Aziridine is an
organic compound
Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...
consisting of the three-membered
heterocycle . It is a colorless, toxic, volatile liquid that is of significant practical interest.
Aziridine was discovered in 1888 by the chemist
Siegmund Gabriel. Its derivatives, also referred to as
aziridines, are of broader interest in medicinal chemistry.
Structure
The
bond angles in aziridine are approximately 60°, considerably less than the normal
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...
bond angle of 109.5°, which results in
angle strain as in the comparable
cyclopropane and
ethylene oxide molecules. A
banana bond model explains bonding in such compounds. Aziridine is less
basic
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...
than
acyclic aliphatic amines, with a
pKa of 7.9 for the
conjugate acid
A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid gives a proton () to a base—in other words, it is a base with a hydrogen ion added to it, as it loses a hydrogen ion in the rever ...
, due to increased
s character of the
nitrogen
Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...
free electron pair.
Angle strain in aziridine also increases the barrier to
nitrogen inversion. This barrier height permits the isolation of separate ''invertomers'', for example the
''cis'' and
''trans'' invertomers of ''N''-chloro-2-methylaziridine.
Synthesis and uses
Aziridine is produced industrially from
aminoethanol via two related routes. The Nippon Shokubai process requires an oxide catalyst and high temperatures to effect the dehydration. In the
Wenker synthesis, the aminoethanol is converted to the
sulfate ester
In organosulfur chemistry, organosulfates are a class of organic compounds sharing a common functional group with the structure . The core is a sulfate group and the R group is any Organyl group, organic residue. All organosulfates are formally ...
, which undergoes base-induced sulfate elimination. Older methods entailed amination of 1,2-dichloroethane and cyclization of 2-chloroethylamine.
[
Aziridine forms a wide variety of polymeric derivatives, known as polyethylenimines (PEI). These and related species are useful crosslinking agents and precursors for coatings.][
]
Safety
Aziridine is highly toxic with an LD50 of 14 mg (oral, rats). It is a skin irritant. As an alkylating agent, it is also a mutagen.[ It is reactive toward DNA, potentially relevant to its mutagenicity. Aziridine containing compounds also appear to be similarly dangerous.]
See also
* Binary ethylenimine, a dimeric form of aziridine
References
{{Commonscat
Functional groups
IARC Group 2B carcinogens
Aziridines
Substances discovered in the 19th century