N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB)
CAS21715-90-2
N-Hydroxy-5-norbornene-2,3-dicarboximide (HONB, CAS 21715-90-2) is an N-hydroxyimide additive used with carbodiimides such as DCC in peptide synthesis. It converts the activated carboxylic acid into an HONB active ester, which reduces racemization, prevents N-acylurea formation and gives peptides in good yield and purity. KingPharm supplies HONB for research and production with a batch-specific certificate of analysis.
- CAS No.
- 21715-90-2
- Formula
- C9H9NO3
- Mol. weight
- 179.17 g/mol
- Purity
- 99.0（HPLC）
- Appearance
- White to Off-white Powder
Product Description
N-Hydroxy-5-norbornene-2,3-dicarboximide (HONB) is a bicyclic N-hydroxyimide, C9H9NO3, supplied as a white to off-white crystalline powder. It is used mainly as a coupling additive in peptide synthesis and as the hydroxyl component for preparing active esters.
In a carbodiimide coupling, the O-acylisourea formed from the carboxylic acid and DCC is rapidly intercepted by HONB to give an HONB active ester. This ester is reactive enough to acylate the amine component but is less prone to oxazolone formation, so loss of stereochemical integrity is reduced, and the side reaction that leads to N-acylurea is suppressed.
Compared with N-hydroxysuccinimide (HOSu), HONB was reported to give lower racemization when used with DCC. Its rigid polycyclic structure is not susceptible to Lossen rearrangement, and it shows very little racemization in fragment condensation, where coupling at a C-terminal chiral residue is especially sensitive.
When sourcing HONB, check purity by HPLC or titration, melting point, water content and the endo/exo isomer description on the specification, since moisture and impurities affect active ester formation. KingPharm provides a batch-specific COA and specification with each lot.
Chemical Specifications
Identifiers
| CAS number | 21715-90-2 |
|---|---|
| Product name | N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) |
| Chinese name | N-羟基-5-降冰片烯-2,3-二甲酰亚胺 |
| IUPAC name | 4-hydroxy-4-azatricyclo[5.2.1.02,6]dec-8-ene-3,5-dione |
| Synonyms | N-Hydroxy-5-Norbornene-2.3-Dicarboxylicimide; N-Hydroxynorborn-5-Ene-2,3-Dicarboximide; Endo-N-Hydroxybicyclo[2.2.1]Hept-5-Ene-2,3-Dicarbo; N-Hydroxy-5-Norborchemicalbookene-2,3-Dicarboximide; N-Hydroxy-5-Norbornene-2,3-Dicarboximide；; Endo-N-Hydroxy-5-Norbornene-2; n-Hydroxy-5-Norbornene-Endo-2,3-Dicarboximiden-Hydroxybicyclo[2.2.1]Hept-5-Ene-2,3-Dicarboxylicacidimide |
| Chinese synonyms | N-羟基-5-降冰片烯-2,3-酰亚胺; N-羟基-5-降冰片烯-2,3-二羧酸酰亚胺; N-羟基-5-降冰片烯-2,3-二羧酰亚胺；; 内型-N-羟基-5-降冰片烯-2,3-二甲酰亚胺 |
| Molecular formula | C9H9NO3 |
| Molecular weight | 179.17 g/mol |
| EC number | 244-538-6 |
| MDL number | MFCD00167583 |
| PubChem CID | 89529 |
| InChIKey | ZUSSTQCWRDLYJA-UHFFFAOYSA-N |
| SMILES | C1C2C=CC1C3C2C(=O)N(C3=O)O |
Specification
| Test | Specification | Method |
|---|---|---|
| Melting Point | 164.0-170.0 | 熔点 |
| Appearance | White to Off-white Powder | 外观 |
| Purity | 99.0（HPLC） | 纯度（HPLC） |
| Water(KF) | 0.50% | 水分 |
Physical and chemical properties
| Appearance | White to Off-white Powder |
|---|---|
| Melting Point | 164.0-170.0 ( ℃ ) |
Applications
HONB is used wherever a carboxylic acid needs to be activated for amide bond formation with low racemization.
Carbodiimide peptide coupling
Added with DCC or other carbodiimides to form HONB active esters in situ, reducing racemization and N-acylurea by-products.
Fragment condensation
Used to couple protected peptide fragments, where activation at a C-terminal chiral residue requires low racemization.
Isolable active esters
Serves as the hydroxyl component for preparing HONB esters of amino acids and acids that can be isolated and purified before use.
Amide formation in medicinal chemistry
Used in DCC-mediated acylation of amines when building amide-linked intermediates for drug candidates.
Quality Documentation
The following documents can be provided for N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) to support technical evaluation and purchasing. Documents are issued for the specific grade and batch supplied.
-
Certificate of Analysis (COA) Batch-specific test results against the specification.
-
Product specification The release specification with test items, limits and methods.
Packaging, Storage & Transport
| Available pack sizes | 25 kg, 10 kg, 1 kg, 500 g, 100 g, 25 g |
|---|
Read the current safety data sheet before handling. Packaging can be adapted to the order quantity and destination.
Frequently Asked Questions
How does HONB compare with HOSu (NHS)?
Both form active esters with carbodiimides, but HONB was reported to give lower racemization with DCC and does not undergo Lossen rearrangement, which makes it suitable for racemization-sensitive couplings.
How is HONB typically used in a coupling?
HONB is usually added in about equimolar amount to the carboxylic acid together with the carbodiimide, then the amine component is added; reaction conditions should be optimized for each substrate.
How should HONB be stored?
Keep the container tightly closed in a cool, dry place away from light and moisture, since water affects active ester formation. Follow the storage conditions on the SDS.
What is the CAS number of N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB)?
The CAS Registry Number of N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) is 21715-90-2. N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) is also known as N-Hydroxy-5-Norbornene-2.3-Dicarboxylicimide; N-Hydroxynorborn-5-Ene-2,3-Dicarboximide; Endo-N-Hydroxybicyclo[2.2.1]Hept-5-Ene-2,3-Dicarbo.
What is the molecular formula and molecular weight of N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB)?
The molecular formula of N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) is C9H9NO3, and its molecular weight is 179.17 g/mol.
What is N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) used for?
HONB is used wherever a carboxylic acid needs to be activated for amide bond formation with low racemization.
Which quality documents are available for N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB)?
The following documents are available for N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB): Certificate of Analysis (COA); Product specification. Contact KingPharm to request the documents for a specific batch.
How can I request a quotation for N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB)?
Send an inquiry for N-Hydroxy-5-Norbornene-2,3-Dicarboxylic Acid Imide(HONB) (CAS 21715-90-2) with the required quantity, target specification, destination country and any documentation requirements. KingPharm will confirm availability, packaging, lead time and price.
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