Nitrogen heterocycles are organic compounds that contain a ring structure with at least one nitrogen atom in the ring. These compounds are significant in various fields, including pharmaceuticals and agrochemicals, due to their diverse chemical properties and biological activities. Common examples include pyridine, imidazole, and quinoline. The presence of nitrogen in the ring can influence the compound's reactivity and stability, making nitrogen heterocycles valuable in synthetic chemistry. They often serve as building blocks for more complex molecules and are found in many natural products, including alkaloids and nucleotides.