Niclosamide Impurity 4 CAS 16739-21-2
| CAS No. | 16739-21-2 |
| Molecular Formula | C13H7Cl3N2O4 |
| Molecular Weight | 361.56 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
Based on its molecular formula C13H7Cl3N2O4, Niclosamide Impurity 4 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 361.56 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.
CATO supplies Niclosamide Impurity 4 (CAS 16739-21-2), a pharmacopoeial impurity reference standard (molecular formula C13H7Cl3N2O4, MW 361.56 g/mol) used for the identification and quantification of trace impurities in APIs.
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.
The assigned purity is verified by mass-balance and quantitative NMR (qNMR) approaches, with the expanded uncertainty reported at a 95% confidence level (k=2). Batch homogeneity and stability are independently assessed for every lot.
Physical & Chemical Properties
| Molecular Formula | C13H7Cl3N2O4 |
| Molecular Weight | 361.56 g/mol |
| Appearance | Pale yellow to yellow crystalline powder. (slight halide-like odor, low volatility) |
| Purity | >95% |
| Storage | Store at 2-8°C, protect from light, keep sealed and dry |
| 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) | 10.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1961 |
| Halogen Content | Cl-containing |
| Nitrogen Atoms | 2 |
Related Niclosamide Standards
- 13C6-Niclosamide hydrate (CAS 1325559-12-3)
- Niclosamide-13C6 (CAS 1325808-64-7)
- Niclosamide Impurity 2 (CAS 16739-20-1)
- Niclosamide (CAS 50-65-7)
- Niclosamide Impurity 3 (CAS 4638-49-7)
- Niclosamide Impurity 5 (CAS 32853-24-0)
- Niclosamide Monohydrate (CAS 73360-56-2)
- Niclosamide Piperazine Salt (CAS 34892-17-6)
Recommended Standards
- Clindamycin Palmitate Impurity 100 (CAS 2839928-15-1)
- Docosahexaenoic Acid-d5 Ethyl Ester (CAS 159146-01-7)
- Pregabalin Impurity 144 (CAS CATO-C4X-1312144)
- (±)-Glyceryl-1,1,2,3,3-d5 1-Monooleate (CAS 565183-24-6)
- Nicardipine Impurity 48 (CAS CATO-C4X-171048)
- Amlodipine Impurity N20 (CAS 2170104-02-4)
- Bevantolol Impurity 20 (CAS CATO-C4X-241120)
- Isobutyric Acid (CAS 79-31-2)
- (R)-tert-Butyl 3-((2-chloro-6-methylpyrimidin-4-yl)amino)pyrrolidine-1-carboxylate (CAS 1261234-31-4)
- Ethyl 2-(benzylamino)-5-chloronicotinate (CAS 1186405-01-5)
- 3-(4-(tert-Butyl)phenyl)-5-((3-fluorobenzyl)thio)-4H-1,2,4-triazol-4-amine (CAS 575462-59-8)
- 6-bromo-8-(bromomethyl)quinoline (CAS 926207-02-5)
- N-Butyl-3,5-dimethylaniline (CAS 13342-26-2)
- Semaglutide impurity 261 (CAS CATO-C4X-2226261)
Why CATO?
- ISO 17034 accredited reference material producer (CNAS + ANAB dual accreditation)
- 130,000+ catalog items in stock, COA supplied with every batch
- Worldwide shipping with full export documentation (HS code guidance available)
- Technical support: +86 18665070610 / Nicole.chen@cato-chem.com