Benzimidazole

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Benzimidazole
Benzimidazole 2D numbered.svg
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Names
Preferred IUPAC name
1H-1,3-Benzimidazole
Other names
1H-Benzo[d]imidazole
Identifiers
3D model (JSmol)
109682
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.075 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-081-4
3106
KEGG
PubChem CID
UNII
  • InChI=1S/C7H6N2/c1-2-4-7-6(3-1)8-5-9-7/h1-5H,(H,8,9) Yes check.svgY
    Key: HYZJCKYKOHLVJF-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C7H6N2/c1-2-4-7-6(3-1)8-5-9-7/h1-5H,(H,8,9)
    Key: HYZJCKYKOHLVJF-UHFFFAOYAX
  • c1ccc2c(c1)[nH]cn2
Properties
C7H6N2
Molar mass 118.139 g·mol−1
Melting point 170 to 172 °C (338 to 342 °F; 443 to 445 K)
Acidity (pKa)12.8 (for benzimidazole) and 5.6 (for the conjugate acid) [1]
Hazards
GHS labelling:
GHS-pictogram-exclam.svg
Warning
H302, H315, H319, H335
P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Benzimidazole is a heterocyclic aromatic organic compound. This bicyclic compound may be viewed as fused rings of the aromatic compounds benzene and imidazole. It is a white solid that appears in form of tabular crystals. [2]

Contents

Preparation

Benzimidazole is produced by condensation of o-phenylenediamine with formic acid, [3] or the equivalent trimethyl orthoformate:

C6H4(NH2)2 + HC(OCH3)3 → C6H4N(NH)CH + 3 CH3OH

2-Substituted derivatives are obtained when the condensation is conducted with aldehydes in place of formic acid, followed by oxidation. [4]

Reactions

Benzimidazole is a base:

C6H4N(NH)CH + H+ → [C6H4(NH)2CH]+

It can also be deprotonated with stronger bases:

C6H4N(NH)CH + LiH → Li [C6H4N2CH] + H2

The imine can be alkylated and also serves as a ligand in coordination chemistry. The most prominent benzimidazole complex features N-ribosyl-dimethylbenzimidazole, as found in vitamin B12. [5]

N,N'-Dialkylbenzimidazolium salts are precursors to certain N-heterocyclic carbenes. [6] [7]

Applications

Benomyl is a fungicide with a benzimidazole core Benomyl.png
Benomyl is a fungicide with a benzimidazole core

Benzimidazole derivatives are among the most frequently used ring systems for small molecule drugs listed by the United States Food and Drug Administration. [8] Many pharmaceutical agents belong to the benzimidazole class of compounds. For example:

In printed circuit board manufacturing, benzimidazole can be used as an organic solderability preservative.[ citation needed ]

Several dyes are derived from benzimidazoles. [9]

See also

Related Research Articles

Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen atom. Chemical compounds containing such rings are also referred to as furans.

<span class="mw-page-title-main">Acyl halide</span> Oxoacid compound with an –OH group replaced by a halogen

In organic chemistry, an acyl halide is a chemical compound derived from an oxoacid by replacing a hydroxyl group with a halide group.

<span class="mw-page-title-main">Imide</span> Class of chemical compounds

In organic chemistry, an imide is a functional group consisting of two acyl groups bound to nitrogen. The compounds are structurally related to acid anhydrides, although imides are more resistant to hydrolysis. In terms of commercial applications, imides are best known as components of high-strength polymers, called polyimides. Inorganic imides are also known as solid state or gaseous compounds, and the imido group (=NH) can also act as a ligand.

<span class="mw-page-title-main">Azo compound</span> Organic compounds with a diazenyl group (–N=N–)

Azo compounds are organic compounds bearing the functional group diazenyl.

<span class="mw-page-title-main">Imidazole</span> Chemical compound

Imidazole (ImH) is an organic compound with the formula C3N2H4. It is a white or colourless solid that is soluble in water, producing a mildly alkaline solution. In chemistry, it is an aromatic heterocycle, classified as a diazole, and has non-adjacent nitrogen atoms in meta-substitution.

<span class="mw-page-title-main">Oxazole</span> Chemical compound

Oxazole is the parent compound for a vast class of heterocyclic aromatic organic compounds. These are azoles with an oxygen and a nitrogen separated by one carbon. Oxazoles are aromatic compounds but less so than the thiazoles. Oxazole is a weak base; its conjugate acid has a pKa of 0.8, compared to 7 for imidazole.

Thiazole, or 1,3-thiazole, is a 5-membered heterocyclic compound that contains both sulfur and nitrogen. The term 'thiazole' also refers to a large family of derivatives. Thiazole itself is a pale yellow liquid with a pyridine-like odor and the molecular formula C3H3NS. The thiazole ring is notable as a component of the vitamin thiamine (B1).

<span class="mw-page-title-main">Triazine</span> Aromatic, heterocyclic compound

Triazines are a class of nitrogen-containing heterocycles. The parent molecules' molecular formula is C3H3N3. They exist in three isomeric forms, 1,3,5-triazines being common.

<span class="mw-page-title-main">Benzothiazole</span> Chemical compound

Benzothiazole is an aromatic heterocyclic compound with the chemical formula C
7
H
5
NS
. It is colorless, slightly viscous liquid. Although the parent compound, benzothiazole is not widely used, many of its derivatives are found in commercial products or in nature. Firefly luciferin can be considered a derivative of benzothiazole.

