SN2 reactions at amide nitrogen - theoretical models for reactions of mutagenic N-acyloxy-N-alkoxyamides with bionucleophiles

Author(s)
Glover, Stephen
Publication Date
2001
Abstract
The reactions of N-formyloxy-N-methoxyformamide 4 with ammonia 2 and methanethiol 3 have been modeled at the AM1, HF/6-31G* and Density Functional computational levels. The reaction process is similar geometrically and electronically to classical SN2 reactions at carbon. Near-linear transition states reveal extensive charge separation and partial nitrenium ion character at the formamide nitrogen indicative of a non-synchronous process involving early stretching of the formate-formamide nitrogen bond. Activation energies, computed from pBP/DN* energies of HF/6-31G* ground state and transition state geometries, are in the range of experimental values and a strong solvation effect is predicted. Evidence for anomeric weakening of the N-formate bond by the geminal alkoxyl oxygen was obtained from a comparison of the reactions of ammonia with 4 and N-formyloxy-N-methylformamide 5. An N-alkyl group leads to a much larger activation energy in accordance with the experimental findings for N-acyloxy-N-alkylamides, which are resistant to attack by nucleophiles and are non-mutagenic.
Citation
ARKIVOC, 2(12), p. 143-160
ISSN
1551-7012
1551-7004
Link
Publisher
Arkat USA Inc
Title
SN2 reactions at amide nitrogen - theoretical models for reactions of mutagenic N-acyloxy-N-alkoxyamides with bionucleophiles
Type of document
Journal Article
Entity Type
Publication

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