Heterocyclic Building Blocks-quinoxaline

Action of o-phenylenediamines upon dihydroxytartaric acid was written by Chattaway, Frederick D.;Humphrey, William G.. And the article was included in J Chem. Soc. in 1929.Formula: C8H5ClN2 This article mentions the following:

When Na dihydroxytartrate is heated with aqueous o-C₆H₄(NH₂)₂, 2 mols of the diamine react with 1 mol. only of the salt, forming quinoxaline-2,3-dicarboxy-o-phenylenediamide (I); Na dihydroxytartrate is only very sparingly soluble in H₂O and any excess above 1 mol. remains in suspension unchanged. When the filtered alk, solution is partly neutralized with HCl, I seps. as a colorless crystalline powder, stable in neutral solution and dissolving readily in cold dilute aqueous alkali, from which it is reprecipitated on addition of a deficiency of acid. It dissolves in hot dilute HCl (1:50), but on cooling, the o-phenylenediamine salt, (II) of quinxaline-2,3-dicarboxylic acid (III) seps; whereas, if it is dissolved in hot moderatelv concentrated HCl (1:1), III separated on cooling o-phenylenediamine-HCl remaining in solution The II and III may consequently be obtained directly from the original yellow condensation solution, the former by making the solution weakly acid with HCl, and the latter by saturating it with gaseous HCl. Attempts to acetylatc or benzoylate I by the usual methods also cause decomposes, with formation of the di-Ac or the di-Bz derivative of o-C₆H₄(NH₂)₂. Heated with Ac₂O, III yields the anhydide, while dry NH₃ on this anhydride in C₆H₄ suspensions gives the NH₄ salt of 3-carbamylquinoxaline-2-carboxylic acid (IV), from which the acid itself may be obtained on acidification. This amic acid is converted into the corresponding imide (V) on being heated above its m. P., and into the Ac derivative of the imide on boiling with Ac₂O. On being heated above its m. p., III decomposes, evolving CO₂ and yielding a small quantity (10%) of quinoxaline; better yields (30%) of this base are obtained by heating the NH₄ salt of the acid. In common with other N bases, quinoxaline forms a stable, well-crystallized monotetrachloroiodiede. Similarly, Na chloroquinoxaline-2,3-dicarboxy-p-chloro-o-phenylenediamide, from which the p-chloro-o-phenylenediamine salt of 6-chloroquinoxaline-2,3-dicarboxylic acid, and the free acid (VI) are obtained by heating with dilute and with concentrated HCl, resp. p-Bromo-o-phenylenediamine gives the corresponding Br derivative These halogen-substituted derivatives are considerably less soluble than the unsubstituted compounds, and are therefore more readily prepared and purified; otherwise their reactions are analogous. The following compounds were prepared and characterized: I, m. 184° (decomposition). II, lemon-yellow, m. 186° (decomposition). III, prisms containing 2 mols. H₂O of crystallization, m. 190° (decomposition after loss of H₂O at 110°); Et ester, C₁₄H₁₄O₄N₂, prisms, m. 83°; NH₄ salt, m. 220-30°; anhydride, pale yellow prisms decomposing and charring 250-60°. IV, m. 190-5° (decomposition). V, pale yellow, m. about 260° (decompose); Ac derivative, leaflets, m. about 220° (decomposition). Quinoxaline mono-tetrachloroiodide, C₆H₄N₂. HICl₄, m. 125-30° (decomposition). 6-Chlroquinoxaline-2,3-dicarboxy-p-chloro-o-phenylenediamide, C₁₆H₈O₂N₄Cl₂, m. 207° (decomposition) (p-chloro-o-phenylenediamine salt, C₁₆H₁₈O₄N₄Cl₃, m. 205° (decomposition)); 6-bromoquinoxaline-2,3-dicarboxy-p-bromo-o-phenylenediamide, m. 198° (decomposition) (p-bromo-o-phenyleneamine salt, m. 199° (decomposition)). VI, m. 175° (decomposition) (anhydride,m. 235-40° (decomposition), Et H ester, m. 159°; di-Et ester, m. 60°; NH₄ salt, m. 215-25° (decomposition)). 6-Chloroquinoxaline, m. 60°, 6-Bromoquinoxaline-2,3-dicarboxylic acid, m. 172° (decomposition) (anhydride, m. 235-45° (decomposition), Et H ester, m. 161°, di-Et ester, m. 69°, NH₄ salt, m. 235-40° (decomposition)). 6-Bromoquinoxaline, m. 56°. Pyrazinetetracarboxylic acid (by oxidation of the anhydride of III), m. 205° (decomposition), di-K di-H salt is crystalline, tetra-Et ester, m. 104°. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Formula: C8H5ClN2).

