Lorazepam EP Impurity A CAS 2958-36-3
| CAS No. | 2958-36-3 |
| Molecular Formula | C13H9Cl2NO |
| Molecular Weight | 266.12 g/mol |
| Category | Pharmacopoeial Impurity Standards / EP Impurities |
| Availability | In Stock |
Chemical Structure
Description
Compared with other compounds in its class, the molecular weight of 266.12 g/mol gives Lorazepam EP Impurity A distinctive chromatographic separation conditions and mass-spectrometry parameter settings.
Lorazepam EP Impurity A (CAS 2958-36-3) is a certified pharmaceutical impurity reference standard with the molecular formula C13H9Cl2NO and a molecular weight of 266.12 g/mol.
Owing to a nitrogen-containing heterocyclic scaffold, an amide group, a hydroxyl group, an ether linkage, chlorine substitution, Lorazepam EP Impurity A is typically pale yellow to yellow low-melting solid. Its solid-state physicochemical attributes — including a molecular weight of 266.12 g/mol — guide the selection of appropriate sample preparation and analytical techniques. The high carbon-to-hydrogen ratio imparts good lipophilicity, allowing liquid-liquid extraction with non-polar solvents such as n-hexane or ethyl acetate.
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 | C13H9Cl2NO |
| Molecular Weight | 266.12 g/mol |
| Purity | >95% |
| Storage | Store at 2-8°C, protect from light, keep tightly closed to prevent evaporation |
| Solubility (reference) | Soluble in chloroform, dichloromethane, ethyl acetate, DMSO |
| Stability | May oxidize slowly on prolonged air exposure; Light-sensitive; avoid direct strong light |
| Degree of Unsaturation (DBE) | 9.0 |
| UV Absorption | UV-absorbing |
| Structural Features | Aromatic ring present |
| CAS Registry Year (est.) | 1957 |
| Halogen Content | Cl-containing |
| Nitrogen Atoms | 1 |
Related Lorazepam Standards
- Lorazepam Impurity 12 (CAS 837-58-1)
- Lorazepam Impurity 11 (CAS CATO-C4X-104111)
- Lorazepam EP Impurity E (CAS 93955-15-8)
- Lorazepam Impurity 2 (CAS 773871-49-1)
- Lorazepam Impurity 21 (CAS CATO-C4X-104121)
- Lorazepam USP Related Compound D (CAS 54643-79-7)
- (S)-Lorazepam (CAS 110032-65-0)
- (R)-Lorazepam (CAS 91402-80-1)
Recommended Standards
- Diclofenac EP Impurity B (CAS 22121-58-0)
- (2-amino-5-chlorophenyl)(3-chlorophenyl)methanone (CAS 5625-08-1)
- Diclofenac potassium Impurity 7 (CAS CATO-C4X-10517)
- α-(Fluoromethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzenemethanol (CAS 2845281-96-9)
- Ammoxetine Impurity 11 (CAS CATO-C4X-335711)
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- 3-(Furo[3,2-b]pyridin-6-yl)prop-2-yn-1-ol (CAS 1228665-83-5)
- 2,2-Dimethyl-N-((2-methyl-2H-1,2,3-triazol-4-yl)methyl)thietan-3-amine (CAS 1871745-37-7)
- N-(3-Bromophenyl)-2-((4-(4-bromophenyl)-5-(pyridin-3-yl)-4H-1,2,4-triazol-3-yl)thio)acetamide (CAS 763138-77-8)
- tert-Butyl7-methyl-1,2,3,5-tetrahydro-4H-benzo[e][1,4]diazepine-4-carboxylate (CAS 886364-42-7)
- (1-Cyanocyclopropyl)methyl methanesulfonate (CAS 186387-76-8)
- n-[1-(3-fluoro-4-methoxyphenyl)ethyl]sulfamide (CAS 1280985-10-5)
- D-[Phe]6-Semaglutide (CAS CATO-CPTD788633)
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