Tzeng, Cherng Chyi; Rychlewska, Urszula; Hodgson, Derek J.; Panzica, Raymond P. published the artcile< 4-Azapteridines. 2. Spectral, chromatographic, and x-ray crystallographic studies concerning the mode of covalent addition to the pyrazino[2,3-e]-as-triazine ring system>, HPLC of Formula: 4956-05-2, the main research area is pyrazinotriazine dihydroxy crystal structure; aminotriazine cyclocondensation glyoxal.
The first examples of the unknown pyrazino[2,3-e]-as-triazine ring system, i.e., the 6,7-dihydroxy-5,6,7,8-tetrahydropyrazino[2,3,-e]-as-triazines, have been prepared by ring closure of selected 5,6-diamino-as-triazines with 40% aq glyoxal. These 4-azapteridines experience a novel exchange process with alcs. at the C(7)-position. When dissolved in alc. and stirred at room temperature, the 7-alkoxy, 6-hydroxy analogs are formed and isolated. If alcs. are used as the solvent during ring closure, only the latter compounds are obtained. Initially, cyclization of the ortho-diamino-as-triazines with glyoxal proceeds in a stereoselective manner giving rise to both the cis and trans adducts. A single-crystal x-ray diffraction study of the pyrazinotriazine I has determined the predominant and most stable adduct to be the trans (R,R or S,S)-isomer. NMR spectroscopy has verified the intermediacy of the cis adduct, but because of the aforementioned exchange process only the trans isomer is isolated. The site of exchange on these σ-adducts has been rigorously established as C(7). A plausible reaction mechanism by which this exchange process occurs is presented.
Journal of Heterocyclic Chemistry published new progress about Crystal structure. 4956-05-2 belongs to class pyrimidines, and the molecular formula is C3H2BrN3O2, HPLC of Formula: 4956-05-2.
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia