– Fmoc-9-aminononanoic acid is an alkane chian with terminal Fmoc-protected amine and carboxylic acid groups. The compound can be used as a PROTAC linker in the synthesis of PROTACs and and other conjugation applications. The Fmoc group can be deprotected under basic condition to obtain the free amine which can be used for further conjugations. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond.