Crisaborole Impurity 21 CAS CATO-C4X-202121
| CAS No. | CATO-C4X-202121 |
| Molecular Formula | C21H16BrNO4 |
| Molecular Weight | 426.26 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
As a certified reference material (CRM), Crisaborole Impurity 21 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.
CATO supplies Crisaborole Impurity 21 (CAS CATO-C4X-202121), a pharmacopoeial impurity reference standard (molecular formula C21H16BrNO4, MW 426.26 g/mol) used for the identification and quantification of trace impurities in APIs.
The molecular framework of Crisaborole Impurity 21 (C21H16BrNO4) is characterized by a flavonoid core, an amide group, a hydroxyl group, an ether linkage, bromine substitution. In reversed-phase chromatography, its retention is governed primarily by the protonation state of its nitrogen-containing groups, which provides a practical basis for HPLC-UV/DAD or LC-MS method development. The presence of an aromatic ring or conjugated system gives the compound characteristic absorption bands in the UV-Vis region, making it well suited to UV or diode-array detection (DAD).
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 | C21H16BrNO4 |
| Molecular Weight | 426.26 g/mol |
| Appearance | Pale yellow to yellow crystalline powder. (slight halide-like odor) |
| Purity | >95% |
| Storage | Store at room temperature, protect from light, keep sealed and dry |
| Solubility (reference) | Soluble in methanol, acetonitrile, DMSO, water (slightly soluble) |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light; Contains ester bond; hydrolyzes under strong alkaline conditions |
| Degree of Unsaturation (DBE) | 14.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| Halogen Content | Br-containing |
| Nitrogen Atoms | 1 |
Related Crisaborole Standards
- Crisaborole impurity 110 (CAS CATO-C4X-2021110)
- Crisaborole lmpurity 74 (CAS CATO-C4X-202174)
- Crisaborole lmpurity 75 (CAS CATO-C4X-202175)
- Crisaborole Impurity 20 (CAS CATO-C4X-202120)
- Crisaborole Impurity 146 (CAS CATO-C4X-2021146)
- Crisaborole impurity 123 (CAS CATO-C4X-2021123)
- Crisaborole Impurity 50 (CAS CATO-C4X-202150)
- Crisaborole Impurity 137 (CAS CATO-C4X-2021137)
Recommended Standards
- Canagliflozin Impurity 18 (CAS CATO-C4X-112318)
- 4-Chloro-3,5-dibromo-2-iodoanisole (CAS 1160574-51-5)
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- 9-(4-Bromobutyl)-N-(2,2,2-trifluoroethyl)-9H-fluorene-9-carboxamide (CAS 182438-98-8)
- Oseltamivir Impurity 51 (CAS CATO-C4X-172051)
- Midecamycin Impurity 25 (CAS CATO-C4X-312225)
- Cinacalcet Impurity 75 (CAS CATO-C4X-105975)
- (2R,3R,4S,5R,6S)-2-(Acetoxymethyl)-6-(2-ethoxy-4-formylphenoxy)tetrahydro-2H-pyran-3,4,5-triyl triacetate (CAS 121358-45-0)
- 3-(Benzylamino)-4-((4-nitrophenyl)amino)-4-oxobutanoic acid (CAS 2096495-87-1)
- 5-(Hydroxymethyl)-4-methyloxazolidin-2-one (CAS 1781899-69-1)
- Pruvanserin HCl (CAS 443144-27-2)
- tert-Butyl N-[trans-4-methylpyrrolidin-3-yl]carbamate (CAS 107610-73-1)
- 5-Oxo-4,5-dihydropyrazolo[1,5-a]pyrimidine-2-carboxylic acid (CAS 197367-83-2)
- Des-Tyr10-Tirzepatide (CAS CATO-CPTD788680)
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