Studies on Pyrimidine Derivatives. XXII. Site-selective Oxidation of Dimethylpyrimidines with Selenium Dioxide to Pyrimidine-minoaldehydes

抄録

The oxidation of 2, 4-dimethylquinoline and its 1-oxide with an equimolecular amount of selenium dioxide in boiling dioxane afforded 4-methylquinoline-2-carbaldehyde and its 1-oxide, respectively. This oxidation was applicable to the selective preparation of pyrimidine-4-carbaldehydes from dimethylpyrimidines. In case of pyrimidine derivatives, the presence of an N-oxide group facilitated the oxidation, but the isolated yields of the pyrimidinecarbaldehyde N-oxides were unsatisfactory, because of their instability.