Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Pyrimidines are synthesized via a direct oxidative one-pot, three-component, reaction between 1,3-diketone, benzaldehydes, and ammonium acetate in the presence of catalytic amounts of Keggin-type heteropolyacids under refluxing conditions in good yields.