Anilinolysis of nitro-substituted diphenyl ethers in acetonitrile: The effect of some ortho-substituents on the mechanism of SNAr reactions

✍ Scribed by Chukwuemeka Isanbor; Thomas A. Emokpae

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 332 KB
• Volume: 42
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20457

✦ Synopsis

Abstract

Rate data are reported for the reactions of a series of X‐phenyl 2,4,6‐trinitrophenyl ethers 1a–e[X = H, 4‐NO~2~, 2‐NO~2~, 2,4‐(NO~2~)~2~, or 2,6‐(NO~2~)~2~] with substituted anilines 2a–e [Y = H, 2‐CH~3~, 2,4‐(CH~3~)~2~, 2,6‐(CH~3~)~2~, or N‐CH~3~] in acetonitrile as solvent. For individual amine, kinetic data show that there is little steric hindrance to attack at the 1‐position of the parent molecules, even in the presence of di‐ortho substitution. With each substrate, however, there is evidence for significant steric interactions; such effects leading to rate retardation were very severe for 2,6‐dimethylaniline 2d (2,6‐(CH~3~)~2~) and N‐methylaniline 2e (Y = N‐CH~3~), the deactivating effect of N‐CH~3~ in most cases is slightly higher than that of 2,6‐(CH~3~)~2~. However, the reactions with 2e are base catalyzed whereas those of 2d are not. The corresponding reactions with aniline 2a (Y = H) and mono‐ortho methyl‐substituted aniline 2b (Y = CH~3~) are wholly base catalyzed. Only with the dinitro substrates, an uncatalyzed reaction is observed and when X = 2,6‐(NO~2~)~2~ this pathway takes all the reaction flux. A rationale is provided for the dichotomy of amine effects observed in this investigation. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 37–49, 2010