General Description
White tabular crystals.
Reactivity Profile
An amine. Neutralizes acids to form salts plus water. These acid-base reactions are exothermic. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated in combination with strong reducing agents, such as hydrides. May be shock sensitive.
Air & Water Reactions
Insoluble in water.
Health Hazard
ACUTE/CHRONIC HAZARDS: When heated to decomposition this compound emits highly toxic fumes.
Fire Hazard
Flash point data for this chemical are not available. BENZIMIDAZOLE(51-17-2) is probably combustible.
Chemical Properties
white crystals
Uses
Usually used as template compound in the preparation of molecularly imprinted polymer via electropolymerization and electrodeposition of pyrrole on a pencil graphite electrode,and also used in the preparation of benzimidazolium surfactant, 1-hexadecyl-1H-benzimidazole.
Definition
ChEBI: 1H-benzimidazole is the 1H-tautomer of benzimidazole. It is a benzimidazole and a polycyclic heteroarene. It is a conjugate acid of a benzimidazolide. It is a tautomer of a 4H-benzimidazole, a 2H-benzimidazole and a 3aH-benzimidazole.
Preparation
Benzimidazole is synthesized by cyclizing o-phenylenediamine with formic acid. A mixture of o-phenylenediamine and formic acid is heated in a water bath for 2 hours, then cooled. The pH is adjusted to 10 using 10% sodium hydroxide solution, followed by filtration of the precipitated solid. The solid is washed with cold water to obtain the crude product (yield: 90%). The crude product is then refluxed in water, decolorized with activated carbon, and hot-filtered. Upon cooling the filtrate to room temperature, the purified product is collected by filtration, washed with cold water, and dried at 100°C to obtain the final product.
Pharmacology
The mode of action of benzimidazoles has been described
in several comprehensive reviews (1,32,33). The primary
mode of action of benzimidazoles has been identified as
the specific binding to the β-subunit of fungal tubulin and,
consequently, an interference with microtubule assembly.
Microtubules are major components of the fungal
cytoskeleton and are involved in meiosis and mitosis, both
of which are blocked in the presence of benzimidazoles.
Purification Methods
It crystallises from water or aqueous EtOH (charcoal) and is dried at 100o for 12hours. [Beilstein 23 H 131, 23/6 V 196.]
References
[1] YEUAN TING LEE Chern E O Yi Jer Tan. Benzimidazole and its derivatives as cancer therapeutics: The potential role from traditional to precision medicine[J]. Acta Pharmaceutica Sinica. B, 2023, 13 2: Pages 478-497. DOI:
10.1016/j.apsb.2022.09.010.
[2] SHEJUTI RAHMAN BRISHTY. A Comprehensive Account on Recent Progress in Pharmacological Activities of Benzimidazole Derivatives.[J]. ACS Applied Energy Materials, 2021: 762807. DOI:
10.3389/fphar.2021.762807.
[3] M ASHFAQ. Synthetic thioamide, benzimidazole, quinolone and derivatives with carboxylic acid and ester moieties: a strategy in the design of antituberculosis agents.[J]. Current medicinal chemistry, 2014: 911-931. DOI:
10.2174/09298673113206660302.
[4] EL-ON J. Benzimidazole treatment of cystic echinococcosis[J]. Acta tropica, 2003, 85 2: Pages 243-252. DOI:
10.1016/S0001-706X(02)00217-6.
