Substituent effect on local aromaticity in mono and di-substituted heterocyclic analogs of naphthalene was written by Mohajeri, Afshan;Shahamirian, Mozhgan. And the article was included in Journal of Physical Organic Chemistry in 2010.Electric Literature of C9H8N2O This article mentions the following:
A quant. study on local aromaticity has been performed on a series of mono- and di-substituted biheterocycles (quinoline, isoquinoline, quinoxaline, quinazoline). Three electronically based indexes (PDI, ATI, and FLU) have been employed to investigate the substituent effect on the π-electron delocalization in both heterocycle and benzenoid rings. Three typical substituents (Cl, OCH3, and CN) with different inductive and resonance power have been selected. Generally, substituent causes a reduction in aromaticity irresp. of whether it is electron attracting or electron donating. It is shown that the maximum aromaticity exhibits a similar trend of Cl > CN > OCH3 for all the studied rings. Moreover, it is found that the substituent situation with respect to the heteroatom has a significant influence on the aromaticity. It results from our study that in di-substituted derivatives, irresp. of whether the two substituents form a meta or para isomer, they preferably choose the position which leads to the maximum aromaticity character. Copyright © 2009 John Wiley & Sons, Ltd. In the experiment, the researchers used many compounds, for example, 6-Methoxyquinoxaline (cas: 6639-82-3Electric Literature of C9H8N2O).
6-Methoxyquinoxaline (cas: 6639-82-3) belongs to quinoxaline derivatives. Quinoxaline is isomeric with other naphthyridines including quinazoline, phthalazine and cinnoline. Modifying quinoxaline structure it is possible to obtain a wide variety of biomedical applications, namely antimicrobial activities and chronic and metabolic diseases treatment.Electric Literature of C9H8N2O
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider