5-Amino-2-benzimidazolethiol
- Createtime： 2026-04-14
- Updatetime： 2026-09-30
Product Details
| useage |
Industrial use
|
| deliveryInfo |
|
| appearance |
powder
|
| Molecular Weight |
165.22
|
| aliasen |
|
| supplyCapacity |
50000MT/Month
|
| harbor |
Qingdao,China
|
| minorder |
1KG
|
| Appearance |
off-white powder
|
Shandong Huashang Chemical Co., Ltd. is a high-tech enterprise focused on industry of fine chemicals research and develop, produce and sale. Shandong Huashang Chemical Co., Ltd. is located in Shan Dong Ji Nan China. we have the ability to provide you high quality products. More than 90 % of our products are exported to developed countries and regions such as north America, Europe, Japan, South Korea and the Middle East.
5-Amino-2-benzimidazolethiol
1. Basic Information
Name: 5-Amino-2-benzimidazolethiol
Alias: 5-Amino-1H-benzimidazole-2-thiol, 2-Mercapto-5-aminobenzimidazole
CAS No.: 2818-66-8
Molecular Formula: C7H7N3S
Molecular Weight: 165.22
Category: Amino mercapto benzimidazole fused heterocyclic pharmaceutical & corrosion inhibitor intermediate
2. Physical and Chemical Properties
Physical Properties
- Appearance: Off-white to pale gray crystalline powder
- Odor: Faint sulfur mercaptan odor
- Solubility: Soluble in dilute acid, dilute alkali, DMSO, hot DMF; slightly soluble in hot methanol/ethanol; insoluble in cold water, aliphatic hydrocarbons
- Melting Range: 270–276 °C (decomposes with sulfur-containing gas release)
- Hygroscopy: Slightly hygroscopic under high humidity
- Aqueous Property: Amphoteric compound; thiol group weakly acidic, amino group weakly alkaline
Chemical Properties
- Molecular Structure: Benzimidazole core with amino substituent at C5 and mercapto (-SH) at C2; tautomerism exists between thiol and thione
- Mercapto reactivity: Undergoes S-alkylation, disulfide oxidative coupling, metal chelation; easily oxidized to disulfide in air
- Amino group reactivity: Capable of diazotization, acylation, condensation to construct drug side chains and dye chromophores
- Imidazole ring characteristic: Forms stable coordination complexes with transition metal ions (Cu, Zn, Ag)
- Thermal Stability: Stable below 240 °C; high-temperature decomposition releases toxic sulfur fumes
- Photostability: Highly light-sensitive; UV irradiation accelerates oxidation and darkens to gray-black
- Compatibility: Compatible with polar aprotic solvents; incompatible with strong oxidants, heavy metal salts, hydrogen peroxide
3. Main Application Fields
1. Pharmaceutical Synthetic Intermediate (Core Application)
Key raw material for anti-ulcer, anti-fungal, anti-parasitic benzimidazole APIs; mercapto group serves as core binding site for target enzyme inhibition
2. Metal Corrosion Inhibitor
Organic thiol chelating agent for copper, steel, alloy anti-rust treatment in cooling water and metal surface treatment
3. Dye & Fluorescent Probe Intermediate
Precursor for sulfur-containing heterocyclic azo dyes and metal ion fluorescent detection probes
4. HPLC Reference Standard
Chromatographic standard for benzimidazole thiol intermediate purity testing
4. Quality Specification Table
| Test Item | Standard Specification |
| CAS Number | 2818-66-8 |
| Molecular Formula | C7H7N3S |
| Appearance | Uniform pale off-white powder without black oxidized impurities |
| HPLC Purity | Pharma Grade ≥99.0% |
| Water Content (KF) | ≤0.30% |
| Melting Decomposition Range | 270–276 °C |
| Disulfide Oxide Impurity | ≤0.20% |
| Residue on Ignition | ≤0.10% |
| Single Unknown Impurity | ≤0.10% |
| Heavy Metals (Pb) | ≤10 ppm |
| Packaging | Nitrogen-purged amber vacuum aluminum foil bags / PE-lined fiber drums |
| Storage Condition | Hermetically sealed cool dark warehouse below 25 °C; isolate from air, light and oxidants to prevent oxidation |
| Transportation Requirement | Light-sensitive sulfur heterocyclic solid, light-proof sealed packaging |
| Shelf Life | 18 months under nitrogen-filled vacuum sealed storage |
Safety Warning
Irritant sulfur-containing heterocyclic powder. Dust irritates eyes, respiratory tract and skin; mercaptan vapor causes nasal discomfort and headache. All operations must be carried out in ventilated fume hoods with dust respirators and chemical-resistant gloves. Avoid exposure to air/UV light to prevent oxidation; prohibit mixing with strong oxidants to avoid violent redox reaction. Waste liquid recovered by solvent distillation and neutralized; solid waste classified as sulfur-containing organic hazardous waste and disposed by licensed professional hazardous waste institutions.
