Solid-state synthesis of polyfunctionalized 2-pyridones and conjugated dienes

Functionalized 2-pyridones are important biologically active compounds, DNA base analogues and synthetic intermediates. Herein, we report a simple, green, solid-state synthesis of differently substituted 2-pyridones. It starts from commercially available amines and activated alkynes, uses silica gel (15%Cs₂CO₃/SiO₂) as the solid phase and a reaction vial as the only equipment. If necessary, heating is performed in a laboratory oven. Since most reactions are completed within a few hours, no additional energy consumption is required. The syntheses do not require solvents and other reagents and are easily monitored by standard analytical techniques. The atom economy is high, since all atoms of reactants are present in the products and EtOH is the only by-product. The syntheses produce polyfunctionalized conjugated dienes as the only intermediates, which are also important building blocks.