Structural features of aliphatic N-nitrosamines of 7-azabicyclo[2.2.1]heptanes that facilitate N-NO bond cleavage.
N-Nitrosamines can be considered as potential nitric oxide (NO)/nitrosonium ion (NO(+)) donors. However, the relation of the structures of N-nitrosamines, in particular of aliphatic N-nitrosamines, to the characteristics of release of NO or NO(+) remains unclear. Here we show that aliphatic N-nitrosoamines of 7-azabicyclo[2.2.1]heptanes can undergo heterolytic N-NO bond cleavage. On the basis of the observation of reduced rotational barriers of the N-NO bonds in solution and nitrogen-pyramidal structures of the N-nitroso group in the solid state, we postulate that N-NO bond cleavage of N-nitrosamines is enhanced by a reduction of the resonance in the N-NO group. Computational studies suggest that these structural features of the N-nitrosamines of 7-azabicyclo[2.2.1]heptane are derived from angle strain imposed on the CNC angles.
Ohwada
T
T
Contribution from the Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
Miura
M
M
Tanaka
H
H
Sakamoto
S
S
Yamaguchi
K
K
Ikeda
H
H
Inagaki
S
S
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008968:Molecular Conformation; D015394:Molecular Structure; D020030:Nitric Oxide Donors / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D009602:Nitrosamines / Q000737:chemistry*; D013329:Structure-Activity Relationship
D019086:Bridged Bicyclo Compounds, Heterocyclic; D020030:Nitric Oxide Donors; D009602:Nitrosamines; D009584:Nitrogen