Imidazolidine

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.

Imidazolidine
Structural formula of imidazolidine
Ball-and-stick model of imidazolidine
Names
Preferred IUPAC name
Imidazolidine[1]
Systematic IUPAC name
1,3-Diazacyclopentane
Other names
Tetrahydroimidazole
1,3-Diazolidine
Identifiers
3D model (JSmol)
ChemSpider
Properties
C3H8N2
Molar mass 72.109
Supplementary data page
Refractive index (n),
Dielectric constant (εr), etc.
Thermodynamic
data
 Phase behaviour
solid–liquid–gas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Preparation

Imidazolidines are traditionally prepared by condensation reaction of 1,2-diamines and aldehydes. Most commonly, one or both nitrogen center is substituted with an alkyl or benzyl (Bn) group:[2]

(CH2NBn)2 + PhCHO → (CH2NBn)2C(H)Ph + H2O

The first unsubstituted imidazolidine synthesis was reported in 1952.[3]

Reactions

Unsubstituted imidazolidines are often labile.[4] The rings are susceptible to hydrolysis back to the diamine and the aldehyde.[2]

Formally, removal of the two hydrogens at carbon 2 (between the two nitrogens) would yield the carbene dihydroimidazol-2-ylidene. Derivatives of the latter comprise an important class of persistent carbenes.[5]

Classified as a diamine, it is formally derived by the addition of four hydrogen atoms to imidazole. The intermediate, resulting from the addition of only two hydrogen atoms is called imidazoline (dihydroimidazole). The connection of imidazolidine to related compounds is indicated in the Figure.

Structure relationship of imidazole and its reduced derivatives.

References
  1. "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 142. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
  2. Ferm, R. J.; Riebsomer, J. L. From "The chemistry of the 2-imidazolines and imidazolidines" Chemical Reviews, 1954, 54, 593-613. doi:10.1021/cr60170a002
  3. E. D. Bergmann; E. Meeron; Y. Hirshberg; S. Pinchas (1952). "Reaction products of primary β-hydroxy-amines with carbonyl compounds. IV. Infrared and ultraviolet absorption spectra of ethylenediamine derivatives". Rec. Trav. Chim. 71 (2): 200–212. doi:10.1002/recl.19520710211.
  4. Madeleine M. Joullie; George M. J. Slusarczuk; Adrienne S. Dey; Paul B. Venuto; Ronald H. Yocum (1967). "Synthesis and properties of fluorine-containing heterocyclic compounds. IV. N,N-Unsubstituted imidazolidine". J. Org. Chem. 32 (12): 4103–4105. doi:10.1021/jo01287a100.
  5. A. J. Arduengo; H. V. R. Dias; R. L. Harlow; M. Kline (1992). "Electronic stabilization of nucleophilic carbenes". J. Am. Chem. Soc. 114 (14): 5530. doi:10.1021/ja00040a007.
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