In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Structures of pyridine and quinoline-N-oxide, published in 1970, which mentions a compound: 1127-45-3, Name is 8-Hydroxyquinoline 1-oxide, Molecular C9H7NO2, Synthetic Route of C9H7NO2.
8-Hydroxyquinoline 1-oxide (I) and 2-(hydroxymethyl)pyridine 1-oxide (II) exhibited lengthened N-O bond distances (1.333 and 1.332 Å) due to delocalization of the nonbonding electron on the O as a result of H bonding. The H bond between the hydroxyl H and the dative O is intramol. (1.42 Å long) in I and intermol. in II (1.99 Å long). The pyridine and quinoline moieties are planar. Crystals have monoclinic symmetry, space group P21/c, and Z = 4. Compound, lattice constants a, b, c, and cos. β are: I, 12.136, 4.921, 13.138 Å, -0.3376; II, 7.079, 8.046, 10.599 Å, -0.2254.
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Reference:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider