Ureido

Ureido is a term used in organic chemistry to denote the ureido functional group, a structural motif derived from urea. The ureido moiety typically consists of a carbonyl group flanked by two nitrogen atoms, commonly described as -NH-CO-NH-. In many compounds this unit acts as a linker between two substituents and can function as both a hydrogen bond donor and acceptor.

In terminology, a fragment containing the ureido group is often described as ureido or as a carbamoyl linkage between two fragments. The ureido linkage is found in a variety of urea derivatives and related scaffolds, where it helps define conformation and intermolecular interactions.

Synthesis and installation of a ureido group generally involve forming a urea-type linkage. A common route is the condensation of an amine with an isocyanate to give R-NH-CO-NH-R'. Alternatively, carbamoylation of an amine with carbamoyl chlorides or other carbamoylating reagents can install a ureido fragment.

Applications and occurrence: ureido motifs are widely used in medicinal chemistry as urea-based linkers and in the design of small-molecule drugs. They also appear in polymer chemistry as the repeating units of polyurea materials. The ureido group influences hydrogen bonding, polarity, and conformational preferences of molecules.

See also: Urea, Isocyanate, Carbamoyl, Polyurea.