Trifluoromethylated 2-amino-pyrimidine N-oxides have been synthesized by reaction of the 3-amino-5-methyl-1,2,4-oxadiazolewith trifluoromethyl-b-diketones in the presence of perchloric acid, followed by hydrolysis. In this ring-to-ring transformation an initialformation of (unisolated) 1,2,4-oxadiazole-pyrimidinium salts, and subsequent ring-opening at the oxadiazole moiety occurs. Isolation of2-(hydroxyamino)-pyrimidine from the reaction mixture evidenced the presence of a competing pathway where the N(4) nitrogen of theoxadiazole is involved in the formation of a regioisomeric pyrimidinium salt. The effect of the trifluoromethyl group on the productdistribution is discussed. By X-ray analysis, the crystal structure of two different N-oxide regioisomers has been unambiguously ascertained.
|Numero di pagine||7|
|Stato di pubblicazione||Published - 2006|
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Drug Discovery