Kinetic and equilibrium studies of σ-adduct formation and nucleophilic substitution in the reactions of 2-phenoxy-3, 5-dinitropyridine and 2-ethoxy-3, 5-dinitropyridine …

MR Crampton, TA Emokpae, JAK Howard…

Index: Crampton, Michael R.; Emokpae, Thomas A.; Howard, Judith A.K.; Isanbor, Chukwuemeka; Mondal, Raju Organic and Biomolecular Chemistry, 2003 , vol. 1, # 6 p. 1004 - 1011

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Citation Number: 24

Abstract

The reactions of aliphatic amines with 2-phenoxy-3, 5-dinitropyridine, 4, and 2-ethoxy-3, 5- dinitropyridine, 5, in DMSO result in the rapid reversible formation of anionic σ-adducts at the 6-position. Kinetic studies show that proton transfer from the initially formed zwitterions to base may be rate-limiting. Slower reactions result, except in the case of 5 and piperidine, in displacement of the 2-substitutent via intermediates which have lower thermodynamic ...