Methyldopa EP Impurity A CAS 6739-31-7（free base）
| CAS No. | 6739-31-7（free base） |
| Molecular Formula | C11H15NO4 |
| Molecular Weight | N/A |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
As a certified reference material (CRM), Methyldopa EP Impurity A meets the metrological traceability requirements of ISO/IEC 17025 laboratories. Batch-to-batch consistency is monitored via control charts to guarantee comparable assigned values across lots.
Methyldopa EP Impurity A (CAS 6739-31-7（free base）) is a certified pharmaceutical impurity reference standard with the molecular formula C11H15NO4HCl and a molecular weight of 261.70 g/mol.
Based on its molecular formula C11H15NO4HCl, Methyldopa EP Impurity A contains a nitrogen-containing heterocyclic scaffold, an amide group, a hydroxyl group, an ether linkage, chlorine substitution; these features give the compound characteristic absorption bands in UV spectroscopy. The molecular weight of 261.70 g/mol is directly relevant to the identification of the molecular ion in mass spectrometry. Halogen substitution (F/Cl/Br/I) produces a distinctive isotope pattern in mass spectrometry, a valuable aid for qualitative confirmation.
This reference standard supports related-substances testing and method development in line with ICH Q3A/Q3B guidance on impurity control, and is suitable for system suitability testing and forced-degradation studies.
Physical & Chemical Properties
| Molecular Formula | C11H15NO4 HCl |
| Molecular Weight | 261.70 g/mol |
| Appearance | Off-white to pale yellow crystalline powder. (slight halide-like odor) |
| Purity | 97%+ |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry, keep tightly closed to prevent evaporation |
| Solubility (reference) | Soluble in methanol, ethanol, DMSO |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Hygroscopic; reseal immediately after opening; Contains ester bond; hydrolyzes under strong alkaline conditions |
| Degree of Unsaturation (DBE) | 4.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| Halogen Content | Cl-containing |
| Nitrogen Atoms | 1 |
Related Methyldopa Standards
- Methyldopa EP Impurity D (CAS 1369423-51-7)
- Methyldopa EP Impurity D (CAS 2799-15-7)
- Methyldopa EP Impurity D HBr (CAS 2799-15-7 (free base))
- Methyldopa EP Impurity B HCl (CAS 35026-10-9)
- Methyldopa EP Impurity C (CAS 39948-18-0)
- Methyldopa EP Impurity C (CAS 5486-79-3)
- DL-Methyldopa (CAS 55-40-3)
- Methyldopa EP Impurity A (CAS 6739-31-7)
Recommended Standards
- Esomeprazole Impurity 52 (CAS 704910-88-3)
- Lesinurad Impurity 11 (CAS CATO-C4X-147811)
- Trazodone Impurity 107 (CAS CATO-C4X-1772107)
- 103404-81-5 3-Indoxyl phosphate,di-P-toluidinium salt p-toluidine hemi(1H-indol-3-yl phosphate) (CAS 103404-81-5)
- 3-(Benzyloxy)benzenethiol (CAS 431878-96-5)
- Methyl 2-amino-8H-indeno[1,2-d]thiazole-5-carboxylate (CAS 1245648-02-5)
- Naphtho[2,3-α]pyrene (CAS 196-42-9)
- (R)-1-(6-Ethoxy-2-(methylthio)pyrimidin-4-yl)pyrrolidin-3-ol (CAS 1354019-51-4)
- Benzyl (S)-2-carbamoyl-5-oxopyrrolidine-1-carboxylate (CAS 171738-41-3)
- Semaglutide Impurity 165 (CAS CATO-C4X-2226165)
Why CATO?
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