H-Ser(tBu)-OtBu, with CAS number 48067-24-9, is a protected serine derivative. Its chemical name is N-(tert-Butoxycarbonyl)-O-tert-butyl-L-serine tert-butyl ester. This compound features tert-butyl protecting groups on both the amino (Boc), carboxyl (OtBu), and side-chain hydroxyl (O-tBu) functionalities, rendering it a fully protected serine building block. This derivative is a crucial intermediate in solid-phase peptide synthesis (SPPS) and solution-phase peptide chemistry. The tert-butyl protecting groups are stable under the acidic conditions typically used for Boc-deprotection but can be cleaved under strong acidic conditions (e.g., with trifluoroacetic acid) in the final deprotection step. Its primary application is in the research and development of therapeutic peptides, where it is used to incorporate serine residues while preventing unwanted side reactions during the elongation of the peptide chain. As a high-purity, protected amino acid, it is a staple reagent in bioconjugation, peptide library construction, and the synthesis of peptide-based drugs and bioactive compounds. It is handled as a fine chemical under standard laboratory safety protocols for organic compounds.