Green and Solid-Phase Synthesis of New Dihydro-[1,2,4]Triazolo[1,5-a]Pyrimidine Scaffolds by Using Poly-Melamine-Formaldehyde as a Nitrogen-Rich Porous Organocatalyst

Abstract

This work presents a new catalytic application of porous poly-melamine-formaldehyde (mPMF) for the efficient synthesis of new dihydro-[1,2,4]triazolo[1,5-a]pyrimidines. According to the principals of green chemistry, the reaction was performed by the planetary ball milling process at ambient and neat conditions. The heterogeneous catalyst could be reused up to five runs with no reducing of catalytic efficiency. A variety of substituted dihydro-[1,2,4]triazolo[1,5-a]pyrimidines were obtained in good to excellent yields under eco-friendly conditions. This work revealed that bifunctional porous organic polymers (POPs) containing base sites and acceptor-donner hydrogen bonding groups, as well as high porosity could play a vital role in the promotion of the one-pot multicomponent reactions in the solid phase. The main merits of the current methodology include short reaction time, wide substrate-scope, and use of a metal-free heterogeneous organocatalyst, simple work-up process.