pyridin2yl

Pyridin-2-yl, commonly written as 2-pyridyl, is a substituent derived from the heteroaromatic compound pyridine by removing the hydrogen at the second carbon of the ring. In systematic IUPAC terms, the substituent is named pyridin-2-yl, while 2-pyridyl remains a widely used common variant.

The 2-pyridyl group attaches to another molecule through the C2 position of the pyridine ring, leaving the ring nitrogen at position 1 intact. This arrangement gives the substituent an aromatic and relatively electron-poor character. The pyridine nitrogen can serve as a coordination site in metal complexes, and 2-pyridyl fragments frequently appear in ligands that chelate metals, such as in 2,2'-bipyridine and related derivatives.

Applications of the 2-pyridyl substituent are broad in organic synthesis, medicinal chemistry, and materials science. It is a common building block for constructing heteroaromatic compounds and can influence the electronic and binding properties of a molecule. In synthetic chemistry, 2-pyridyl groups are often introduced via cross-coupling reactions, including Suzuki-Miyaura couplings, using 2-pyridyl reagents derived from 2-halo or 2-pyridyl boron/organometallic partners.

Synthesis methods typically include palladium- or nickel-catalyzed cross-couplings of 2-halo pyridines with appropriate nucleophiles, preparation from 2-pyridyl boron or zinc reagents, or directed lithiation of pyridine followed by electrophilic trapping. Alternative approaches involve C–H activation strategies to install other substituents adjacent to the ring nitrogen.

See also: pyridinyl, pyridin-4-yl, and related heteroaryl substituents.