Related Experiment Video
Updated: May 16, 2026

Preparation of N-(2-alkoxyvinyl)sulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines
Published on: January 3, 2018
Rhodium-catalyzed cysteine modification with diazo reagents
Rituparna Kundu1, Zachary T Ball
1Department of Chemistry, MS 60, Rice University, 6100 Main Street, Houston, TX - 77005, USA.
A rhodium(II) complex enables selective cysteine modification using diazo reagents under mild conditions. The new method creates a more stable linkage in human plasma serum than maleimide reagents.
Area of Science:
- Organic Chemistry
- Bioconjugation Chemistry
- Catalysis
Background:
- Cysteine modification is crucial for bioconjugation and drug development.
- Existing methods like maleimide reagents face stability challenges in biological environments.
- Selective and robust cysteine functionalization remains an active area of research.
Purpose of the Study:
- To develop a novel catalytic method for cysteine modification.
- To investigate the stability of the resulting conjugate in human plasma serum.
- To compare the new method with existing maleimide-based approaches.
Main Methods:
- Utilizing a simple rhodium(II) complex as a catalyst.
- Employing diazo reagents for cysteine functionalization.
- Assessing the stability of the modified cysteine linkage in human plasma serum.
Main Results:
- The rhodium(II) catalyst demonstrated high selectivity for cysteine modification.
- The reaction proceeded efficiently under mild conditions.
- The linkage formed was significantly more stable in human plasma serum compared to maleimide-derived linkages.
Conclusions:
- A new, efficient, and selective method for cysteine modification using rhodium(II) catalysis has been established.
- The developed method offers enhanced stability of the cysteine linkage in biological fluids.
- This approach provides a valuable alternative to current bioconjugation strategies.
Related Concept Videos
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Diazonium Group Substitution: –OH and –H
Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo, or cyano...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
