Dedicated to Professor Hiriyakkanavar Ila in great admiration of her creative contributions to heterocyclic chemistry
Abstract
With the motivation to expand the compound library of specifically substituted pyrimidine derivatives, we prepared several pyrimidine-4-carbaldehydes. In most cases, the chemoselective oxidation of 4-hydroxymethyl-substituted pyrimidine derivatives could be achieved in good yields to provide the desired compounds. Alternatively, the aldehydes were prepared by Riley oxidation with selenium dioxide from the corresponding 4-methylpyrimidines. The formyl group of these compounds was employed as handle to generate alkynyl, cyano, oxazol-5-yl or β-ketoester substituents. Furthermore, two methods were found to prepare furo[3,2-d]pyrimidines. A serendipitously discovered reaction to a 6-(pyrimidin-4-yl)furo[3,2-d]pyrimidin-7-ol derivative involves a mechanistically interestingly ‘dimerization’ process with a benzoin addition as key step. Other compounds in this series contain amino, azido, or 1,2,3-triazol-1-yl groups. All these transformations to highly substituted pyrimidine derivatives demonstrate the synthetic versatility of pyrimidine-4-carbaldehydes and similar compounds.
Key words
azides - furo[3,2-d]pyrimidines - nitriles - oxazoles - oxidation - pyrimidine-4-carbaldehyde - triazoles
