123333-53-9

N-Hydroxybenzotriazole Hydrate (HOBT)

1-Hydroxybenzotriazole monohydrate (HOBt hydrate), with the CAS number 123333-53-9, is a white crystalline solid primarily utilized as a coupling additive in pharmaceutical R&D, industrial peptide manufacturing, and organic synthesis. It is highly favored for suppressing racemization and improving the efficiency of peptide bond formation, typically paired with carbodiimide reagents (like DCC, EDC, DIC).

Chemical Properties

  • Molecular Formula: 𝐶6𝐻5𝑁3𝑂⋅𝐻2𝑂
  • Molecular Weight: 155.14 g/mol (Monohydrate)
  • Appearance: White crystalline solid/powder
  • Melting Point: 153.0 – 160.0 °C (decomposes)
  • Solubility: Soluble in DMF, DMSO, and methanol.
  • Water Content: Usually contains ~11.7% to 14% water (roughly 1:1 molar ratio).
  • Stability: Stable under recommended storage. Anhydrous HOBt is explosive, which is why the monohydrate form (wetted with ~11.7–20% water) is preferred for safety.
  • Storage: Cool, dry place; light-sensitive.

 

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Synonyms

  • HOBt ⋅ H2O
  • 1-Hydroxybenzotriazole hydrate
  • 1-Hydroxy-1,2,3-benzotriazole monohydrate
  • 1-Hydroxybenzotriazole (wetted with not less than 20 wt% water)

Uses and Applications

  1. Peptide Synthesis: Acts as an additive in carbodiimide-mediated coupling reactions (Solid-Phase Peptide Synthesis – SPPS; Solution-Phase Peptide Synthesis) to prevent epimerization/racemization.
  2. Amide Bond Formation: Facilitates amide formation by forming stable, activated OBt-esters from carboxylic acids.
  3. Pharmaceutical Intermediate: Key component in the synthesis of APIs (Active Pharmaceutical Ingredients) such as Captopril, Ritonavir, and Sitagliptin.
  4. Organic Transformations: Used in the synthesis of heterocyclic compounds, such as oxadiazoles via cyclocondensation.
  5. Polymer Chemistry: Used to form medium-ring lactams.

Safety and Handling

  • Explosive Risk: Anhydrous HOBt is a hazardous, explosive material. The hydrated form (123333-53-9) is used specifically to mitigate this, but it must still be handled with care and kept away from heat and friction.
  • Hazardous Identification: Flammable solid (Category 2).
  • Precautions: Keep away from heat, sparks, and open flames. Use protective clothing.

 

 

What is N-Hydroxybenzotriazole Hydrate (HOBt)?
N-Hydroxybenzotriazole Hydrate (HOBt) is a chemical compound commonly used in peptide synthesis to improve coupling efficiency and reduce unwanted side reactions.
What are the main applications of HOBt?
HOBt is widely used in pharmaceutical research, peptide manufacturing, organic synthesis, and chemical laboratories.
Why is HOBt used in peptide synthesis?
It helps activate carboxyl groups, increases reaction yields, and minimizes racemization during peptide bond formation.
How should N-Hydroxybenzotriazole Hydrate be stored?
It should be stored in a cool, dry, and well-ventilated area, away from heat, moisture, and incompatible substances.
Is N-Hydroxybenzotriazole Hydrate safe to handle?
HOBt should be handled with proper safety precautions, including the use of protective gloves, goggles, and appropriate laboratory safety practices.

FAQs

What is N-Hydroxybenzotriazole Hydrate (HOBt)?
N-Hydroxybenzotriazole Hydrate (HOBt) is a chemical compound commonly used in peptide synthesis to improve coupling efficiency and reduce unwanted side reactions.
What are the main applications of HOBt?
HOBt is widely used in pharmaceutical research, peptide manufacturing, organic synthesis, and chemical laboratories.
Why is HOBt used in peptide synthesis?
It helps activate carboxyl groups, increases reaction yields, and minimizes racemization during peptide bond formation.
How should N-Hydroxybenzotriazole Hydrate be stored?
It should be stored in a cool, dry, and well-ventilated area, away from heat, moisture, and incompatible substances.
Is N-Hydroxybenzotriazole Hydrate safe to handle?
HOBt should be handled with proper safety precautions, including the use of protective gloves, goggles, and appropriate laboratory safety practices.

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