6-Chloroquinoxaline (cas: 5448-43-1) belongs to quinoxaline derivatives. Quinoxalines are important class of heterocyclic compounds, associated with wider pharmacological applications. The antitumoral properties of quinoxaline compounds have been of interest. Recently, quinoxaline and its analogs have been investigated as the catalyst’s ligands.Formula: C8H5ClN2

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

QCM-4 a novel 5-HT₃ antagonist attenuates the behavioral and biochemical alterations on chronic unpredictable mild stress model of depression in Swiss albino mice was written by Kurhe, Yeshwant;Radhakrishnan, Mahesh;Gupta, Deepali;Devadoss, Thangaraj. And the article was included in Journal of Pharmacy and Pharmacology in 2014.Quality Control of Ethyl 3-chloroquinoxaline-2-carboxylate This article mentions the following:

Objectives: The inconsistent therapeutic outcome necessitates identifying novel compounds for the treatment of depression. Therefore, the present study is aimed at evaluating the antidepressant-like effects of a novel 5-HT₃ receptor antagonist 3-methoxy-N-p-tolylquinoxalin-2-carboxamide (QCM-4) on chronic unpredictable mild stress (CUMS) induced behavioral and biochem. alterations in mice. Methods: Animals were subjected to different stressors for a period of 28 days. Thereafter, battery tests like locomotor score, sucrose preference test, forced swim test (FST), tail suspension test (TST), elevated plus maze (EPM) and open field test (OFT) were performed. Biochem. assays like lipid peroxidation, nitrite levels, reduced glutathione (GSH), catalase and superoxide dismutase (SOD) were assessed in brain homogenate. Key findings: QCM-4 dose dependently reversed the CUMS induced behavioral and biochem. alterations by increasing the sucrose consumption, reducing the immobility time in FST and TST, increasing the percent time in open arm in EPM and increasing the ambulation along with the rearings and decreased number of fecal pellets in OFT. Further, biochem. alterations were attenuated by QCM-4 as indicated by reduced lipid peroxidation and nitrite levels and elevated antioxidant enzyme levels like GSH, catalase and SOD. Conclusions: QCM-4 attenuated the behavioral and biochem. derangements induced by CUMS in mice, indicating antidepressant behavior of the novel compound In the experiment, the researchers used many compounds, for example, Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0Quality Control of Ethyl 3-chloroquinoxaline-2-carboxylate).

Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0) belongs to quinoxaline derivatives. Condensed heterocycles of quinoxalines have become attractive targets in synthetic and medicinal chemistry due to their significant biological activities. They are well-known for application in organic light emitting devices, polymers and pharmaceutical agents. The quinoxaline-containing polymers are applicable in optical devices due to their thermal stability and low band gap.Quality Control of Ethyl 3-chloroquinoxaline-2-carboxylate

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Selective Functionalization of Benzo-Fused N-Heterocycles by Using In Situ Trapping Metalations was written by Nishimura, Rodolfo H. V.;Murie, Valter E.;Vessecchi, Ricardo;Clososki, Giuliano C.. And the article was included in ChemistrySelect in 2020.Computed Properties of C8H5ClN2 This article mentions the following:

Some benzo-fused N-heterocycles, e.g., I were prepared by regioselective metalation of quinoline, isoquinoline, quinoxaline and quinazoline with LiTMP in the presence of zinc chloride. Applying this strategy to synthesize an analog of the antitumor verubulin illustrated its relevance for medicinal chem. Computational calculations of the pKa values of the aromatic hydrogens helped to rationalize substrate reactivity and metalation regioselectivity by the complex-induced proximity effect concept. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Computed Properties of C8H5ClN2).

