Kunshan Dingfa Chemical Co., Ltd.
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Address: Kunshan City High-tech Development Zone, North Road on the 5th 2 4F
The reaction of the carboxylic acid with the amine in the presence of the carbodiimide as a water loss agent is shown in the right figure.
The carboxylic acid 1 is first reacted with carbodiimide to form the intermediate O-acylisourea 2, similar to the introduction of the ester group-activated carboxylic acid. And then react with the amine to produce the target product amide 3 and urea 4.2 can be reacted with another molecular carboxylic acid to produce anhydride 5, acid anhydride and amine reaction also get amide 3. The byproduct of the reaction is mainly 2 rearrangements of N-acylurea 6. The use of low dielectric constant solvents (such as dichloromethane, chloroform) can reduce the formation of 6.