The Control of the Nitrogen Inversion in Alkyl-Substituted Diaziridines

✍ Scribed by O. Trapp; V. Schurig; R. G. Kostyanovsky

• Publisher: John Wiley and Sons
• Year: 2004
• Tongue: English
• Weight: 182 KB
• Volume: 10
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200305494

✦ Synopsis

For the first time the nitrogen inversion barriers in 3,3-unsubstituted trans-diaziridines, such as 1,2-di-tert-butyldiaziridine (1) and 1,2-di-n-butyldiaziridine (2) were determined. Enantioselective stopped-flow multidimensional gas chromatography was used to investigate the enantiomerization barrier of 1 between 126.2 and 171.0 degrees C (DeltaG ++ gas (150.7 degrees C) = 135.8+/-0.2 kJ mol(-1), DeltaH++ gas = 116.1+/-2.5 kJ mol(-1), DeltaS ++ gas == -46+/-2 J K(-1) mol(-1)). The separation of the enantiomers has been achieved in presence of the chiral stationary phase (CSP) Chirasil-beta-Dex with a high separation factor (alpha = 1.44 at 80 degrees C). In a complementary approach, the enantiomerization barriers of 1,2-di-tert-butyldiaziridine (1), 1,2-di-n-butyldiaziridine (2), 1-n-butyl-3,3-dimethyldiaziridine (3), and 1,2,3,3-tetramethyldiaziridine (4) were determined for comparison by enantioselective dynamic chromatography (DGC) and computer simulation of the dynamic elution profiles. The enantiomerization barrier of 2 was shown to be the highest among the nonsterically hindered diaziridines studied so far, whereas 1 exhibited the highest value found for strained nitrogen-containing rings, that is, aziridines, diaziridines and oxaziridines.