Posted by Admin on September, 12, 2020
Aziridine is an organic compound that contains the functional group of aziridine, which has three members – an amine group and a pair of methylene bridges, to form a heterocycle. Here the parent compound remains ethylene imine or aziridine which has its molecular formula, C2H5N.
Structure of Aziridine:
The angles of its bonds are roughly around 60 degrees in aziridine, which is significantly less than the natural bond of hydrocarbon which has its bond angle around 109 degrees. This makes angle strain happen which accelerates the barricade towards nitrogen inversion.
Synthesis of Aziridine:
Various aziridination or syntheses of aziridine are available.
• Cyclization of amino alcohols and haloamines –
For generating aziridine, a functional group of amine transfers the head-to-head halide in a substitution reaction of intramolecular nucleophilic. The similar reactivity has the amino alcohols but for worthy use of hydroxyl group, it needs to be converted first into a worthy leaving group. The cyclization method for amino alcohol and haloamine is known as Wenker synthesis and Gabriel ethylenimine respectively.
• Nitrene addition –
It is a firm method to make the synthesis of aziridines and it is done by adding nitrene to alkenes. For generating nitrenes, both azide thermolysis and photolysis are suitable ways.
• Triazoline decomposition –
Triazolines photolysis or a thermal treatment ejects nitrogen to produce an aziridine. The generation of triazolines can be done by alkenes cycloaddition with an azide.
• From epoxides –
In two ways, aziridines can be synthesized from epoxides. 1) Ring opening reaction with sodium azide and epoxide -> with triphenylphosphine, azide’s organic reduction -> nitrogen gas expulsion. 2) Ring opening reaction with amines and epoxide -> Mitsunobu reaction for ring closing.
• From oximes –
The reaction of Grignard reagents with oxides is called as Hoch-Campbell aziridine synthesis.
• From alkines –
A new process was produced in 2014 for developing aziridines by making reactions with DPH and a tetra, tri, di, or monosubstituted alkene, and all these things were performed by homogeneous catalysis of rhodium. This method is extremely profitable and has a simple operation.
Reactions of Aziridines:
Two of the major reactions performed by aziridine manufacturers are -
Nucleophilic ring opening
Due to its ring strain, with various nucleophiles in the ring opening reactions, aziridine acts as reactive substrates. Aminolysis and alcoholysis are mainly the inverse responses of cyclizations.
1,3 dipole formation
In a ring opening photochemical or electrocyclic thermal reaction, electron withdrawing groups and a few specific N-substituted azirines produce azomethine ylides, which can be confined in a 1,3 dipolar cycloaddition with an appropriate dipolarophile.
A specific aziridine compound's toxicology depends on its activity and structure.
Exposure – direct contact and inhalation are contact routes. Even according to some reports, gloves usage may not prevent the infusion of aziridine. So, it is important for the users to always check the breakthrough time for permeation of the gloves, and at the time of degloving, for avoiding contamination it is important to pay honorable attention to it.
People, who work with aziridines are advised to wear special kind of respirators which have filtering effects for resisting fumes, mists, and dust. For better use and safety, users should purchase from the recognized aziridine manufacturers only.
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