Active esters/additives
Active esters are reactive intermediates, such as NHS esters and chloroformates, used to activate a carboxylic acid during synthesis, and are a core tool in bioconjugation and peptide chemistry. These standards support PEGylation, linker synthesis for antibody-drug conjugates, and general amide bond formation. Because active esters are moisture-sensitive and can degrade over time, sourcing a verified, freshly characterized standard with a certificate of analysis helps avoid failed or inconsistent coupling reactions. This matters for labs working on antibody-drug conjugates and diagnostic probe synthesis.
Showing all 6 results
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4-Methyl-5-nitrocatechol
CAS Number: 68906-21-8
Molecular Formula: C7 H7 N O4
Catalogue Number: RCLS2L163360
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4-Nitrophenyl Chloroformate >90%
CAS Number: 7693-46-1
Molecular Formula: C7 H4 Cl N O4
Catalogue Number: RCLS2L168823
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5-Hydroxymethyl-2-furoylglycine
CAS Number: 38716-68-6
Molecular Formula: C8 H9 N O5
Catalogue Number: RCLS2L153296
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N,N?-Disuccinimidyl Carbonate
CAS Number: 74124-79-1
Molecular Formula: C9 H8 N2 O7
Catalogue Number: RCLS2L137848
Reliable Active Ester Standards for Bioconjugation and Synthesis Work
Accurate active ester and additive standards matter wherever a coupling reaction, bioconjugation step, or linker synthesis is involved. Because these compounds are reactive and moisture-sensitive by nature, starting with degraded or uncertified material often shows up later as a failed or low-yielding reaction, costing time and materials.
Clinivex supplies a focused range of active ester and additive standards, each backed by a certificate of analysis and stored and handled to preserve reactivity. Our technical team is available to advise on suitable alternatives or handling recommendations for moisture-sensitive compounds.
As an ISO 9001:2015 and GMP certified supplier working with laboratories and pharmaceutical companies across the USA and Canada, we focus on getting reliable material to your bench with the documentation your synthesis work requires. We take extra care in how these compounds are packaged and shipped, since preserving reactivity from the moment they leave our facility to the moment they reach your bench directly affects reaction success.
Many synthesis routes built around these active esters begin with a starting material from the broader building blocks category. Active esters are also a core tool in the kind of work found in pharmaceutical and biotech research, particularly antibody-drug conjugate development and diagnostic probe synthesis.
Contact our team to request a quote or check availability for a specific active ester or additive standard.
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Frequently Asked Questions
An active ester is a reactive intermediate that activates a carboxylic acid, making it easier to form an amide bond, which is a common step in peptide synthesis and bioconjugation chemistry.
Most active esters react readily with moisture, so improper storage can cause them to degrade before use, which is why sourcing freshly characterized, certified material matters.
NHS esters are among the most widely used active esters for reacting with amine groups in bioconjugation, valued for a good balance of reactivity and selectivity compared to some other active ester types.
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