Green CDI Reagent Replaces Toxic Phosgene in Peptide Synthesis

Researchers in peptide synthesis can now eliminate the risks associated with toxic phosgene through a safer, more efficient solution. High-purity carbonyl diimidazole (CDI) reagent, with a purity of ≥90.0% (proton NMR), offers a green alternative specifically designed for peptide bond formation.

CDI, chemically known as 1,1'-carbonyldiimidazole (C ₇ H ₆ N ₄ O, MW: 162.15), appears as a white or off-white solid with a melting point between 117-122°C. This crucial organic synthesis reagent activates carboxyl groups effectively to facilitate peptide bond formation while avoiding the hazards of phosgene.

The reagent-grade CDI meets stringent quality standards (grade 200), ensuring high purity and performance. Proton nuclear magnetic resonance analysis verifies the ≥90.0% purity, providing reliable results for research applications.

As a phosgene substitute, CDI aligns with green chemistry principles by offering a safer chemical design. Its adoption supports both efficient peptide synthesis and environmental sustainability.

• Coupling agent for synthesizing dipolar polyamides and polypeptides in nonlinear optics applications
• Preparation of β-ketosulfones and sulfoxides
• Synthesis of lead chelating agents
• Production of β-enamino acid derivatives

CDI primarily facilitates carbonyl group introduction (carbonylation) in organic molecules. As an activator, it reacts with carboxylic acids to form acyl imidazole intermediates that are more susceptible to nucleophilic attack. Common CDI-mediated reactions include:

• Esterification (carboxylic acid + alcohol → ester)
• Amidation (carboxylic acid + amine → amide)
• Peptide bond formation (amino acid coupling)
• Intramolecular cyclizations (e.g., lactone/lactam synthesis)

• Use in well-ventilated areas with protective gloves and eyewear
• Store in moisture-free environments
• Avoid contact with strong acids/bases
• Keep in cool, dry locations away from ignition sources

• DCC (dicyclohexylcarbodiimide)
• DIC (diisopropylcarbodiimide)
• EDC hydrochloride
• HATU/HBTU (uranium/phosphonium salts)

CDI offers distinct advantages including enhanced safety, high purity, broad applicability, and environmental benefits, making it a preferred choice for modern peptide synthesis.