Fmoc-12-Ado-OH is the Fmoc-protected derivative of 12-aminododecanoic acid, a long-chain ω-amino acid used as a spacer or linker in peptide synthesis. It is particularly employed in solid-phase peptide synthesis (SPPS) to introduce a flexible 12-carbon alkyl chain, facilitating the connection of peptide segments or conjugation to surfaces, lipids, or other biomolecules. The Fmoc (9-fluorenylmethyloxycarbonyl) group protects the amino group during coupling reactions and is selectively removed under mild basic conditions (e.g., with piperidine in DMF), enabling stepwise assembly without interfering with other functional groups. This compound is essential for producing complex peptides, peptidomimetics, and bioconjugates in research, pharmaceutical development, and biotechnology applications.