6-Chloroquinoxaline (cas: 5448-43-1) belongs to quinoxaline derivatives. Compounds possessing quinoxaline derivatives were bestowed with a variety of significant biological properties such as antiviral, antimalarial, anticancer, DNA intercalation, DNA duplex stabilization, and many others. Quinoxalines are used as dyes, pharmaceuticals, and antibiotics such as echinomycin, levomycin exhibiting antitumoral properties. Quinoxalines establish also the basis of anthelmintics and receptor antagonists.Computed Properties of C8H5ClN2

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Rhodium-catalyzed transfer hydrogenation of quinoxalines with water as a hydrogen source was written by Zhang, Xia;Chen, Jingchao;Khan, Ruhima;Shen, Guoli;He, Zhenxiu;Zhou, Yongyun;Fan, Baomin. And the article was included in Organic & Biomolecular Chemistry.SDS of cas: 5448-43-1 This article mentions the following:

Rhodium-catalyzed transfer hydrogenation of quinoxalines with water as a hydrogen source is reported. The reaction allows the simple preparation of 1,2,3,4-tetrahydroquinoxalines under mild conditions. The deuterium-labeling experiment confirmed that water is the sole hydrogen source in the transfer hydrogenation reaction. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1SDS of cas: 5448-43-1).

6-Chloroquinoxaline (cas: 5448-43-1) belongs to quinoxaline derivatives. Quinoxaline derivatives are important constituents of pharmacologically active compounds, including as well as for RNA synthesis inhibition, reactive dyes and pigments, azo dyes, flurox Cylin Dyes, Corrosion Inhibitors and Photovoltaic Polymers. They are well-known for application in organic light emitting devices, polymers and pharmaceutical agents. The quinoxaline-containing polymers are applicable in optical devices due to their thermal stability and low band gap.SDS of cas: 5448-43-1

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

1-Alkyl-4-oxo-1,4-dihydropyrido[2,3-b]quinoxaline-3-carboxylic acids with antibacterial action was written by Pesson, Marcel;De Lajudie, Pierre;Antoine, Michel;Chabassier, Simone;Girard, Philippe. And the article was included in Comptes Rendus des Seances de l’Academie des Sciences, Serie C: Sciences Chimiques in 1976.SDS of cas: 49679-45-0 This article mentions the following:

Pyridoquinoxalinecarboxylic acids I (R = H; R1 = Me, Et; R2 = H, Me, Cl, OMe; R3 = H, Me, OMe) were prepared by treating the quinoxalines II (R = Me, Et, R4 = Cl) with R1NHCH2CH2CO2H, esterifying II (R4 = NR1CH2CH2CO2H), cyclizing II (R4 = NR1CH2CH2CO2R), brominating-dehydrobrominating the dihydro derivatives of I (R = Me, Et), and saponifying I (R = Me, Et). I have bactericidal activity, which is reduced by substitution in the 7- or 8-positions. In the experiment, the researchers used many compounds, for example, Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0SDS of cas: 49679-45-0).

Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0) belongs to quinoxaline derivatives. Quinoxaline derivatives are important constituents of pharmacologically active compounds, including antibacterial, antibiotic and antineoplastic, antifungal, anti-inflammatory and analgesic drugs. They are well-known for application in organic light emitting devices, polymers and pharmaceutical agents. The quinoxaline-containing polymers are applicable in optical devices due to their thermal stability and low band gap.SDS of cas: 49679-45-0

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Nickel-Catalyzed C-N Cross-Coupling of Ammonia, (Hetero)anilines, and Indoles with Activated (Hetero)aryl Chlorides Enabled by Ligand Design was written by McGuire, Ryan T.;Paffile, Julia F. J.;Zhou, Yuqiao;Stradiotto, Mark. And the article was included in ACS Catalysis in 2019.Formula: C8H5ClN2 This article mentions the following:

