2-n-Propyl-4-methyl-6-(1-methylbenzimidazole-2-yl)benzimidazole, （CAS 152628-02-9）

Provides a comprehensive overview of 2-n-Propyl-4-methyl-6-(1-methylbenzimidazole-2-yl)benzimidazole, covering its physicochemical properties, synthesis methods, analytical detection, safety storage, and applications. It highlights the compound’s role as a key impurity in telmisartan production and its potential in organic synthesis.介绍2-n-Propyl-4-methyl-6-(1-methylbenzimidazole-2-yl)benzimidazole的理化性质、合成方法、分析检测、安全储存及应用领域，重点探讨其作为替米沙坦中间体的作用。

• Common name: Telmisartan intermediate (bisimidazole)
• Molecular formula: C19H20N4
• Molecular weight: 304.39
• Physical and chemical properties
• [ Density ]: 1.2±0.1g/cm3
• [ Boiling point ]: 584.8±52.0℃ at 760 mmHg
• [ Molecular formula ]: C19H20N4
• [ Molecular weight ]: 304.389
• [ Flash point ]: 307.5±30.7℃
• [ Precise quality ]: 304.168793
• [ PSA ]：46.50000
• [ LogP ]：4.76
• [ Appearance ]: Gray powder
• [ Vapor pressure ]: 0.0±1.6mmHg at 25℃
• [ Refractive index ]: 1.673

​1. Physicochemical Properties

• ​Molecular Formula: C₁₉H₂₀N₄
• ​Molecular Weight: 304.40 g/mol
• ​CAS Number: 152628-02-9
• ​Alternative Name: Telmisartan Impurity A, 2-n-Propyl-4-methyl-6-(1′-methylbenzimidazole-2-yl)benzimidazole
• ​Structural Features:
  • Contains two benzimidazole rings with n-propyl (C₃H₇), methyl (CH₃), and isopropyl (C₃H₇) substituents.
  • Exhibits keto-enol tautomerism, which may influence its chemical reactivity.

​2. Synthesis and Applications

• ​Synthesis Routes:
  Prepared via condensation reactions of benzimidazole derivatives, including steps such as:
  1. Alkylation of 1-methylbenzimidazole with bromopropane under alkaline conditions.
  2. Cyclization with 4-methyl-2-n-propylbenzimidazoleone to form the dual benzimidazole structure.
• ​Applications:
  • ​Drug Impurity Reference: Serves as Key Impurity A in the quality control of telmisartan (an angiotensin II receptor antagonist).
  • ​Organic Synthesis Intermediate: Potential use in constructing polycyclic imidazole compound libraries.

​3. Analysis and Detection

• ​Detection Methods:
  • ​HPLC: Used for impurity quantification in pharmaceuticals (aligned with EP standards).
  • ​NMR/MS: Confirms structural identity and purity (molecular ion peak m/z 305.2, M+H⁺).
• ​Quality Control: Requires ≥99% purity, with total impurities ≤0.1%.

​4. Safety and Storage

• ​Toxicity: Low acute toxicity reported for benzimidazole derivatives; avoid direct contact.
• ​Storage Conditions: Store in a cool, dry place (2–8°C), protected from light and moisture.

​5. Research Insights

• ​Structure-Activity Relationships: Substituent positions on benzimidazole rings influence metabolic stability (e.g., methyl groups enhance oral bioavailability).
• ​Process Optimization: Microwave-assisted synthesis improves yields to >85% and reduces reaction time.

​6. Supply Chain Information

• ​Procurement Channels: Available through chemical databases (e.g., Chem960, Alfa Chemistry) for sample acquisition.