Boc-5-aminopentanoic NHS ester

Boc-5-aminopentanoic NHS ester is an activated amino-acid linker designed for efficient coupling in PROTAC assembly, enabling attachment of amine-bearing ligands to NHS-activated electrophiles under mild conditions. Its Boc-protected amino functionality provides a convenient handle for sequential synthesis, while the NHS ester supports rapid formation of stable amide bonds. The linker’s design supports modular construction of targeted protein degraders, and the details below describe its structure and practical reactivity for experimental workflows.

Structure: The molecule contains an N-hydroxysuccinimide ester that is conjugated to a carboxylate, along with a Boc-protected amine and a flexible aliphatic pentyl spacer. It features ester and carbamate functionalities, plus an amide-forming carboxylate equivalent, offering controlled reactivity and solubility suitable for linker chemistry.

Reactivity: The NHS ester reacts with primary amines to form amide bonds via nucleophilic acyl substitution, typically in aqueous-organic buffers that maintain the electrophile’s stability. Suitable conditions include controlled pH to favor amine nucleophilicity while limiting hydrolysis, with common solvents such as DMF or DMSO mixed with buffer. No special catalysts are generally required; rapid coupling and careful exclusion of excess water improve conversion.