Benzimidazole
| Benzimidazole | |
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1H-benzimidazole |
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| Identifiers | |
| CAS number | 51-17-2  |
| PubChem | 5798 |
| ChemSpider | 5593 |
| UNII | E24GX49LD8 |
| KEGG | C02009 |
| ChEBI | CHEBI:41275 |
| ChEMBL | CHEMBL306226 |
| Jmol-3D images | Image 1 Image 2 |
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| Properties | |
| Molecular formula | C7H6N2 |
| Molar mass | 118.14 g mol−1 |
| Melting point |
170–172 °C |
| Hazards | |
| MSDS | External MSDS |
| EU classification | Harmful (Xn) |
| R-phrases | R20 R21 R22 R36 R37 R38 |
| S-phrases | S26 S36 |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Benzimidazole is a heterocyclic aromatic organic compound. This bicyclic compound consists of the fusion of benzene and imidazole. The most prominent benzimidazole compound in nature is N-ribosyl-dimethylbenzimidazole, which serves as an axial ligand for cobalt in vitamin B12.[1]
Benzimidazole, in an extension of the well-elaborated imidazole system, has been used as carbon skeletons for N-heterocyclic carbenes. The NHCs are usually used as ligands for transition metal complexes. They are often prepared by deprotonating an N,N'-disubstituted benzimidazolium salt at the 2-position with a base.[2][3]
Contents |
[edit] Preparation
Benzimidazole is commercially available. The usual synthesis involves condensation of o-phenylenediamine with formic acid,[4] or the equivalent trimethyl orthoformate:
- C6H4(NH2)2 + HC(OCH3)3 → C6H4N(NH)CH + 3 CH3OH
By altering the carboxylic acid used, this method is generally able to afford 2-substituted benzimidazoles.[4] Benzimidazole also has fungicidal properties. It acts by binding to the fungal microtubules and stopping hyphal growth. It also binds to the spindle microtubules and blocks nuclear division.
[edit] See also
- Benzimidazoline
- Albendazole, a common use anthelmintic.
- Indole, an analog with CH in place of nitrogen in position 3.
- Purine, an analog with two additional nitrogen atoms in the six-membered ring.
- Simple aromatic rings
- Triclabendazole, most common drug against liver flukes
- polybenzimidazole, a high performance fiber
- Mebendazole, a highly effective broad spectrum antihelminitic
[edit] References
- ^ H. A. Barker, R. D. Smyth, H. Weissbach, J. I. Toohey, J. N. Ladd, and B. E. Volcani (February 1, 1960). "Isolation and Properties of Crystalline Cobamide Coenzymes Containing Benzimidazole or 5,6-Dimethylbenzimidazole". Journal of Biological Chemistry 235 (2): 480–488. PMID 13796809. http://www.jbc.org/cgi/reprint/235/2/480.
- ^ R. Jackstell, A. Frisch, M. Beller, D. Rottger, M. Malaun and B. Bildstein (2002). "Efficient telomerization of 1,3-butadiene with alcohols in the presence of in situ generated palladium(0)carbene complexes". Journal of Molecular Catalysis A: Chemical 185 (1–2): 105–112. doi:10.1016/S1381-1169(02)00068-7.
- ^ H. V. Huynh, J. H. H. Ho, T. C. Neo and L. L. Koh (2005). "Solvent-controlled selective synthesis of a trans-configured benzimidazoline-2-ylidene palladium(II) complex and investigations of its Heck-type catalytic activity". Journal of Organometallic Chemistry 690 (16): 3854–3860. doi:10.1016/j.jorganchem.2005.04.053.
- ^ a b E. C. Wagner and W. H. Millett (1943), "Benzimidazole", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv2p0065; Coll. Vol. 2: 65.
[edit] Further reading
- Grimmett, M. R. (1997). Imidazole and benzimidazole synthesis. Boston: Academic Press. ISBN 0-12-303190-7.
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