale synthesis for research purposes.