9H-Pyrimido[4,5-b]indole-2,4-diones. The acid-catalyzed cyclization of 6-(phenylhydrazino)uracils was written by Wright, G. E.. And the article was included in Journal of Heterocyclic Chemistry in 1976.Formula: C6H9N3OS This article mentions the following:
The 6-(phenylhydrazino)uracils under facile Fischer-type cyclization in both N HCl and in HCO2H at reflux to give 9H-pyrimido[4,5-b]indol-2,4-diones, e.g., I. Yields are related to substituent effects and side reactions. In the reaction of 6-(phenylhydrazino)uracil itself with HCl, the major competing reaction is hydrolysis to barbituric acid and PhNHNH2, whereas in HCO2H 1-phenyl-3-carboxamidomethyl-1,2,4-triazole is obtained. NMR spectra of pyrimido[4,5-b]indole-2,4-diones provide examples of peri effects on H chem. shifts. In the experiment, the researchers used many compounds, for example, 6-Amino-3-methyl-2-(methylthio)pyrimidin-4(3H)-one (cas: 54030-56-7Formula: C6H9N3OS).
6-Amino-3-methyl-2-(methylthio)pyrimidin-4(3H)-one (cas: 54030-56-7) belongs to pyrimidine derivatives. The pyrimidine nitrogenous bases are derived from the organic compound pyrimidine through the addition of various functional groups. A Cu-catalyzed and 4-HO-TEMPO-mediated [3 + 3] annulation of commercially available amidines with saturated ketones enables an efficient and facile synthesis of structurally important pyrimidines via a cascade reaction of oxidative dehydrogenation/annulation/oxidative aromatization.Formula: C6H9N3OS
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia