929601-52-5Relevant academic research and scientific papers
Synthesis, configuration, and 15N NMR spectra of iminoaziridines. Synthons equivalent to three components of the ugi reaction
Quast, Helmut,Aldenkortt, Sven,Freudenreich, Bernd,Schaefer, Peter,Hagedorn, Manfred,Lehmann, Jens,Banert, Klaus
, p. 1659 - 1666 (2007/10/03)
Monocyclic iminoaziridines and exo-endo diastereomers of spirocyclic iminoaziridines that are derived from norbornane are prepared in batches of up to 10 g to foster applications as building blocks in syntheses. N,N′-Disubstituted α-haloamidines, which are readily available in two steps from N-substituted α-halocarboxamides, are 1,3- dehydrohalogenated by strong bases such as alkali-metal hydrides or tert-butoxides to afford distillable oils or low-melting solids, which consist of slowly interconverting E-Z diastereomers of the title compounds. The scope and limitations are outlined for this reaction. The configurations E and Z that were assigned on the basis of homoallylic 1H-1H coupling and asymmetric solvent-induced shifts required that, in 13C NMR spectra, the observed γ-effects of substitutents at the imino nitrogens were deshielding, contrary to the well-known shielding γ-effects in all other types of C=N compounds. However, an NOE NMR study demonstrated unequivocally that the previous assignments are correct and hence the observed γ-effects actually deshielding. The ranges of 15N NMR chemical shifts span more than 60 ppm. Neither the β- nor the γ-effects of substituents on both types of nitrogen follow a uniform increment pattern.
