الفهرس 
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Abstract
The kinetic observations for the reactions of isatin derivatives with pip and OH‒ reveal that electron withdrawing substituent enhances the reactivity while electron releasing substituent inhibit the rate and the rate of ring opening process of isatins follows the order: 7-chloro > 7-bromo > H > 5-Chloro > 5-bromo> 5-CH3 > 7-CH3. The trend may be attributed to the inductive. While the greater effect of 7-substituent than 5-substitutent is presumably due to proximity effect.
The correlation of kN values for the reaction of isatin derivatives with both pip and OH‒ with Hammett and Taft’s substituent constants at various temperatures (20-40oC) showed scattered points with poor correlation coefficients. The application of Taft’s equation to correlate *-Taft values for 7-substituents (ortho-substituent) with log kN values with removing 5-substituents gave good straight lines with = 0.52-0.48, r =1.0-0.99. Thus, σ-Hammett for 5-substituents and σ*-Taft’s for 7-substitutents are not suitable for application in the reactions of isatin derivatives with pip and OH‒.
Accordingly, o-Taft’s constant for substituted phenyl ring are used. These values are the more suitable with our system in which the substituent is far from the reaction center and attached to benzene ring. Following the procedure recommended by Taft and Lewis, the unknown substituents constants are then evaluated from the relationship. It is found that a regression line is fitted to the log kN against and ocalc for 5- and 7-substituted isatins respectively. The plot shows a linear straight line with positive slope with values ranged between 1.86-2.01 and 1.04-0.98 for the reactions of isatin derivatives with pip and OH‒ respectively depending on the temperature.