The Ni(II) precatalyst (C1) featuring the phosphonite ancillary ligand Phen-DalPhos (L1) was employed in the cross-coupling of (hetero)anilines with (hetero)aryl chlorides and in the diarylation of ammonia with (hetero)aryl chlorides to afford heteroatom-dense di(hetero)arylamines. The PAd2-DalPhos precatalyst C4 provided complementary reactivity in cross-couplings of indoles with (hetero)aryl chlorides. Taken together, the demonstration of room-temperature reactivity within each of the reaction classes examined and the observation of useful chemoselectivity at low loading (≤0.5 mol % Ni) and on gram-scale distinguishes C1 and C4 from other metal catalysts (i.e., copper, palladium, nickel, or other) within the field of C-N cross-coupling chem. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Formula: 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. Quinoxaline-1,4-di-N-oxide derivatives have shown to improve the biological results and are endowed with anti-viral, anti-cancer, anti-bacterial, and anti-protozoal activities with application in many other therapeutic areas.Formula: C8H5ClN2

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Thiazolo[5,4-f]quinoxalines, Oxazolo[5,4-f]quinoxalines and Pyrazino[b,e]isatins: Synthesis from 6-Aminoquinoxalines and Properties was written by Lassagne, Frederic;Sims, Joshua M.;Erb, William;Mongin, Olivier;Richy, Nicolas;El Osmani, Nour;Fajloun, Ziad;Picot, Laurent;Thiery, Valerie;Robert, Thomas;Bach, Stephane;Dorcet, Vincent;Roisnel, Thierry;Mongin, Florence. And the article was included in European Journal of Organic Chemistry in 2021.Name: 3-Chloroquinoxalin-6-amine This article mentions the following:

The regioselective iodination of different 2-mono-, 3-mono- and 2,3-disubstituted 6-aminoquinoxalines, which took place at their 5-position, was rationalized on the basis of Hueckel theory calculations Oxazolo- and thiazolo[5,4-f]quinoxaline analogs of reported disease-related protein kinases inhibitors were synthesized from the obtained 6-amino-5-iodoquinoxalines by using as key step copper-catalyzed azole ring formation. Pyrazino[b,e]isatins were obtained, for the first time, from the same substrates by recourse to Sonogashira coupling, alkyne hydration, and oxidative cyclization. The absorption and emission properties of the most promising compounds were recorded. In addition, most of the synthesized polycycles were evaluated as protein kinase inhibitors and for their antiproliferative activity towards cancer cells. In the experiment, the researchers used many compounds, for example, 3-Chloroquinoxalin-6-amine (cas: 166402-16-0Name: 3-Chloroquinoxalin-6-amine).

3-Chloroquinoxalin-6-amine (cas: 166402-16-0) belongs to quinoxaline derivatives. Quinoxaline is isomeric with other naphthyridines including quinazoline, phthalazine and cinnoline. The antitumoral properties of quinoxaline compounds have been of interest. Recently, quinoxaline and its analogs have been investigated as the catalyst’s ligands.Name: 3-Chloroquinoxalin-6-amine

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

1,2-Ethylenediols of quinoxaline and 1-phenyl-pyrazolo[o,4-b]quinoxaline was written by Binte, Hans J.;Henseke, Guenter;Bauer, Werner;Koehnke, Kurt. And the article was included in Zeitschrift fuer Chemie in 1968.Application of 5448-43-1 This article mentions the following:

