H-Ser(tBu)-NH₂·HCl, also named O-tert-Butyl-L-serinamide hydrochloride, with molecular formula C₇H₁₇ClN₂O₂, molecular weight 196.68, CAS 323587-47-9, PubChem CID 87713751.It is a L-serine derivative with tert-butyl protecting group on side-chain hydroxyl and C-terminal amide. The tBu group is stable under Fmoc SPPS condition and can be cleaved by acid. It is widely used for synthesis of C-terminal amide peptides, branched peptides and therapeutic peptide candidates. Key