HOAt | Cas# 39968-33-7 | Peptide Coupling Reagents

HOAt is a coupling reagent that promotes peptide bond formation between carboxylic acids and amines by first reacting with the acid to generate an activated intermediate, which then reacts with the amine to form the amide.

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Cas No.: 39968-33-7

Sample solution is provided at 25 µL, 10mM.



GlpBio Products Cited In Reputable Papers

Description of HOAt

HOAt is a coupling reagent that promotes peptide bond formation between carboxylic acids and amines by first reacting with the acid to generate an activated intermediate, which then reacts with the amine to form the amide[1]. The nitrogen at the 7-position in HOAt provides a classic neighboring group effect that can both increase the reactivity and reduce racemization[2]. In combination with 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide (EDC) and N,N′-diisopropylethylamine (DIPEA), HOAt can be employed to promote the amide-bond-forming step between amino-modified DNA and carboxylic acids during the construction of DNA-encoded combinatorial libraries[3]. HOAt functions as a non-mutagenic pharmaceutical reagent, a common drug impurity and a metal-binding pharmacophore, while also exhibiting pronounced corrosion-inhibition activity toward mild steel[4-5]. HOAt can be used with HOBt in a relay fashion to catalyze the route from α-reducible aldehydes and amines to α-reduced amides[6].

References:
[1] Nicolette J, Neft RE, Vanosdol J, Murray J. Peptide bond-forming reagents HOAt and HATU are not mutagenic in the bacterial reverse mutation test. Environ Mol Mutagen. 2016 Apr;57(3):236-40. doi: 10.1002/em.21997.
[2] Subirós-Funosas R, Prohens R, Barbas R, El-Faham A, Albericio F. Oxyma: an efficient additive for peptide synthesis to replace the benzotriazole-based HOBt and HOAt with a lower risk of explosion. Chemistry. 2009 Sep 21;15(37):9394-403.
[3] Li Y, Gabriele E, Samain F, et al. Optimized Reaction Conditions for Amide Bond Formation in DNA-Encoded Combinatorial Libraries. ACS Comb Sci. 2016;18(8):438-443.
[4] Liu X, Yan W, Yang G, et al. 1-hydroxy-7-azabenzotriazole-cinnamic esters as anti-Toxoplasma gondii agents. Nat Prod Res. Published online May 8, 2025.
[5] Gao L, Peng S, Gong Z, Chen J. A combination of experiment and theoretical methods to study the novel and low-cost corrosion inhibitor 1-hydroxy-7-azabenzotriazole for mild steel in 1 M sulfuric acid. RSC Adv. 2018;8(67):38506-38516.
[6] Vora HU, Rovis T. Nucleophilic carbene and HOAt relay catalysis in an amide bond coupling: an orthogonal peptide bond forming reaction. J Am Chem Soc. 2007 Nov 14;129(45):13796-7. doi: 10.1021/ja0764052.

Chemical Properties of HOAt

Cas No.	39968-33-7	SDF
Chemical Name	3-hydroxytriazolo[4,5-b]pyridine
Canonical SMILES	C1=CC2=C(N=C1)N(N=N2)O
Formula	C5H4N4O	M.Wt	136.11
Solubility	≥ 6.8mg/mL in DMSO, ≥ 9.29 mg/mL in EtOH with ultrasonic, ≥ 3.62 mg/mL in Water with ultrasonic	Storage	Desiccate at -20°C
General tips	Please select the appropriate solvent to prepare the stock solution according to the solubility of the product in different solvents; once the solution is prepared, please store it in separate packages to avoid product failure caused by repeated freezing and thawing.Storage method and period of the stock solution: When stored at -80°C, please use it within 6 months; when stored at -20°C, please use it within 1 month. To increase solubility, heat the tube to 37°C and then oscillate in an ultrasonic bath for some time.
Shipping Condition	Evaluation sample solution: shipped with blue ice. All other sizes available: with RT, or with Blue Ice upon request.

Complete Stock Solution Preparation Table of HOAt

Prepare stock solution
	1 mg	5 mg	10 mg
1 mM	7.347 mL	36.735 mL	73.47 mL
5 mM	1.4694 mL	7.347 mL	14.694 mL
10 mM	734.7 μL	3.6735 mL	7.347 mL

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