imidazolidinonebased

Imidazolidinone-based compounds are those in which the imidazolidinone ring is the defining structural element. The imidazolidinone ring is a five-membered heterocycle containing two nitrogens and a carbonyl at position 2, commonly described as 4,5-dihydro-1H-imidazol-2-one. In these molecules, the ring may be standalone or part of a larger framework, with various substituents at N1 and N3 or fused to other rings. The term covers a broad class, including small molecules, fragments, and catalytic scaffolds.

In organic synthesis, imidazolidinone-based compounds are best known as chiral organocatalysts. The imidazolidinone scaffold can form a reactive iminium ion with enals or enones, enabling enantioselective transformations. The best-known example is the MacMillan-type imidazolidinone organocatalyst, widely used for enantioselective aldol, Diels–Alder, Michael, and related reactions. These catalysts rely on the ability of the imidazolidinone to act as a hydrogen-bond donor and to generate an activated electrophile in a chiral environment.

Beyond catalysis, imidazolidinone motifs appear in medicinal chemistry and material science. They serve as building blocks in drug design, where the ring can influence conformation and hydrogen-bonding patterns, or as protecting groups and scaffolds in synthetic routes. Imidazolidinone derivatives also appear in polymeric formats, where the ring contributes to rigidity or hydrogen-bonding networks.

Synthesis typically proceeds from amino alcohols or imines, followed by cyclization to form the imidazolidinone core and subsequent N-substitution or functionalization. Substituent patterns vary widely, leading to a range of physical and chemical properties.