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 Effect of substrate analogs on the circular dichroic spectra of thymidylate synthetase from Lactobacillus casei, published in 1975, which mentions a compound: 20198-19-0, Name is 2-Aminoquinazolin-4(3H)-one, Molecular C8H7N3O, Formula: C8H7N3O.
CD studies at 290-400 nm with thymidylate synthetase from L. casei revealed characteristic Cotton effects in the presence of various folate analogs plus 5-fluoro-2′-deoxyuridylate (I). Omission of either substrate analog prevented the appearance of the Cotton effects. When I and racemic 5,10-methylenetetrahydrofolate (II) were mixed with the enzyme, a ternary complex resulted which gave distinctive minor neg. ellipticity bands at 285 and 332 nm and a major pos. band at 305 nm. Similar results were obtained with the ternary complex containing (+)-II but the enzymically inactive (-)-II induced only the pos. band at 305 nm. More intense Cotton effects were elicited by (±)-5,11-methylenetetrahydrohomofolate with a major pos. ellipticity band at 308 nm and a minor neg. band at 335 nm. A ternary complex was also formed with dihydrofolate, which provided a major CD band at 305 nm and a broad minor neg. band in the region of 335 nm. Deoxyuridylate and thymidylate also formed ternary complexes with dihydrofolate, but their ellipticity bands were much less intense. Other folate analogs that formed ternary complexes with I to provide characteristic CD spectra were tetrahydrofolate, tetrahydrohomofolate, 10-methyltetrahydrofolate, and 2-amino-4-hydroxyquinazoline. By measuring the increment in ellipticity at 305 nm on addition of specific ligands to enzyme solutions, it was determined that the L. casei thymidylate synthetase contains 2 binding sites for I and for each of the diastereoisomers of II. An improved procedure is presented for the large-scale purification and crystallization of L. casei thymidylate synthetase.
In addition to the literature in the link below, there is a lot of literature about this compound(2-Aminoquinazolin-4(3H)-one)Formula: C8H7N3O, illustrating the importance and wide applicability of this compound(20198-19-0).
Reference:
Chiral nitrogen ligands in late transition metal-catalysed asymmetric synthesis—I. Addressing the problem of ligand lability in rhodium-catalysed hydrosilations,
Nitrogen-Containing Ligands for Asymmetric Homogeneous and Heterogeneous Catalysis