Quinoxaloin (I) was acylated with Ac2O in pyridine to the diacetate, m. 232°, and with BzCl to the dibenzoate, m. 240°. Quinoxaloin diacetate was also obtained directly from quinoxaline-2-carboxaldehyde with Ac2O in pyridine at room temperature I was dehydrated by treatment with air in HCONMe2 to give quinoxalil, m. 248°. Oxidation of I with concentrated HNO3 gave quinoxaline-2-carboxylic acid, m. 212°. Quinoxalil condensed with o-H2NC6H4NH2 in CHCl3 to give 2,3-di(2-quinoxalyl)quinoxaline, m. 231°. R-substituted-quinoxaline-2-carboxaldehydes (II) reacted with KCN in 60% EtOH to give the following R-substituted quinoxaloins (R and m.p. given): 6- or 7-NO2, 297°; 6- or 7-Cl, 290-2°; 6-Cl, 295°; 7-Cl, 292°. II were prepared by HIO4 cleavage of the corresponding R-substituted 2-(D-arabino-tetrahydroxybutyl)quinoxaline. II (R = 6-Cl) formed a yellow phenylhydrazone, m. 197°, while II (R = 6- or 7-NO2) formed a red phenylhydrazone, m. 220-2°. 6(7)-Chloroquinoxaloin gave 6(7), 6′(7)-dichloroquinoxalyl, m. 321-3°, on oxidation with air and 6(7)-chloroquinoxaline-2-carboxylic acid, m. 241°, with HNO3. 7,7′-Dichloro-1,1′-diphenylflavazoin (III), m. 275°, was also prepared; diacetate m. 335-40°; dibenzoate m. 355-60°. It is also dehydrated with air to give isomeric flavazils, m. 300 and 334°. 1,1′-Diphenylflavazoin formed a bis(phenylhydrazone), m. 160°, while the flavazil (m. 300°) formed a monophenylhydrazone, m. 195-8°. The flavazil (m. 300°) reacted with o-H2NC6H4NH2 to give 2,3-bis(1-phenylpyrazolo[3,4-b]quinoxal-3-yl)quinoxaline, m. 283°. Tollens reagent is slowly reduced by I, II, and 1,1′-diphenylflavazoin, while Tillman reagent is reduced almost instantly in acid medium, but not in alk. medium. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Application of 5448-43-1).

6-Chloroquinoxaline (cas: 5448-43-1) 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.Application of 5448-43-1

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Quinoxaline N-oxides. I. The oxidation of quinoxaline and its Bz-substituted derivatives was written by Landquist, Justus K.. And the article was included in Journal of the Chemical Society in 1953.Application of 6639-82-3 This article mentions the following:

