Uploaded February 2023 | Updated September 2026, 2 weeks ago
The mechanism for the formation of a diazetidine by-product that is produced in the DCC peptide coupling reaction where HOBt is included as an additive. In order to reduce the epimerization level when using carbodiimides as coupling reagent, it has been shown that when 1-hydroxy-1H-benzotriazole (HOBt) was included as an additive, yields increased and epimerization levels decreased. However, when using these two reagents together, this side reaction can occur yielding the diazetidine by-product.
Music: Whisper – Mokka
The mechanism for the formation of a diazetidine by-product that is produced in the DCC peptide coupling reaction where HOBt is included as an additive. In order to reduce the epimerization level when using carbodiimides as coupling reagent, it has been shown that when 1-hydroxy-1H-benzotriazole (HOBt) was included as an additive, yields increased and epimerization levels decreased. However, when using these two reagents together, this side reaction can occur yielding the diazetidine by-product.
Music: Whisper – Mokka






![BDDC Coupling Mechanism | Organic Chemistry
The mechanism for the peptide coupling reaction involving an amine and a carboxylic acid using Bis[[4-(2,2-dimethyl-1,3-dioxolyl)]methyl]- carbodiimide (BDDC) as the coupling agent.
Music: Science – Mokka BDDC Coupling Mechanism | Organic Chemistry](https://i.ytimg.com/vi/PMHjlEpFB1k/mqdefault.jpg)



