Leflunomide EP Impurity E CAS 208401-20-1
| CAS No. | 208401-20-1 |
| Molecular Formula | C12H9F3N2O2 |
| Molecular Weight | 270.21 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
Recommended for quantitative analysis by HPLC, GC, LC-MS/MS, or GC-MS as an external calibration standard; it can also be used for spiked-recovery experiments, LOD/LOQ determination, and LC-MS/MS multiple-reaction-monitoring (MRM) calibration.
Leflunomide EP Impurity E (CAS 208401-20-1) is a certified pharmaceutical impurity reference standard with the molecular formula C12H9F3N2O2 and a molecular weight of 270.21 g/mol.
Leflunomide EP Impurity E (C12H9F3N2O2) contains a nitrogen-containing heterocyclic scaffold, an amide group, a hydroxyl group, an ether linkage, fluorine substitution. It is notably hygroscopic, halogen substitution raises its density and boiling point, its high carbon-to-hydrogen ratio confers good lipid solubility, the carboxyl group imparts weak acidity; these physicochemical properties determine the optimal preparation and storage of its standard solutions. Halogen substitution (F/Cl/Br/I) produces a distinctive isotope pattern in mass spectrometry, a valuable aid for qualitative confirmation.
As a certified reference material (CRM), Leflunomide EP Impurity E 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.
Physical & Chemical Properties
| Molecular Formula | C12H9F3N2O2 |
| Molecular Weight | 270.21 g/mol |
| Appearance | Pale yellow to yellow crystalline powder. (slight halide-like odor, low volatility) |
| Purity | >90% |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry, keep tightly closed to prevent evaporation |
| Solubility (reference) | Soluble in DMSO, DMF, methanol |
| 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) | 8.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 2016 |
| Halogen Content | F-containing |
| Nitrogen Atoms | 2 |
Related Leflunomide Standards
- Leflunomide (CAS 75706-12-6)
- Leflunomide EP Impurity C (CAS 61643-23-0)
- Leflunomide EP Impurity F (CAS 1403564-06-6)
- Leflunomide EP Impurity B (Teriflunomide) (CAS 163451-81-8)
- Leflunomide-d4 (CAS 1189987-23-2)
- Leflunomide EP Impurity B-d4 (Teriflunomide-d4) (CAS 1185240-22-5)
- Leflunomide Impurity 20 (CAS 2734292-21-6)
- Leflunomide Impurity 2 (CAS 827029-20-9)
Recommended Standards
- Nilotinib Impurity 16 (CAS 641571-13-3)
- Teriflunomide Impurity 5 (CAS 220512-86-7)
- Bicalutamide Impurity 14 (Bicalutamide Epoxide Impurity) (CAS 90357-51-0)
- Teriflunomide Impurity 6 (CAS 62004-05-1)
- Finerenone Impurity 35 (CAS 1545905-35-8)
- Ledipasvir Impurity 22 (CAS CATO-C4X-331322)
- Flurbiprofen Impurity 24 (CAS 66202-86-6)
- 6-Fluoro-1-methylspiro[benzo[d][1,3]oxazine-4,4'-piperidin]-2(1H)-one (CAS 1036926-64-3)
- 6-O-Nicotinoylbarbatin C (CAS 1015776-92-7)
- Tert-butyl 3-pentylazetidine-1-carboxylate (CAS 1803611-23-5)
- 2-(tert-Butyl)-1-cyclopropoxy-4-isopropylbenzene (CAS 1243288-48-3)
- (3-Methoxyphenyl)(oxazol-2-yl)methanone (CAS 898759-47-2)
- (1α,5α,6α)-3-Azabicyclo[3.1.0]hexan-6-ylmethanol hydrochloride (CAS 185561-91-5)
- Tirzepatide Impurity 44 (CAS CATO-C4X-324044)
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