Quinoxaline (I) and its Bz-substituted-alkyl, alkoxy, halo, and acylamino derivatives are oxidized to 1- and 1,4-dioxides by organic peroxy acids. Resistance to N-oxidation is encountered in 5- and 8-substituted I. Reduction of 2,3-(O₂N)₂C₆H₃OEt with H and Raney Ni gave 3,1,2-EtOC₆H₃(NH₂)₂, oil (picrate, m. 210-12°). 2,4-Br(O₂N)C₆H₃Me nitrated with HNO₃ and H₂SO₄ at 40-5° gave 2,4,5-Br(O₂N)₂C₆H₂Me, m. 94-5°, which, treated with NH₃ in alc. 5 h. at 120° and then reduced with Zn dust and NaOH in EtOH, yielded the 4,5-(H₂N)₂ analog, m. 140-1°. The following general procedure for preparation of I derivatives was used: (CHO.NaHSO₃)₂, an ο-phenylenediamine, and H₂O were stirred 3 h. at 60°, then made alk. with KOH, and the I derivative was filtered off. The following derivatives were prepared (substituent, m.p., m.p. of 1-oxide, m.p. of 1,4-dioxide): 5-Me, 20-1°, b₁₅, 120°, 131-2°, 192-4°; 5-EtO, 63-4°, b₁₈ 165-6°, 114-16°, -; 5-Cl (II), 60-2°, 177-9°, -; 6-iodo, 114-15°, -, -; 6-NC (III), 176-8°, -, -; 6,7-Me₂, 100-1°, -, 220°; 6,7-benzo, 125-6°, -, -; 6,7-ClMe (IV), 120-2°, 166-8°, 227°; 6,7-BrMe (V), 127-8°, 167-8°, 222-4°; 6,7-Cl₂ (VI), 210°, -, 206-8°; 5,8-Cl₂ (VII), 205-7°, -, -; 6-Br (VIII)(prepared by the Sandmeyer reaction from the 6-NH₂ compound), 48-9°, b₁₈ 146-9°, -, 223-5°; 6-AcNH (prepared from the 6-NH₂ compound with Ac₂O), 196.5°, -, 245-7°; 5-AcNH, -, 175-8°, 230-2° (insufficient for anal.). The following N-oxides were also prepared (substituent, m.p. 1-oxide, m.p. 1,4-dioxide): 6-Me (IX), -, 218-19°; 5,6-benzo, 158-9°, 215-16°; 5,6:7,8-dibenzo, 243-4°, -; 5-MeO, -, 222°; 6-MeO, -, 227-8°; 6-EtO, -, 192-4°; 5,6-(MeO)₂, 138-40°, 220-2°; 6,7-(MeO)₂, -, 264-5°; 2-Cl, 150-2°, -; 6-Cl (X), 151-2°, 211-12°. I is oxidized with equimolar AcO₂H to quinoxaline 1-oxide, m. 122-3° (XI) while excess peroxy acid yields quinoxaline 1,4-dioxide, m. 241-3° (XII). Simultaneous with N-oxide formation there were obtained 2,3-dihydroxyquinoxalines which are listed below: (substituent, % yield, m.p.): IX, 1, 112°; II, 30, 142-3°; X, 15-30, 144°; VIII, 28, 132°; VII, 65, 160-1°; VI, 43, 170-70.5°; IV, 10, 172-3°; V, 12-6, 160-1°; III, 50, -; 6-O₂N, 60, 150°. XI and MeI in MeCN set aside in the dark 36 h., precipitated 1-methylquinoxalinium iodide 4-oxide, m. 188-9°. XI was added cautiously to POCl₃, and the mixture boiled 15 min. after the reaction subsided, poured on ice, made alk. with KOH, extracted with Et₂O, and concentrated to yield 2-chloroquinoxaline, m. 46-8°. Under similar conditions XII yielded 2,3-dichloroquinoxaline; 5-methylquinoxaline 1-oxide gave 2-chloro-5-methylquinoxaline, m. 95°; and 5,6-benzoquinoxaline 1-oxide yielded 2-chloro-5,6-benzoquinoxaline, m. 120.5°. 2-C₁₀H₇NHCH₂CO₂Et dissolved treated in EtOH with PhN₂Cl yielded 1,2-Ph₂NC₁₀H₆NHCH₂CO₂Et, m. 135-6°, hydrogenated with Raney Ni at 60° and 50 atm. to 1,2,3,4-tetrahydro-2-oxo-7,8-benzoquinoxaline (XIII), m. 197-8°. XIII with alk. H₂O₂ gave 2-hydroxy-7,8-benzoquinoxaline, isolated as the hydrate, m. 275-5.5°, which was converted with POCl₃ into 2-chloro-7,8-benzoquinoxaline, m. 128-9°. N-(6-nitro-o-tolyl)glycine in EtOH hydrogenated over Raney Ni at 60° and 60 atm. yielded 1,2,3,4-tetrahydro-5-methyl-2-oxoquinoxaline, m. 177-80°, readily oxidized to 2-hydroxy-5-methylquinoxaline, m. 282-3°. 2-Chloro-7,8-benzoquinoxaline and piperidine refluxed 1.5 h. gave 2-piperidino-7,8-benzoquinoxaline, m. 101.5-2.5°. 2-Piperidino-5,6-benzoquinoxaline, m. 124-5°, was similarly prepared Cl slowly passed 1 h. into 5,6-benzoquinoxaline in glacial HOAc, and the solution filtered and diluted with H₂O yielded, on purification, dichloro-5,6-benzoquinoxaline, m. 187-8°. Methylation of 2,3-dihydroxy-6-nitroquinoxaline with Me₂SO₄ gave 3-hydroxy-1-methyl-6(or 7)-nitro-2(1H)-quinoxalinone, m. 344°. 6(or 7)-Cyano-3-hydroxy-1-methyl-2(1H)-quinoxalinone, m. 353-4°, is similarly prepared In the experiment, the researchers used many compounds, for example, 6-Methoxyquinoxaline (cas: 6639-82-3Application of 6639-82-3).

