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AM1 studies on the acid hydrolysis of acetamide
Author(s) -
Lee Ikchoon,
Kim Chang Kon,
Lee BonSu
Publication year - 1990
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610030608
Subject(s) - acetamide , chemistry , mndo , hydrolysis , protonation , molecule , computational chemistry , ab initio , activation energy , reaction mechanism , organic chemistry , catalysis , ion
The A2 hydrolysis of acetamide was investigated using the AM1 method and the results were compared with those of MNDO. The two methods agree in the general mechanism but differ in detail; MNDO assigns an unduly high energy for a complex with long bonds in contrast to AM1 and ab initio (at the 3–21G and 6–31G levels) methods, which predict a stable structure for such a complex. Inclusion of solvate water molecules has the effect of lowering activation barriers in general. An increase in the number of solving molecules up to four results in narrowing of the activation energy gap between the two rate determining steps of the A2 hydrolysis of the N ‐ and O ‐protonated acetamide, but no reversal of the relative order of the barrier occurs; the A2 hydrolysis proceeding through the less stable N ‐protonated tautometer is therefore likely to remain as a major reaction path in solution‐phase reactions, in agreement with experimental results.