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Skeletal formula of imidazoline
Ball-and-stick model of the imidazoline molecule
IUPAC name
504-75-6 YesY
ChEBI CHEBI:53094 YesY
ChemSpider 61464 YesY
Jmol 3D model Interactive image
PubChem 68156
Molar mass 70.10 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

2-Imidazoline (dihydroimidazoles) is one of three isomers of the nitrogen-containing heterocycle with formula C3H6N2, derived from imidazole. The 2-imidazolines are the most common imidazolines commercially, as the ring exists in some natural products and some pharmaceuticals. They also have been examined in the context of organic synthesis, coordination chemistry, and homogeneous catalysis.[1]

Biological role[edit]

Many imidazolines are biologically active.[2] Most bio-active derivatives bear a substituent (aryl or alkyl group) on the carbon between the nitrogen centers. Some generic names include oxymetazoline, xylometazoline, tetrahydrozoline, and naphazoline.

Synthesis of Imidazoline[edit]

A variety of routes exist for the synthesis of imidazolines,[1][3] with the most common methods involving the condensation of 1,2-diamines with nitriles or esters. The nitrile based route is effective for both alkyl and aryl nitriles and requires high temperatures or acid catalysis.

Synthesis of imidazolines from nitrile and from ester precursors.

Imidazoline in Natural Products[edit]

Imidazoline has been found in various natural products. Natural molecules topsentin D and spongotine B were discovered in several marine sponges. These metabolites have received considerable attention because of their potent properties such as antitumor, antiviral, and anti-inflammatory activities.[4]

Pharmaceutical Applications[edit]

2-imidazolines have been investigated as antihyperglycemic, anti-inflammatory, antihypertensive, antihypercholesterolemic, and antidepressant reagents.[1][5] The imidazoline-containing drug clonidine is used alone or in combination with other medications to treat high blood pressure. It is also used in the treatment of dysmenorrhea, hypertensive crisis, Tourette's syndrome and attention deficit hyperactivity disorder (ADHD).[6]

Homogeneous Catalysis[edit]

As a structural analogue of 2-oxazolines, 2-imidazolines have been developed as ligands in coordination chemistry. The substitutions on the nitrogen atom in the imidazoline ring provide opportunities for fine-tuning the electronic and steric properties. Some of the complexes function as catalysts for Suzuki–Miyaura couplings, Mizoroki–Heck reactions, Diels–Alder reactions, asymmetric allylic substitution, [3,3] sigmatropic rearrangement, Henry reactions, etc.[1]

Industrial Applications[edit]

Imidazoline derivatives have extensive applications in surfactant in small proportions for improving detergent qualities for various purposes (fabric softeners, hair and fabric conditioning).[7]

Imidazolines as Precursors of Imidazoles[edit]

Imidazoles can be prepared from dehydrogenation of imidazolines.[8]

Dehydrogenation of imidazoline.png

See also[edit]


  1. ^ a b c d Liu, H.; Du, D.-M. (2009). "Recent Advances in the Synthesis of 2-Imidazolines and Their Applications in Homogeneous Catalysis". Adv. Synth. Catal. 351: 489–519. doi:10.1002/adsc.200800797. 
  2. ^ N. MacInnes and S. Duty (2004). "Locomotor effects of imidazoline I2-site-specific ligands and monoamine oxidase inhibitors in rats with a unilateral 6-hydroxydopamine lesion of the nigrostriatal pathway". Br J Pharmacol. 143 (8): 952–959. doi:10.1038/sj.bjp.0706019. PMC 1575965free to read. PMID 15545290. 
  3. ^ David Crouch, R. (March 2009). "Synthetic routes toward 2-substituted 2-imidazolines". Tetrahedron. 65 (12): 2387–2397. doi:10.1016/j.tet.2008.12.022. 
  4. ^ Guinchard, X.; Valle; Denis, J. N. (2007). "Total Synthesis of Marine Sponge Bis(indole) Alkaloids of the Topsentin Class". J. Org. Chem. 72 (10): 3972–3975. doi:10.1021/jo070286r. 
  5. ^ Dardonville, C.; Rozas, I. (2004). "Imidazoline binding sites and their ligands: An overview of the different chemical structures". Med. Res. Rev. 24: 639–661. doi:10.1002/med.20007. 
  6. ^ "Clonidine", Pubmed Health, http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000623/
  7. ^ Tyagi, R.; Tyagi, V. K.; Pandey, S. K. (2007). "Imidazoline and its derivatives: an overview". J. Oleo. Sci. 56: 211–222. doi:10.5650/jos.56.21. 
  8. ^ Ishihara, M.; Togo, H. (2006). "An Efficient Preparation of 2-Imidazolines and Imidazoles from Aldehydes with Molecular Iodine and (Diacetoxyiodo)benzene". Synlett: 227–230. doi:10.1055/s-2005-923604.