Proceedings - Interdisciplinary Center for Nanotoxicity

104
Conference on Current Trends in Computational Chemistry 2009
Mechanism of Aryl Azide Addition to Substituted
Norbornene Imides: Effect of Acid Catalysis to the Reaction
Pathways
T.Petrova, a,b I. Borisenko b, S.Okovytyy, a,b L. Gorb, a I.Tarabara, b J.Leszczynski a
a Interdisciplinary Center forNanotoxicity, Department of Chemistry and Biochemistry,
Jackson State University, Jackson, MS 39217, USA
b Department of Organic Chemistry, Dnepropetrovsk National University, Dnepropetrovsk
49625, Ukraine
Development of synthetic approaches and theoretical investigation of mechanisms for
reactions of new biologically active nitrogen containing norbornene derivatives due to
transformation of different reaction centers of molecules is one of important problems of
organic chemistry for heterocyclic compounds. For example, aziridination of carbon double
bond (C=C) in some norbornene compounds results in generation of polycyclic triazolines
and/or aziridines possessing antineoplastic and antiviral acitivities. Understanding the
mechanisms of actual chemical transformations of this type of compounds is a great challenge
and source of inspiration for both experimentalists and theoreticians.
According to available experimental data the addition of aryl azide (p‐NO2C6H4N3) to
various norbornene imide derivatives (1,2) resulted in exo‐triazoline formation. Unexpectedly,
reaction of imide bearing the acid substituent at the nitrogen atom (3) with aryl azide led to the
formation of azidine polycyclic system as the major product. In order to explain the nature of
transformations a quantum‐chemical investigation of possible reaction pathways for the aryl
azide addition to norbornene imides (1‐3) and catalytic effect of carboxylic acid in the course of
reaction has been performed.
O
O
N
C
O
R
p-NO 2C 6H 4N 3
CHCl 3
R = -OCH 3 (1), -NHCH 2C 6H 5 (2)
3
O
O
N
COOH
p-NO 2C 6H 4N 3
CHCl 3
O 2N
O 2N
N
N
N
N
O
O
N
C
O
O
O
N
R
COOH
All calculations have been performed at the B3LYP/6‐31+G(d) level of theory in the gas
phase and in the presence of chloroform as solvent (Polarizable Continuum Model). The
addition of azides to bicyclic imides affords either exo‐triazolines or exo‐aziridine depending on
nature of imide substuituent. The steric bulk of the azide does not appear to play a significant