1,3-diaxial repulsion vs. pi-delocalization in the 7-Amino-2,4-diazabicyclo[3.3.1]nonan-3-one skeleton

Citation
M. Weber et al., 1,3-diaxial repulsion vs. pi-delocalization in the 7-Amino-2,4-diazabicyclo[3.3.1]nonan-3-one skeleton, HELV CHIM A, 84(3), 2001, pp. 571-578
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis",Chemistry
Journal title
HELVETICA CHIMICA ACTA
ISSN journal
0018-019X → ACNP
Volume
84
Issue
3
Year of publication
2001
Pages
571 - 578
Database
ISI
SICI code
0018-019X(2001)84:3<571:1RVPIT>2.0.ZU;2-U
Abstract
(1R.5S,6S.8R)-6,8,9-Trihydroxy-3-oxo-2,4-diazabicyclo[3.3.1]nonan-7-ammoniu m chloride hydrate(3Cl .H2O)and(1R.5S,6S.8R)-7-amino-6,8,9-trihydroxy2,4-di azabicyclo[3.3.1]nonan-3-one (4) have been prepared. and their crystal stru ctures have been determined from single-crystal X-ray diffraction data. Bot h compounds consist of a bicyclic skeleton with the three N-atoms in an all -cis-1,3,5-triaxial arrangement. Considerable repulsion between these axial N-atoms is indicated by a significant distortion of the: two cyclohexane c hairs and by increased N...N distances. The lone pair of the free amino gro up of 4 is involved in intermolecular H-bonding and is turned away from the adjacent carbonyl C-atom of the urea moiety. The structural properties tog ether with the observed reactivity do not provide any evidence for an intra molecular donor-acceptor interaction between the carbonyl C- and the amine N-atom.