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Double inversion of the secondary nitrogens in cis ‐Diaziridinocyclopentane
Author(s) -
Majchrzak Michał W.,
Kotełko Antoni,
Lambert Joseph B.
Publication year - 1983
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/omr.1270211114
Subject(s) - chemistry , nitrogen inversion , aziridine , azide , intramolecular force , amine gas treating , molecule , sodium azide , stereochemistry , medicinal chemistry , azetidine , nitrogen , crystallography , ring (chemistry) , organic chemistry
Abstract 1α,2α,4α,6α,‐3,7‐Diazatricyclo[4.1.0.0 2,4 ]heptane ( cis ‐diaziridinocyclopentane) (1) has been prepared from the analogous cis ‐diepoxycyclopentane. Ring opening of the diepoxide with sodium azide produced a pair of regioisomeric azido alcohols. Tosylation and treatment with lithium aluminum hydride produced 1. The dibenzoyl derivative possessed the di‐ exo stereochemistry for the tertiary aziridine nitrogens. The 1 H spectrum of 1 was temperature dependent. Both the CH and NH resonances underwent decoalescence as the temperature was lowered. Because the rate was independent of concentration, the mechanism is probably inversion of the secondary nitrogen, the first such example to occur by the interchange of two diastereotopic, secondary (NH) amine nitrogens within the same molecule. The free energy of activation at coalescence (0 °C) was measured to be 12.8 kcal mol −1 . The unsymmetrical slow exchange of 1 is clearly consistent with the exo , endo stereochemistry for the secondary aziridine nitrogens, possibly stabilized by intramolecular attraction.