The thermolysis of polyazapentadienes. Part 2. Formation of quinoxalines from 5-aryl-1-phenyl-1,2,5-triazapentadienes was written by McNab, Hamish. And the article was included in Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1972-1999) in 1982.Formula: C9H8N2O This article mentions the following:
Gas phase pyrolysis of RC6H4N:CHCH:NNHPh (I; R = p-Me, -OMe, -Cl, -Ac) at 600° and 10-2 Torr gave the quinoxalines II (R = Me, OMe, Cl, Ac, R1 = H) in 13-42% yield. Similarly, I (R = o-Me, -OMe, -Cl) gave II (R = H, R1 = Me, OMe, Cl) but in lower yields; II (R = R1 = H) was the major by-product due to ipso attack and elimination of the substituent. Meta-substituted I gave mixtures of 5- and 6-substituted quinoxalines on pyrolysis. The 5-isomer is dominant for compounds with meta-alkyl substituents whereas the 6-isomer is the major product for those with electron-withdrawing or -donating meta-substituents. In the experiment, the researchers used many compounds, for example, 6-Methoxyquinoxaline (cas: 6639-82-3Formula: C9H8N2O).
6-Methoxyquinoxaline (cas: 6639-82-3) belongs to quinoxaline derivatives. Quinoxalines are important class of heterocyclic compounds, associated with wider pharmacological applications. The parent substance of the group, quinoxaline, results when glyoxal is condensed with 1,2-diaminobenzene. Substituted derivatives arise when α-ketonic acids, α-chlorketones, α-aldehyde alcohols and α-ketone alcohols are used in place of diketones.Formula: C9H8N2O
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider