carbodiimideactivated

Carbodiimide activated refers to a chemical functional group or molecule that has undergone a reaction with a carbodiimide coupling agent. Carbodiimides are a class of organic compounds with the general formula R-N=C=N-R', where R and R' are organic substituents. They are commonly used as dehydrating agents in organic synthesis, particularly for the formation of amide and ester bonds.

When a carbodiimide reacts with a carboxylic acid, it forms an O-acylisourea intermediate. This intermediate is highly reactive and can be readily attacked by a nucleophile, such as an amine or an alcohol, to form the desired amide or ester, respectively. The carbodiimide itself is converted into a urea byproduct. The activation process essentially converts a relatively unreactive carboxylic acid into a more electrophilic species that is susceptible to nucleophilic attack.

Commonly used carbodiimide coupling agents include dicyclohexylcarbodiimide (DCC) and N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC). DCC is often used in laboratory settings, but its urea byproduct can be difficult to remove. EDC is water-soluble and its urea byproduct is also water-soluble, making it more convenient for reactions in aqueous media or for purification.

The carbodiimide activation strategy is widely employed in peptide synthesis, where it facilitates the formation of peptide bonds between amino acids. It is also used in the synthesis of esters, anhydrides, and other functional groups. The reaction conditions and choice of carbodiimide can be optimized to achieve high yields and minimize side reactions.