Oxyma

Oxyma is the common name for Ethyl cyano(hydroxyimino)acetate, a class of reagents used as additives to facilitate amide bond formation in peptide synthesis. The most widely used commercial form is Oxyma Pure, the ethyl ester of cyano(hydroxyimino)acetate. In peptide coupling, Oxyma is employed alongside carbodiimide reagents such as DIC or DCC to improve coupling efficiency and suppress racemization during bond formation.

Mechanistically, Oxyma helps generate a reactive ester intermediate that is more stable and less prone to side reactions than alternative activation pathways. This tends to reduce the formation of racemized products and certain byproducts, leading to higher yields and cleaner peptide syntheses. Oxyma is compatible with both solid-phase peptide synthesis (SPPS) and solution-phase approaches and is commonly used to replace or complement hazardous or less effective additives.

Compared to hydroxybenzotriazole (HOBt) and related compounds, Oxyma is often favored for safety reasons because it is less prone to explosive hazards while providing comparable or improved suppression of racemization and efficiency in many coupling scenarios. Nonetheless, standard precautions for handling organic reagents apply, including appropriate personal protective equipment and good ventilation.

Oxyma has become a standard reagent in modern peptide synthesis workflows and is available from multiple chemical suppliers. It is used across research and production settings to enhance coupling performance while minimizing side reactions associated with carbodiimide-mediated activations. See also DIC, DCC, HOBt, and peptide coupling.