Azaquinoxalines was written by Bodforss, Sven. And the article was included in Justus Liebigs Annalen der Chemie in 1964.Application of 322-46-3 This article mentions the following:
A series of azaquinoxalines was prepared from 2,3-diaminopyridine (I) with α-dicarbonyl compounds Equivalent amounts of PhCH:CHCOCO2H (II) and I in EtOH yielded the I-II salt, decompose 144° (EtOH or hot H2O). I-II salt refluxed about 10 min. in AcOH gave about 20% 2-styryl-5(or 8)-aza-3-quinoxalone (III), 251° (AcOH). The ο-NO2 derivative (2 g.) of II and 1 g. I refluxed 4 hrs. in AcOH and EtOH yielded the 2-(ο-O2NC6H4CH:CH) analog of III, decompose 275° (HCONMe2). BzCH2COCO2H and I (equimolar amounts) mixed in EtOH, and the resulting salt refluxed in AcOH gave quant. the 2-BzCH2 analog (IV) of III, ∼283° (AcOH). IV (2 g.) in 20 g. concentrated H2SO4 and 2.5 g. P2O5 heated 2 days at 100° yielded 2-phenyl-5-azafuro[2,3b]quinoxaline (V), m. 251° (AcOH), and some SO3H derivative (VI) of V which was isolated as the pyridinium salt; the salt in H2O treated with dilute HCl gave VI. III (2.3 g.) in CHCl3 treated slowly in sunlight with 1.6 g. Br in AcOH, and the resulting crude dibromide refluxed with 10 cc. dry C5H5N gave VII (X = Br), which was dissolved in H2O and treated with NaClO4 to give VII (X = ClO4), brown-yellow microcrystals. I (2.3 g.) and 15 cc. (CO2Et)2 refluxed 1 hr. gave quant. 2,3-dihydroxy-5-azaquinoxaline, decompose above 300°. I (2 g.) and 4 g. Bz2 refluxed 12 hrs. with a few drops concentrated H2SO4 yielded 2,3-diphenyl-5-azaquinoxaline (VIII), m. 144°. (p-HOC6H4CO)2 (2 g.) and 1 g. I refluxed 2 days with 20 cc. EtOH and 2 cc. AcOH gave the bis(p-HOC6H4) analog of VIII, decompose 315°. I (2 g.) and 5 g. alloxan in EtOH-AcOH yielded alloxan-3(or 2)-[2(or 3)-aminopyridyl)imide, decompose ∼250° (reprecipitated from NH4OH with AcOH). Alloxan anil refluxed 2 days with 4N KOH, adjusted to about pH 10, and acidified with dilute HCl yielded 2-carboxy-3-hydroxy-5(or 8)-azaquinoxaline, decompose ∼280°, which dissolved in hot H2O and reprecipitated with HCl gave an unidentified, brown-red solid, decomposing above 345°. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Application of 322-46-3).
Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine is an N-heterocyclic moiety, and it can be easily prepared from ethylenediamine and 1,2-diketone, α-hydroxyketone, α-methyl ketone. A number of pyrazine-based derivatives were used as dyes or fluorescent probes.Application of 322-46-3