Diaziridines stability

S.08.2.3.1 NMR investigations on oxaziridines and diaziridines, configurational stability at nitrogen... 

NMR investigations in the diaziridine field also led to the problem of inversion stability at nitrogen. Further investigations paralleled those of oxaziridines NMR investigation in solution (67CB1178) was followed by preparative separation of invertomers and finally preparation of optically active individuals. 

The diaziridine ring exhibits a surprising stability towards strong oxidizing agents. Diaziridines unsubstituted at both N atoms can be transformed into diazirines by dichromate in acidic solution or by chlorine (Section 5.08.4.3). Radical attack by decomposing peroxide converts (136) to the diaziridinyl radical (137), as evidenced by ESR spectroscopy (76TL4205). 

Diaziridine, 3-benzyl-1,3-dimethyl-inversion, 7, 7 Diaziridine, 1,2-dialkyl-reaction with iodides, 7, 217 thermal decomposition, 7, 217 Diaziridine, dibenzoyl-rearrangement, 7, 214 Diaziridine, 3,3-dimethyl-Raman spectra, 7, 202 Diaziridine, fluoro-synthesis, 7, 232 Diaziridines acylation, 7, 213 from azomethines, 7, 231 calculations, 7, 198 from chloramine, 7, 230 cycloaddition reactions, 7, 28 electron diffraction, 7, 19 199 c/s-fused NMR, 7, 201 hydrolysis, 7, 216 inversion stability, 7, 200... 

In their thermal stability the diaziridines approximate to the oxaziranes. As with most oxaziranes, they are stable at 100° C for short periods they are decomposed by heating at 200°C 1,2-di-n-butyl-3-ri-propyldiaziridine thus eliminates butylamine. The thermal decomposition has not yet been investigated in detail. Similarly no information is available on the reaction of radical reagents on diaziridines. 

Thermolysis of 6-substituted l,5-diazabicyclo[3.1.0]hexanes 326, easily available from 325, leads to a diaziridine ring opening and to the intermediate formation of labile azomethine imines 327. These compounds can be stabilized by a proton shift to form 1-substituted 2-pyrazolines 328. However, when the thermolysis is carried out in the presence of a 1,3-dipolarophile, the corresponding products of dipolar cycloaddition can be obtained. For example, iV-arylmaleimides provide mixtures of the major trans- and minor air-products 329 and 330, respectively (Scheme 47) C1999RJO110, 2001RJ0841, 2003RJ01338, 2004RJ067>. 

Some aldehyde-derived diaziridines are unstable and hamper the Schmitz synthesis of the corresponding diazirines <1975J(P2)686>. A one-pot derivative of the standard Schmitz reaction has been developed to circumvent such problems, in which an intermediate diaziridine is stabilized by a trimethylsilyl group <2000TL795>. Treatment of the aldehydes 68a-c with LiHMDS, then HOSA, gave the silicon-stabilized diazirines 69a-c. In situ oxidation with f-butyl hypochlorite generated the diazirines 70a-c in moderate yields (Scheme 24). 

Structures and Stabilities of Three-Membered Rings 16. CN2H4 Diaziridine (17)... 

Experimental methods have been remarkably useful especially in three-membered heterocycles. At the time of discovery of these compounds, mainly chemical methods were available to prove their structures, which yielded erroneous results. Experimental methods such as x-ray analysis, H NMR, 13C NMR, IR/Raman, UV, PES, and MS provided data on molecular geometry, bond connectivity, absolute configuration of the molecule, and configurational stability at nitrogen. Experimental data corrected and confirmed the chemical structures of title compounds. Complete experimental data from earlier studies on some diazirines and diaziridines, are provided and discussed with illustrations <84CHEC-I(7)195>. 

Diaziridines differ from simple amines and hydrazines radically in many properties. First of all, the nitrogen atoms of diaziridines feature high pyramidal stability. The inversion of nitrogen atoms in diaziridine rings has been studied actively since 1967 <67CB1778>. Optically active diaziridines with an asymmetric nitrogen atom have been studied since 1974 <74izvi67i>. In the molecules of... 

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