1-Hydroxybenzotriazole hydrate

wetted with not less than 14 wt. % water, 98%

HOBt Hydrate
Empirical Formula (Hill Notation):
C6H5N3O · xH2O
CAS Number:
Molecular Weight:
135.12 (anhydrous basis)
Beilstein/REAXYS Number:
EC Number:
PubChem Substance ID:

Quality Level




synthesis grade

reaction suitability

reaction type: Addition Reactions


peptide synthesis: suitable


155-158 °C (lit.)

SMILES string




InChI key


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25, 100, 250 g in glass bottle


Additive used in oligonucleotide couplings and in racemization-free peptide couplings.


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Signal Word


Hazard Statements

Supp Hazards



UN3474 - class 4.1 - PG 1 - 1-Hydroxybenzotriazole, monohydrate

WGK Germany


Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Certificate of Analysis

Certificate of Origin

  1. Which document(s) contains shelf-life or expiration date information for a given product?

    If available for a given product, the recommended re-test date or the expiration date can be found on the Certificate of Analysis.

  2. How do I get lot-specific information or a Certificate of Analysis?

    The lot specific COA document can be found by entering the lot number above under the "Documents" section.

  3. How do I find price and availability?

    There are several ways to find pricing and availability for our products. Once you log onto our website, you will find the price and availability displayed on the product detail page. You can contact any of our Customer Sales and Service offices to receive a quote.  USA customers:  1-800-325-3010 or view local office numbers.

  4. What is the Department of Transportation shipping information for this product?

    Transportation information can be found in Section 14 of the product's (M)SDS.To access the shipping information for this material, use the link on the product detail page for the product. 

  5. Why is Product 157260, Hydroxybenzotriazole hydrate wet?

    Hydroxybenzotriazole hydrate is a solid that is explosive when dry. Our specification for this product is >14% water.

  6. Can Product 157260, Hydroxybenzotriazole hydrate, be dried?

    Drying hydroxybenzotriazole hydrate should not be attempted because of its explosive nature.

  7. How is Product 157260, Hydroxybenzotriazole hydrate, shipped?

    Hydroxybenzotriazole hydrate can not travel be sea or air. It is typically shipped by truck.

  8. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

  9. My question is not addressed here, how can I contact Technical Service for assistance?

    Ask a Scientist here.

Tetrahedron Letters, 35, 3315-3315 (1994)
Tetrahedron Letters, 34, 6383-6383 (1993)
T Katoh et al.
International journal of peptide and protein research, 42(3), 264-269 (1993-09-01)
3-Dimethylphosphinothioyl-2(3H)-oxazolone (MPTO) was synthesized, and its ability to effect racemization-free couplings and cyclization of a peptide and its C-terminal epimer was examined. MPTO showed good reactivity in aprotic polar solvents such as N,N-dimethylformamide (DMF) and N-methylpyrrolidone. In reactivity MPTO resembles...
Synlett, 733-733 (1993)
Donna Wesolowski et al.
Proceedings of the National Academy of Sciences of the United States of America, 108(40), 16582-16587 (2011-09-29)
Basic peptides covalently linked to nucleic acids, or chemically modified nucleic acids, enable the insertion of such a conjugate into bacteria grown in liquid medium and mammalian cells in tissue culture. A unique peptide, derived from human T cells, has...

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