An Unprecedented Approach to 4,5-Disubstituted Pyrimidine Derivatives by a ZnCl₂-Catalyzed Three-Component Coupling Reaction

We have developed a ZnCl₂-catalyzed three-component coupling reaction involving a variety of functionalized enamines, triethyl orthoformate, and ammonium acetate, which leads to the production of 4,5-disubstituted pyrimidine derivatives in a single step. The procedure can be successfully applied to the efficient synthesis of mono- and disubstituted pyrimidine derivatives, using methyl ketone derivatives instead of enamines.