Chem. Pharm. Bull., 53(7),820-825, July 2005

Notes

Ab Initio Molecular Orbital Study of the Reactivity of Active Alkyl Groups. VI. Modified Reaction Model for the Elimination Process of Nitrosation Reaction

Hirohito IKEDA, Miho YUKAWA, and Tokihiro NIIYA^*

Faculty of Pharmaceutical Sciences, Fukuoka University; Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan. * To whom correspondence should be addressed. e-mail: niiya@fukuoka-u.ac.jp

The mechanisms of nitrosation of acetone through sodium enolate [CH₃COCH₂]−Na+ (1) or naked enolate [CH₃COCH₂]− (2) with tert-butyl nitrite (CH₃)₃CONO (3) were studied using ab initio molecular orbital (MO) methods. When the modified complex model was used in the elimination process, our results demonstrated the predominant formation of E-1-hydroxy-imino-2-oxo-propane CH₃COCH=NOH (4E), in which a counter-cation of the base catalyst did not participate during the reaction. On the other hand, participation of the counter-cation during the reaction contributed to the formation of the Z-isomer of 4 (4Z).

Key words nitrosation; active alkyl group; reaction mechanism; ab initio molecular orbital (MO) method; stereochemistry; oxime