Triaziridine 7. Mitteilung. Stabile pyramidale Konfigurationen an den Stickstoff-Atomen von Dialkyl-und Trialkyl-triaziridinen
✍ Scribed by Hans Hilpert; Lienhard Hoesch; André S. Dreiding
- Publisher
- John Wiley and Sons
- Year
- 1987
- Tongue
- German
- Weight
- 495 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Stable Pyramidal Configurations at the Nitrogen Atoms of Dialkyl-and Trialkyl-triaziridines
Stereochemical features of the recently synthesizcd nine samples of di-and trialkyl-triaziridines, namely the 1 ,kyclopentylen-(series a) and the two stereoisomcrs or the diisopropyl derivatives (series h and c), containing as the third substituent an H-atom (2), a CH, group (3) or a CHzOH group (4), were elaborated on the basis of the 'H-, ',C-, and "N-NMR spectra. The three N-atoms of the saturated N,-homocycle were found to be stable to pyramidal invcrsion in all cases. According to their NMR spectra, 2 4 of the series a and b possess twofold symmetry (CJ, while 2 4 of series c art: asymmetric. Thus, series c has the tran.7-configuration at N(2)/N(3) and, consequently, the ci,wxnliguration at N(I)/N(2), while series a and b have the &-configuration at N(2)/N(3) and -since the all-cis-arrangement is excluded ~ the truns-configuration at N(I)/N(2). The asymmctry of the frans-configurated 2c turned into twofold symmctry (C2), when a little CF,COOH was added. The 'Hand "C-NMR data of series h and c of our alkyl-triaziridines exhibit a shielding effect, according to which there are two types ofi-Pr groups, i-Pr(a) and i-Pr(b). They differ in the NMR signals of the Hand the C-atoms of their CH groups: the H-atoms of i-Pr(a) are more deshielded by 0.75-1. I 1 ppm and its C-atoms are more shielded by 10.0-16.0 ppm as compared to the corresponding atoms of i-Pi-@). i-Pr(a) is cis (on thc N3-homocycle) to a large substituent (such as i-Pr, Me, CH,OH) and to a lone pair, while i-Pr(b) is cis only to a small (H) or to no substituent and to one or two lone pairs. An analogous effect appears in the NMR signals ofthe CH, and CH,OH groups at N( 1) of 3 and 4 in the series h and c.