Kinetics of SNAr reactions of 1‐phenoxy‐nitrobenzenes with aliphatic amines in toluene: ring substituent and solvent effects on reaction pathways
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Date
2009-05-06
Authors
Isanbor, C.
Babatunde, A.I.
Journal Title
Journal ISSN
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Publisher
Wiley
Abstract
Rate constants are reported for the reactions of a series of 4-substituted-1-phenoxy-2,6-dinitrobenzenes 1 and
6-substituted-1-phenoxy-2,4-dinitrobenzenes 2 activated by CF3, COOCH3, CN, NO2 groups or by ring-nitrogen with
n-butylamine, pyrrolidine or piperidine in toluene. The results are compared with those reported previously for
reactions of the same substrates and nucleophiles in acetonitrile [Crampton et al., Eur. J. Org. Chem., 2006,
1222–1230]. Plots of the overall second-order rate constant, kA versus [Am] for the reactions with n-butylamine
and pyrrolidine followed a similar kinetic pattern to that obtained for the same reactions in acetonitrile whereas for
reactions with piperidine, an upward (convex) curvature is observed, an indication that a small third order term in
amine may be present. Overall reactivity is lower in toluene than in acetonitrile. Mechanisms for the overall
substitution process have been rationalised in terms of the proton transfer mechanism and cyclic transition
mechanism, for reactions involving third-order kinetics.
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Keywords
Research Subject Categories::NATURAL SCIENCES::Chemistry::Physical chemistry::Kinetics , solvent effects , substituent effects , Nucleophilic aromatic substitution , Aliphatic amines
Citation
Isanbor, C., & Babatunde, A. I. (2009). Kinetics of SNAr reactions of 1‐phenoxy‐nitrobenzenes with aliphatic amines in toluene: ring substituent and solvent effects on reaction pathways. Journal of Physical Organic Chemistry, 22(11), 1078-1085.