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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 18, Number 4
BKCSDE 18(4)
April 20, 1997 

Kinetic Studies on the Nucleophilic Addition of Thiophenol Derivatives to 4'-[N-(9-Acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide
Tae Rin Kim, Dong In Chung, Sang Yong Pyun
The rate constants for the nucleophilic addition of thiophenol derivatives (p-OCH3, H, p-CH3, m-CH3, p-Br and p-NO2) to 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-met hoxyquinonediimide (AMQD) were determined by ultraviolet spectrophotometer in water at 5 ℃, and rate equations which can be applied over a wide pH range were obtained. On the basis of pH-rate profile, Bronsted plot, adduct analysis, general base catalysis and substituent effect, a plausible mechanism of this addition reaction was proposed: Below pH 2.5, the reaction proceeded by the addition of thiophenol molecule to 6'-position of quinonoid after protonation at the acridinyl nitrogen. Above pH 6.2, the addition of sulfide anion to 6'-position of quinonoid was rate controlling. However, in the range of pH 3.0-6.0, these two reactions occured competively.
374 - 379
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