abs

학술발표회초록보기

초록문의 abstract@kcsnet.or.kr

결제문의 member@kcsnet.or.kr

현재 가능한 작업은 아래와 같습니다.
  • 03월 04일 13시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

Effect of Substituent on Regioselectivity and Reaction Mechanism in Aminolysis of 2,4-Dinitrophenyl X-Substituted Benzenesulfonates

등록일
2005년 2월 17일 15시 47분 18초
접수번호
0991
발표코드
24P235포 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
발표시간
토 <발표Ⅲ>
발표형식
포스터
발표분야
유기화학
저자 및
공동저자
전상은, 엄익환, 석진아
이화여자대학교,
We report on a kinetic study for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzensulfonates (X = 4-MeO, 1a and X = 4-NO2, 1c) with a series of primary amines in 80 mol % H2O/20 mol % DMSO at 25.0°C. The reactions proceed through S-O and C-O bond fission pathways competitively. The fraction of the S-O bond fission increases as the attaching amine becomes more basic and the substituent X changes from 4-MeO to 4-NO2, indicating that the regioselectivity is governed by the electronic nature of the substituent X as well as the basicity of amines. The S–O bond fission has been suggested to proceed through an addition intermediate with a change in the rate-determining step (RDS) at pKa° = 8.9 ± 0.1. The electronic nature of the substituent X influences kNS-O and k1 values, but not the k2/k–1 ratios and the pKa° value significantly. Stabilization of the ground-state (GS) through resonance interaction between the electron donating substituent and the electrophilic center has been suggested to be responsible for the decreased reactivity of 1a compared to 1c.

상단으로