Aziridines are useful intermediates in organic chemistry due to their highly strained ring systems which allow for a wide range of reactivity.
It is known that aziridines are not reactive towards nucleophilic compounds unless the nitrogen has been quatemized, protonated or has formed a Lewis acid adduct.
Even though aziridines
are reactive compounds, the conditions for the nucleophile to attack on the aziridine
ring are not conducive until the water leaves, and therefore it takes some time for the crosslink density to gain optimal strength which was reflected in the performance of the coatings during MEK double rubs and pencil hardness tests.
Carboxyl functional resins will also react with aziridines
They also cover nucleic substitution at aliphatic carbon, synthesis of epoxides and aziridines
, the protonation of enolates and kinetic resolution of racemic alcohols and amines.
The latest patent extends coverage to use of compounds that include chemical structures known as aziridines
A recent example is the rhodium or cobalt-catalyzed carbonyl insertion and ring expansion of heterocycles, including aziridines
, to [Beta]-lactams.
and carbodiimides react with carboxyl groups present in most water-based acrylics and urethanes, while isocyanates typically require hydroxyl-functionality to maximize their benefits.
In practice, it might prove difficult if not impossible to effect such a polymerization, as azetidines (4-member ring compounds) are much less prone to polymerization than are aziridines
His group has developed new approaches to nitrogen heterocycles of biological significance, including indoles, aziridines
1-10) A number of crosslinkers have been employed for latex coatings, including amino resins, isocyanates, carbodiimides, aziridines
, oxazolines, and aromatic epoxides.
84) "Polyfunctional Aziridines
," Cordova Chemical Co.