Pyridine derivatives are chemical compounds that contain a pyridine ring, which is a six-membered aromatic ring with one nitrogen atom. These derivatives are important in various fields, including pharmaceuticals, agrochemicals, and materials science, due to their diverse biological activities and chemical properties. Common examples of pyridine derivatives include nicotine, pyridoxine (vitamin B6), and isoniazid, a medication used to treat tuberculosis. The presence of different functional groups attached to the pyridine ring can significantly alter the compound's reactivity and biological function, making them valuable in drug design and synthesis.