HETEROCYCLES

Heterocycles has a pay-per-view service for Non-subscribers.
You will be able to directly purchase the full text article through PayPal.
Your purchased Paper can be downloaded after the payment is completed.
An e-mail will be sent the URL to download the paper.
If you have any questions, please contact: purchase@heterocycles.com

Price: ¥ 4,400 (Yen only)
Period: This Article can be accessed for 7 days.

■ On the Structural Ditermination of Pyrimidine N-Oxides

Takao Sakamoto, Setsuko Niitusma, Michinao Mizugaki, and Hiroshi Yamanaka*

*Pharmaceutical Institute, Tohoku University, Aobayama, Sendai 980-8578, Japan

Abstract

Direct N-oxidation of 2-alkyl-4-ethyl-6-methylpyrimidines with hydrogen peroxide in glacial acetic acid afforded their 1-oxides and 3-oxides. Acid hydrolysis of the 1-oxides and the 3-oxides caused the ring transformation leading to 3-methyl-5-ethyl- (VII) and 3-ethyl-5-methyl-isoxazole (VIII), respectively. This result obviously demonstrated the structure of the N-oxides.
Observing displacements of signals on the NMR spectra of the N-oxides induced by adding a shift reagent, tris(heptafluorobutanoylpivaloylmethanato)europium_III), it is concluded that the NMR spectroscopy with the lanthanide is generally applicable to structural elucidation of pyrimidine N-oxides.