CAS: 5417-13-0
Synonym: 5-(hydroxyimino)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione, DMVA
Molecular Formula: C6H7N3O4
Molecular Weight: 185.1 [gr/mol]
Oxyma-B
One of the most effective oxime additives currently available for racemization-free peptide synthesis comparable with OxymaPure® and HOAt.
Peptide/amide bond synthesis
Liquid-phase peptide synthesis (LPPS) with Oxyma-B
Yield and racemization during the formation of Z-Phg-Pro-NH2 in DMF (solution synthesis) (1)
| Entry | Coupling reagent/strategy | Yield (%) | D/L (%) |
| 1 | HOAt/DIC | 91.5 | 3.9 |
| 2 | HOBt/DIC | 94.3 | 11.0 |
| 3 | Oxyma/DIC | 94.4 | 0.9 |
| 5 | Oxyma-B/DIC | 90.0 | 1.0 |
Couplings were conducted without preactivation, at room temperature.
Yield and racemization during the formation in solution of Z-Phe-Val-Pro-NH2 in DMF in solution from Z-Phe-Val-OH and H-Pro-NH2 (1)
| Entry | Additive | Yield (%) | D/L (%) |
| 1 | HOAt/DIC | 97.6 | 5.9 |
| 2 | HOBt/DIC | 96.2 | 14.8 |
| 3 | Oxyma-B/DIC | 90.7 | 5.1 |
| 4 | OxymaPure/DIC | 91.9 | 7.7 |
Solid-Phase Peptide Synthesis (SPPS)
Racemization
Racemization during the incorporation of Fmoc-Cys(Trt)-OH in solid-phase to render H-Gly-Cys-Phe-NH2 in DMF
| Entry | Additive | D/L (%) |
| 1 | HOAt/DIC | 0.4 |
| 2 | HOBt/DIC | 0.5 |
| 3 | OxymaPure/DIC | 0.3 |
| 4 | Oxyma-B/DIC | 0.3 |
Racemization during the incorporation of Fmoc-His(Trt)-OH in solid-phase to render H-Gly-His-Phe-NH2 in DMF (3)
| Entry | Coupling Reagent | D/L (%) |
| 1 | HOAt/DIC | 1.9 |
| 2 | HOBt/DIC | 5.1 |
| 3 | OxymaPure/DIC | 3.0 |
| 4 | Oxyma-B/DIC | 1.0 |
Synthesis of challenging/difficult peptides
Percentage purity of the pentapeptide H-Tyr-Aib-Aib-Phe-Leu-NH2 versus the tetrapeptide side-product des-Aib (H-Tyr-Aib-Phe-Leu-NH2 during solid-phase assembly (4)
| Entry | Coupling reagents | Pentapeptide (%) | des-Aib (%) |
| 1 | DIC/HOBt | 8.4 | 83.1 |
| 2 | DIC/HOAt | 37.5 | 60.2 |
| 3 | DIC/OxymaPure | 42.8 | 50.4 |
| 5 | DIC/Oxyma-B | 26.4 | 61.1 |
Stability
Oxyma-B Compatibility with automated synthesis
Oxyma-B is compatible for use in automated synthesizers including microwave-assisted synthesis. OxymaPure®/DIC combination is stable at 900C of microwave conditions.
Storage stability
The material remains virtually unchanged upon both room temperature and 54oC oven storage. Therefore, Oxyma B, as long as it is kept in its intact original packaging, may safely be stored for at least one year under normal room temperature conditions.
Green Chemistry
Oxyma-B Compatibility with green solvents
Oxyma-B is compatible for use in automated synthesizers including microwave-assisted synthesis. OxymaPure®/DIC combination is stable at 900C of microwave conditions.
Oxyma-B can be used with carbodiimides in the PolarClean/NBP binary green solvent system.