HOAt - Coupling Additive for Peptide Synthesis

Setting 

Catalog No.

A7024

peptide coupling agent

• Background
• Product Citation
• Chemical Properties
• Quality Control
• User Guide

Background

HOAt (1-Hydroxy-7-azabenzotriazole; CAS 39968-33-7) is a peptide coupling reagent frequently employed in peptide synthesis for the activation of carboxylic groups. Structurally, HOAt serves as an activating additive that forms reactive intermediates facilitating amide bond formation while mitigating side reactions such as racemization. As reported in experimental peptide coupling studies, combining HOAt with diisopropylcarbodiimide (DIC) promotes coupling reactions with improved retention of stereochemical integrity relative to traditional coupling systems utilizing other benzotriazole derivatives. HOAt is thus commonly used both in segment coupling and stepwise solid-phase peptide assembly methodologies aimed at synthesizing peptides requiring minimal epimerization.

Reference:
Carpino L A, El-Faham A.  The diisopropylcarbodiimide/1-hydroxy-7-azabenzotriazole system: segment coupling and stepwise peptide assembly[J]. Tetrahedron, 1999, 55(22): 6813-6830.

Product Citation

• 1. Anjali Dixit, Brian M Paegel, et al. "Solid - phase DNA - encoded library synthesis: a master builder's instructions." Nat Protoc. 2025 May 22 PMID: 40404924
• 2. Kacy L Black, Ian K Webb, et al. "Development of Electrostatic-to-Covalent Gas Phase Cross-linkers for Protein Structure Measurements by Mass Spectrometry." J Am Soc Mass Spectrom. 2025 Mar 5;36(3):483-494. PMID: 39936477

Chemical Properties

Physical Appearance	A solid
Storage	Desiccate at -20°C
M.Wt	136.11
Cas No.	39968-33-7
Formula	C5H4N4O
Solubility	≥3.62 mg/mL in H2O with ultrasonic; ≥6.81 mg/mL in DMSO; ≥9.29 mg/mL in EtOH with ultrasonic
Chemical Name	3-hydroxytriazolo[4,5-b]pyridine
Canonical SMILES	O[n]1nnc2cccnc12
Shipping Condition	Small Molecules with Blue Ice, Modified Nucleotides with Dry Ice.
General tips	We do not recommend long-term storage for the solution, please use it up soon.

Quality Control

Chemical structure

User Guide

General User Guide for APExBIO Small Molecule Compounds