ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 31, Number 4
JKCSEZ 31(4)
August 20, 1987 

Rate constants for the hydrolysis of para-substituted phenyl N-(p-chlorobenzoyl)chloroformimidate (Ⅰ) derivatives in 1 : 4 dioxane-water at 25℃ have been determined. Rate data, substituent effect (ρ > ρ+), product analysis and MO calculation indicate that the uncatalyzed reaction proceeds through an SN1 mechanism involving the formation of azocarbonium ion (Ⅱ) below pH 3.0, and the base-catalyzed reaction proceeds through an SN2 mechanism via transition state (Ⅲ) above pH 4.0. The relative stability of four peri planar conformational isomers were (E-ap) > (Z-ap) > (E-sp) > (Z-ap), respectively, and the most stable stereo structures shows that the Y-substituted phenyl group (C6H4-Y) occupy vertical (90°) position on the plane of the benzimidochloroformyl group in (E-ap) conformer. The nucleophilic substitution of water molecule occurs by sigma attack to the activatived azomethine carbon atom of (Ⅰ) derivatives.