11-Azido-3,6,9-trioxaundecanoic acid (97%)

Name: 11-Azido-3,6,9-trioxaundecanoic acid (97% purity) 

Molecular Formula: C8H15N3O5 

CAS#: 172531-37-2 

SMILES: OC(COCCOCCOCCN=[N+]=[N-])=O 

MDL#: MFCD16295189 

Catalog#: AMTGC502-AT19 

Molecular weight: 233.22 g/mol 

Other names: 

• 2-(2-(2-(2-azidoethoxy)ethoxy)ethoxy)acetic acid 

• (2-(2-(2-azidoethoxy)ethoxy)ethoxy)acetic acid 

• azido-dPEG3-acid 

Fields of Interest: PEGylating reagent, Organic Synthesis, Medicinal Chemistry 

Background & Applications: 

Background
11-Azido-3,6,9-trioxaundecanoic acid (CAS 172531-37-2) is a heterobifunctional azide-functionalized PEG linker based on a PEG3 backbone, featuring a terminal azide group and a carboxylic acid at the opposite end. The polyethylene glycol spacer provides hydrophilicity, flexibility, and compatibility with aqueous and biological environments. The azide functionality enables highly selective bioorthogonal click chemistry, while the carboxylic acid group allows straightforward activation (e.g., NHS ester formation) for coupling to amines and other nucleophiles. This dual-functional PEG linker is a valuable intermediate within a comprehensive portfolio of functionalized PEGs for controlled and site-specific conjugation. 

Applications
11-Azido-3,6,9-trioxaundecanoic acid is widely used in bioconjugation, drug delivery, and materials science applications requiring orthogonal reactivity and defined PEG spacing. Common uses include click-based attachment of PEG chains followed by amide bond formation with peptides, proteins, or small molecules, preparation of multifunctional linkers, and surface or nanoparticle modification. As part of a robust functionalized PEG product line, this azido-acid PEG supports modular design strategies in pharmaceutical research, diagnostics, biomaterials, and specialty chemical development. 

Appearance: Pale Yellow Liquid 

Purity: 97% 

Storage: 0-3 °C for long term storage 

Solubility: DCM 

Literature: 

1. Journal of the American Chemical Society, 2025, vol. 147, # 16, p. 13328 – 13344 
2. Journal of Drug Delivery Science and Technology, 2025, vol. 110, art. no. 107082