Thiazolidine is a heterocyclic organic compound with the formula (CH2)3(NH)S. It is a 5-membered saturated ring with a thioether group and an amine group in the 1 and 3 positions. It is a sulfur analog of oxazolidine. Thiazolidine is a colorless liquid. Although the parent thiazolidine is only of academic interest, some derivatives, i.e., the thiazolidines, are important, such as the antibiotic penicillin.

<span class="mw-page-title-main">Benzoxazole</span> Chemical compound

Benzoxazole is an aromatic organic compound with a molecular formula C7H5NO, a benzene-fused oxazole ring structure, and an odor similar to pyridine. Although benzoxazole itself is of little practical value, many derivatives of benzoxazoles are commercially important.

<i>o</i>-Phenylenediamine Chemical compound

o-Phenylenediamine (OPD) is an organic compound with the formula C6H4(NH2)2. This aromatic diamine is an important precursor to many heterocyclic compounds. OPD is a white compound although samples appear darker owing to oxidation by air. It is isomeric with m-phenylenediamine and p-phenylenediamine.

<span class="mw-page-title-main">Imidazolidine</span> Chemical compound

Imidazolidine is a heterocyclic compound (CH2)2(NH)2CH2. The parent imidazolidine is lightly studied, but related compounds substituted on one or both nitrogen centers are more common. Generally, they are colorless, polar, basic compounds. Imidazolidines are cyclic 5-membered examples of the general class of aminals.

<span class="mw-page-title-main">2,6-Xylidine</span> Chemical compound

2,6-Xylidine is an organic compound with the formula C6H3(CH3)2NH2. It is one of several isomeric xylidines. It is a colorless viscous liquid. Commercially significant derivatives are the anesthetics lidocaine, bupivacaine, mepivacaine, and etidocaine.

<span class="mw-page-title-main">2,4,6-Trimethylaniline</span> Chemical compound

2,4,6-Trimethylaniline is an organic compound with formula (CH3)3C6H2NH2. It is an aromatic amine that is of commercial interest as a precursor to dyes. It is prepared by selective monoamoniation of mesitylene, avoiding oxidation of the methyl groups. The resulting nitro compound is reduced to the aniline.

In chemistry, carbonylation refers to reactions that introduce carbon monoxide (CO) into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbonylation also refers to oxidation of protein side chains.

<span class="mw-page-title-main">4,4'-Dichlorodiphenyl sulfone</span> Chemical compound

4,4′-Dichlorodiphenyl sulfone (DCDPS) is an organic compound with the formula (ClC6H4)2SO2. Classified as a sulfone, this white solid is most commonly used as a precursor to polymers that are rigid and temperature-resistant such as PES or Udel.

<span class="mw-page-title-main">1-Methylimidazole</span> Chemical compound

1-Methylimidazole or N-methylimidazole is an aromatic heterocyclic organic compound with the formula CH3C3H3N2. It is a colourless liquid that is used as a specialty solvent, a base, and as a precursor to some ionic liquids. It is a fundamental nitrogen heterocycle and as such mimics for various nucleoside bases as well as histidine and histamine.

In organic chemistry, transalkylation is a chemical reaction involving the transfer of an alkyl group from one organic compound to another. The reaction is used for the transfer of methyl and ethyl groups between benzene rings. This is of particular value in the petrochemical industry to manufacture p-xylene, styrene, and other aromatic compounds. Motivation for using transalkylation reactions is based on a difference in production and demand for benzene, toluene, and xylenes. Transalkylation can convert toluene, which is overproduced, into benzene and xylene, which are under-produced. Zeolites are often used as catalysts in transalkylation reactions.

In industrial chemistry, carboalkoxylation is a process for converting alkenes to esters. This reaction is a form of carbonylation. A closely related reaction is hydrocarboxylation, which employs water in place of alcohols

References

  1. Walba, Harold; Isensee, Robert W. (1961). "Acidity Constants of Some Arylimidazoles and Their Cations". The Journal of Organic Chemistry. 26 (8): 2789–2791. doi:10.1021/jo01066a039.
  2. "Benzimidazole | CAMEO Chemicals | NOAA". cameochemicals.noaa.gov. Retrieved 2023-01-11.
  3. E. C. Wagner, W. H. Millett (1939). "Benzimidazole". Organic Syntheses . 19: 12. doi:10.15227/orgsyn.019.0012.
  4. Robert A. Smiley "Phenylene- and Toluenediamines" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi : 10.1002/14356007.a19_405
  5. H. A. Barker; R. D. Smyth; H. Weissbach; J. I. Toohey; J. N. Ladd & 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. doi: 10.1016/S0021-9258(18)69550-X . PMID   13796809.
  6. R. Jackstell; A. Frisch; M. Beller; D. Rottger; M. Malaun; 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.
  7. H. V. Huynh; J. H. H. Ho; T. C. Neo; 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.
  8. Taylor, R. D.; MacCoss, M.; Lawson, A. D. G. J Med Chem 2014, 57, 5845.>
  9. Horst Berneth "Methine Dyes and Pigments" in Ullmann's Encyclopedia of Industrial Chemistry, 2008, Wiley-VCH, Weinheim. doi : 10.1002/14356007.a16_487.pub2

Further reading