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

Names
Preferred IUPAC name Imidazolidine[1]
Systematic IUPAC name 1,3-Diazacyclopentane
Other names Tetrahydroimidazole 1,3-Diazolidine
Identifiers
CAS Number	504-74-5 Y
3D model (JSmol)	Interactive image
Beilstein Reference	102462
ChEBI	CHEBI:33137
ChemSpider	396007 Y
PubChem CID	449488
UNII	AEE9PL2D22 Y
CompTox Dashboard (EPA)	DTXSID2073192
InChI InChI=1S/C3H8N2/c1-2-5-3-4-1/h4-5H,1-3H2 N Key: WRYCSMQKUKOKBP-UHFFFAOYSA-N N InChI=1/C3H8N2/c1-2-5-3-4-1/h4-5H,1-3H2 Key: WRYCSMQKUKOKBP-UHFFFAOYAC
SMILES N1CCNC1
Properties
Chemical formula	C3H8N2
Molar mass	72.109
Supplementary data page
Imidazolidine (data page)
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]

${\displaystyle {\ce {(CH2NBn)2 + PhCHO -> (CH2NBn)2C(H)Ph + H2O}}}$

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]

Related imidazole-derived heterocycles

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.