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 Naphthyridine chemistry. V. One-step synthesis of 1,8-naphthyridines, published in 1967, which mentions a compound: 1569-17-1, Name is 4-Methyl-1,8-naphthyridine, Molecular C9H8N2, Electric Literature of C9H8N2.
cf. CA 66, 6881q; 65, 16955a; 64, 5057c. 2-Aminopyridine treated with Utermohlen’s “”sulfo-mix”” (CA 38, 9735) and glycerol gave 30% 1,8-naphthyridine. Similarly were prepared 2-methyl-, 4-methyl-, and 2,4-dimethyl-1,8-naphthyridines (I,II, and III). N.M.R. spectra data are given for the compounds
Here is just a brief introduction to this compound(1569-17-1)Electric Literature of C9H8N2, more information about the compound(4-Methyl-1,8-naphthyridine) is in the article, you can click the link below.
Reference:
1,8-Naphthyridine – Wikipedia,
1,8-Naphthyridine | C8H6N2 – PubChem