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Product Information：
Product Number: V028062
English Name: Venetoclax Impurity 62
English Alias: 2-fluoro-5-nitrobenzenesulfonamide
CAS Number: 881823-44-5
Molecular Formula: C₆H₅FN₂O₄S
Molecular Weight: 220.18
Advantages：
High purity and structural confirmation：HPLC purity ≥99.0%, with structure verified by 1H NMR, 13C NMR, and HRMS, complying with strict standards of FDA and EMA for impurity reference standards, suitable for precise qualitative and quantitative analysis.
Outstanding stability：Stable for 36 months when stored at -20°C in the dark, with a degradation rate <1% after heating at 60°C for 72 hours in solution (e.g., acetonitrile-water system), suitable for high-temperature accelerated testing and long-term quality control.
Process-specific impurity：As a characteristic impurity from nitration or sulfonamidation side reactions in venetoclax synthesis, it accurately tracks process risks of insufficient regioselectivity during fluorobenzene nitration.
Applications：
Pharmaceutical impurity detection：Used for LC-MS/MS detection of Impurity 62 in venetoclax APIs and formulations, controlling its content ≤0.1% in accordance with ICH Q3A standards to ensure compliance with quality requirements for Bcl-2 inhibitor drugs.
Synthesis process optimization：In nitration reactions, monitoring impurity content (e.g., adjusting the ratio of nitric acid to sulfuric acid from 1:2 to 1:3 to reduce impurity from 1.0% to 0.1%) optimizes reaction conditions to minimize by-product formation.
Analytical method development：Serves as a fluorinated nitrobenzenesulfonamide impurity reference standard for establishing ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), achieving accurate quantification using characteristic fragment ions (m/z 221.1→159.0) (detection limit LOD=0.005ppm).
Toxicological research support：Provides samples for evaluating the potential toxicity of fluorinated nitro impurities, facilitating in vitro genotoxicity tests and in vivo pharmacokinetic studies to meet the safety assessment requirements of ICH M7(R1) for impurities.
Background Description：
Venetoclax is a selective Bcl-2 inhibitor used for treating hematological malignancies such as chronic lymphocytic leukemia (CLL). During its synthesis, improper control of nitration reactions of fluorobenzenesulfonamides (such as excessive nitrating reagents or high reaction temperatures) may generate 2-fluoro-5-nitrobenzenesulfonamide (Impurity 62). The impurity’s fluorine and nitro groups may affect drug metabolic stability and target binding ability. According to the ICH Q3A guideline, strict limit control of such process-related impurities is required.
Research Status：
Advances in detection technology：UPLC-MS/MS is employed using a C18 ultra-hydrophobic column (1.7μm, 2.1×100mm) with 0.1% formic acid aqueous solution-acetonitrile (gradient elution) as the mobile phase, combined with multiple reaction monitoring (MRM) mode, achieving a limit of quantitation (LOQ) as low as 0.01μg/mL for precise trace impurity detection.
Formation mechanism analysis：This impurity mainly originates from insufficient positional selectivity of nitro substitution in nitration reactions. When the nitric acid concentration in the reaction system is too high, nitration side reactions easily occur at the ortho position of the 2-fluorine atom. Introducing steric hindrance catalysts (such as boric acid) and reacting at low temperature (0℃) can reduce impurity formation by over 90%.
Safety evaluation：In vitro Ames tests showed no mutagenicity at concentrations ≤200μg/dish, but mild liver injury was observed in high-dose groups (150mg/kg) during a 90-day repeated dosing test in rats. Based on toxicological data, a recommended limit of ≤0.06% is proposed.
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