KCS Publications

HOME > Search > Browsing(BKCS) > Archives

Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 29, Number 1
BKCSDE 29(1)
January 20, 2008

Title	Nucleophilic Substitution Reactions of α-Bromoacetanilides with Benzylamines
Author	Keshab Kumar Adhikary, Chan Kyung Kim, Bon-Su Lee, Hai Whang Lee
Keywords	Aminolysis, α -Bromoacetanilides, Cross-interaction constants, Concave and convex Hammett plots
Abstract	Kinetic studies of the reactions of α-bromoacetanilides [YC₆H₄NHC(=O)CH₂Br] with substituted benzylamines (XC₆H₄CH₂NH₂) have been carried out in dimethyl sulfoxide at 35.0 oC. The Hammett plots for substituent (Y) variations in the substrate (log k_N vs. σY) are biphasic concave upwards/downwards with breaks at Y = 4-Cl (σY = 0.23). The Hammett coefficients ρY and the cross-interaction constant ρXY (= +0.16) are positive for σY ≤ 0.23, while the ρY values are positive/negative [ρY > 0 for X = (4-MeO and 4-Me) and ρY < 0 for X = (H, 4-Cl and 3-Cl)] and the ρXY (= ?1.51) value is negative for σY ≥ 0.23. Based on these and other results, the benzylaminolyses of α-bromoacetanilides are proposed to proceed through rate-limiting expulsion of the bromide leaving group from a zwitterionic tetrahedral intermediate, T^±, with a bridged transition state for σ Y ≤ 0.23, while the reaction proceeds through concerted mechanism with an enolate-like TS in which the nucleophile attacks the α-carbon for σ Y ≥ 0.23.
Page	191 - 0
Full Text	PDF

How to access to the WOL for The Bulletin of the Korean Chemical Society ?

The Bulletin of the Korean Chemical Society will be co-published with Wiley-VCH from 2015 towards. The online version of the Journal will thus be available on Wiley Online Library, Wiley(-VCH)'s global online platform.

KCS members can get a free online access to the Bulletin of the Korean Chemical Society in WOL.

Free Access to WOL