Novel and Facile Catalytic Synthesis of 2,4-Dioxopyrido[2,3-d]pyrimidine Derivatives in Water.

Reactions of 6-amino-1,3-dimethyluracil with substituted α-ketoalkynes using homogeneous nickel catalyst in aqueous alkaline medium, afford substituted 2,4-dioxopyrido[2,3-d]pyrimidine derivatives in quantitative yields under very mild conditions. A mechanism has been proposed for the reaction involving the nucleophilic attack of Ni(0) anion, formed in situ onto the triple bond of the substrate. All the synthesized pyrimidines were well characterized.