Electronic transitions in the aromatic chlorazines. III. Absorption spectra of monochloro quinoxalines, phthalazines, quinazolines, and cinnolines was written by Favini, Giorgio;Simonetta, Massimo. And the article was included in Gazzetta Chimica Italiana in 1960.Synthetic Route of C8H5ClN2 This article mentions the following:
The absorption spectra of 2-, 5-, and 6-chloroquinoxalines (I, II, III), 2-, 4-, and 6-chloroquinazolines (IV, V, VI), 1-, 5-, and 6-chlorophthalazines (VII, VIII, IX), and 3-, and 4-cinnolines (X, XI) were measured in isoöctane and in MeOH between 220 and 450 mμ. Condensation of o-(H2N)2C6H4 and OC(CO2Et)2 and hydrolysis, decarboxylation of the 2-hydroxyquinoxaline-3-carboxylic acid and chlorination with POCl3 gave I, m. 46-7° (C5H12). Acetylation of o-ClC6H4NH2 and nitration with fuming HNO3, deacetylation of the crystalline 2,6-Cl-(O2N)C6H3NHAc with NaOH, reduction with SnCl2, and condensation of the reduction product with OHCCHO.(NaHSO3)2 yielded II, m. 61-2° (petr. ether). Similarly, com. 4,2-Cl(H2N)C6H3NH2 was transformed to III, m. 63-4° (petr. ether). Reduction of o-O2NC6H4CHO, condensation with urea, and chlorination of the 2-quinazolone with PCl3 and POCl3 gave IV, m. 108° (ligroine). HCONH2 condensed with o-H2NC6H4CO2H and the 4-quinazolone chlorinated with PCl5 and POCl3 successively yielded V, m. 99-100° (petr. ether). Nitration of 3-ClC6H4CHO and condensation with HCONH2 followed by reduction with Zn in AcOH gave VI, m. 145° (dilute alc.). Phthalide transformed through the Br derivative into o-OHCC6H4CO2H, condensed with N2H4.H2O to the phthalazone and chlorinated with POCl3 yielded VII, m. 110-11° (ligroine). Conversion of 3,4-Me2C6H3NH2 by the Sandmeyer reaction gave 10 g. 3,4-Me2C6H3Cl, converted through 3,4-(CHBr2)2C6H3Cl to 3,4-(OHC)2C6H3Cl and condensed with N2H4 to yield 0.4 g. IX, m. 132°. α-Tetrahydronaphthylamine (5 g.) converted according to Sandmeyer to α-chlorotetrahydronaphthalene and submitted to oxidative degradation, the isomeric mixture condensed with N2H4, the product chlorinated with POCl3 and the mixture of dichlorophthalazines (0.2 g.) treated with HI and P to eliminate the Cl of the heterocyclic ring gave a small amount of VIII. HCN added to o-O2NC6H4CHO and the nitrile saponified, the NO2 group reduced catalytically and the acid diazotized, reduced with SnCl2 and the 3-hydroxycinnoline chlorinated with POCl3 gave X, m. 90-1° (ligroine). MeCOPh nitrated and reduced with Sn and HCl, the o-H2NC6H4COMe diazotized and transformed into 4-hydroxycinnoline, treated successively with PCl5 and POCl3, and recrystallized from ligroine gave XI, m. 78-9°. The nature of the bands observed and the infuence exerted on the absorption maximum by introduction of an atom of Cl into the benzodiazine structure were discussed. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Synthetic Route of C8H5ClN2).
6-Chloroquinoxaline (cas: 5448-43-1) belongs to quinoxaline derivatives. Condensed heterocycles of quinoxalines have become attractive targets in synthetic and medicinal chemistry due to their significant biological activities. 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.Synthetic Route of C8H5ClN2
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider