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Electronic and steric effects in the S N Ar substitution reactions of substituted anilines with 2,4‐dinitrophenyl 2,4,6‐trinitrophenyl ether in acetonitrile
Author(s) -
Crampton Michael R.,
Emokpae Thomas A.,
Isanbor Chukwuemeka
Publication year - 2006
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.997
Subject(s) - chemistry , steric effects , dinitrophenyl , acetonitrile , ether , substituent , medicinal chemistry , reactivity (psychology) , electronic effect , substitution reaction , alkyl , stereochemistry , organic chemistry , medicine , alternative medicine , pathology , antibody , immunology , biology
Abstract Rate measurements are reported for the reactions of 12 ring‐substituted anilines with 2,4‐dinitrophenyl 2,4,6‐trinitrophenyl ether ( 1 ) in acetonitrile. Formation of the products, the correspondingly substituted 2,4,6‐trinitrodiphenylamines, occurs without the observation of intermediates in detectable amounts by both base‐catalysed and uncatalysed pathways and Hammett ρ value were determined for these processes. The results show that although substituents at the 3‐ or 4‐positions of the anilines have only small steric effects, alkyl substituents at the 2‐position may result in considerable reductions in reactivity. These effects are more pronounced for the base‐catalysed pathway and in 2,6‐dimethylaniline the uncatalysed pathway takes all the reaction flux. In the case of the 2‐fluoro substituent the electronic effect, strong inductive electron withdrawal, is dominant over steric effects. Copyright © 2005 John Wiley & Sons, Ltd.