Aziridines chemical properties

Fused aziridines are interesting compounds owing to the fact that the strained three-membered ring can easily open and cause dipolar cycloaddition reactions as well as their photochromic properties. Therefore, most of this chapter covers the chemical and photochemical properties of bi- and tricyclic aziridines. Some properties of aziridinyl ketones are also reviewed, in particular, reactions leading to aziridinyl anils. 

The chemical properties of bi- and tricyclic aziridines are determined, first of all, by the presence of the sterically strained three-membered cycle as well as the two nitrogen atoms, which are basic centers. The most interesting reactions are the processes involving the carbon-carbon single bond cleavage of the aziridine cycle which will be considered later. 

Most of the chemical properties of fused aziridines described in the literature are concerned with cycloaddition reactions. For example, it was shown in one of the first works [93] that refluxing azirenoimidazole 72 with different compounds containing multiple C-C bonds in / interaction with diethyl acetylene dicarboxylate 116, diethyl fumarate 118 or 1,4-diarylbut-2-ene-l,4-diones 120 gives rise to the cycloadducts 117,119 and 121, respectively... 

Chemical properties of dihydroazirenoquinoxalines were studied in [106] and it was shown that these compounds react in numerous cycloadditions via cleavage of the C-C bond of the aziridine cycle as well. 

Synonyms Azirane Aziridine Chemical Formula CHjCHjNH (ii) Observable Characteristics — Physical State (as slufqted) Liquid Color Colorless Odor Fishy ammoniacal (iii) Physical and Chemical Properties —... 

The antitumor activity displayed by the mitosanes and many synthetic aziridines stems from their ability to act as alkylating agents which chemically modify (crosslink) DNA. For this reason, a large number have been screened for antitumor activity, the mechanism of which has been the subject of considerable research effort <75CJC289l). An excellent account of the broad spectrum of biological properties of a multitude of compounds containing the aziridinyl moiety has been published [Pg.93]

Capriati et carried out a B3LYP-DFT/6-311 +- -study of a series of N-H, A-methyl, and A-propyl aziridines and their C-lithium derivatives in order to explore their configurations as well as their and C NMR properties. The Li chemical shifts are not useful probes due to their small range of variation. They calculated /( Li, C) coupling constants and compared them with their measured constants. The experimental V(Li, C) constants were about one third of the calculated ones. The fact that experimental /(Li, C) constants are smaller than the calculated ones is well known.Capriati et therefore calculated the /(Li, C) for methyl lithium. The measured /(Li, Q coupling constant of methyl lithium was 15 Hz in THF, Et20, and EtsN, while the computed /(Li, C) constant was 102.5 Hz in vacuum. They studied the solvent effects on the /(Li, C) for CHsLi using the PCM method. The computed /(Li, C) for CHaLi decreased in solvents 79.0 Hz in toluene and 67.2 Hz in THF. 

Pdymerizations conducted so far have produced polymer coatii wifii a wi range of chemical and mechanical properties vtdiidi could be used to modify the carbon fiber-polymer matrix interphase of comptmt Helmed from fibers trrated by electropolymerization. A flexible polymer interphase could be introduced using systems such as methyl acrylate or VTBN, while stiffness could be adueved by using the styrene or styrene-acrylonitrile systems. Methyl methacrylate and styrene monomers would be expected to yield linear uncrosslinked polymer coatings while monomers which are multifunctional such as A,A -methylenebisacryiamide or multifunctional aziridines would be expected to crosslink in the systems they were used in. 

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