H-γ-Abu-OtBu.HCl is the hydrochloride salt of the tert-butyl ester of γ-aminobutyric acid (GABA), a key building block in peptide synthesis. It features a free amino group for coupling to the growing peptide chain and a tert-butyl (OtBu) protecting group on the carboxylic acid, which prevents unwanted reactions and allows selective deprotection at later stages. This compound is essential for synthesizing peptides and peptidomimetics that incorporate GABA units, particularly in pharmaceutical applications targeting the central nervous system, such as GABA receptor agonists or antagonists for neurological and muscular disorders. It is also utilized in organic synthesis for constructing complex molecules requiring precise functional group manipulation.