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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 11, Number 3
BKCSDE 11(3)
March 20, 1990 

 
Title
Theoretical Studies on the A2 Hydrolysis of Methyl Acetimidate
Author
Ikchoon Lee*, Chang Kon Kim, Bon-Su Lee
Keywords
Abstract
Various mechanistic aspects of the A2 hydrolysis of methyl acetimidate were explored using the MNDO method. As in thecorresponding reactions of acetamide and methyl carbamate, a proton transfer pre-equilibrium exists between the N-protonated and the O-protonated tautomers, and the subsequent hydrolysis proceeds from the more stable N-protonated form. Of the two reaction pathways, the AAL2 path is favored in the gas phase and in concentrated acid solutions, whereas the AAC2 path is favored in less acidic solutions with a stable cationic tetrahedral intermediate formed in the rate determining step. Negative charge development on the alkoxy oxygen in the transition state suggested a rate increase with the increase in the electron withdrawing power of the alkoxy group. Calculations on the reaction processes with AM1 indicated that MNDO is more reliable in this type of work, although AM1 is better than MNDO in reproducing hydrogen bonds.
Page
194 - 200
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