6-Methoxyquinoxaline (cas: 6639-82-3) belongs to quinoxaline derivatives. Quinoxaline derivatives are important constituents of pharmacologically active compounds, including antibacterial, antibiotic and antineoplastic, antifungal, anti-inflammatory and analgesic drugs. They are well-known for application in organic light emitting devices, polymers and pharmaceutical agents. The quinoxaline-containing polymers are applicable in optical devices due to their thermal stability and low band gap.Application of 6639-82-3

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

N-Oxides of the quinoxaline series. I. N-Oxides of quinoxaline-2-carboxylic acid was written by Elina, A. S.;Magidson, O. Yu.. And the article was included in Zhurnal Obshchei Khimii in 1955.Name: Ethyl 3-chloroquinoxaline-2-carboxylate This article mentions the following:

2-(m-Nitrostyryl)quinoxaline (6.3 g.) heated to boiling in 200 ml. Me₂CO, cooled and treated with 5% aqueous KMnO₄, filtered (when colorless, the filtrate concentrated and acidified gave mixed acids which treated with 30 ml. 10% NaHCO₃ followed by 10 ml. EtOH gave Na quinoxaline-2-carboxylate, which with dilute HCl gave the free acid (I), m. 210-11°, in 56.4% yield; Et ester, m. 83-4°. To 20 g. 2-methylquinoxaline in MePh (240 ml.) was slowly added 18 g. SeO₂, the mixture refluxed 1.5 hrs., filtered, the filtrate steam distilled, and the distillate salted out gave quinoxaline-2-carboxaldehyde, which is extracted with Et₂O; the pure aldehyde, 56.6%, m. 110° (from petr. ether); the precipitate from the reaction yielded 19.8% I. The aldehyde with thiosemicarbazide in EtOH gave the thiosemicarbazone, decompose 238-9°. The aldehyde treated with KMnO₄ in Me₂CO gave 72.7% I. I Et ester (4.75 g.) added over 3 hrs. at 45° to 25 ml. AcOH, 19.2 ml. Ac₂O, and 23 ml. 30% H₂O₂ and kept 16 hrs. at 50° gave on neutralization with NaHCO₃, 80.1% yellow I 4-oxide Et ester (II), m. 156-7° (from MeOH); similar treatment of I gave I 4-oxide, 80%, m. 180-2° (from EtOH), this substance also being formed in good yield on stirring its Et ester 20 min. with 7.5% NaOH. II and alc. NH₃ kept 12 hrs. at room temperature gave I 4-oxide amide, m. 230-30.5° (from EtOH). II in EtOH with 85% N₂H₄ after 12 hrs. at room temperature gave 90% I 4-oxide hydrazide, m. 216-17° (from 50% EtOH). NH₂OH.HCl (1.64 g.) in 9 ml. MeOH treated with 1.97 g. KOH in 29 ml. MeOH, followed, at 40°, by 2 g. II and kept 20 hrs. gave K quinoxaline-2-hydroxamate 4-oxide, yellowish, m. 185-6° (from H₂O). To I 4-oxide (0.3 g.) in 3.5 ml. 15% NaOH and 22 ml. H₂O was slowly added 0.5 g. Na₂S₂O₄ and after 1 hr. at room temperature the mixture was acidified to Congo red, yielding 83.9% I. II (1 g.) and 10 ml. POCl₃ refluxed 1.5 hrs., concentrated, quenched in ice and neutralized, gave Et 3-chloroquinoxaline-2-carboxylate, m. 41.5-2° (cf. Gowenlock, et al., C.A. 40, 341.3), which heated 1.5 hrs. with Na₂CO₃ in 70% MeOH gave the corresponding free acid, m. 146-7° (decomposition); passage of NH₃ in EtOH solution of the Et ester at 0° gave 3-chloroquinoxaline-2-carboxamide, m. 214-15°. To 3 g. 2-methylquinoxaline 1,4-dioxide in C₆H₆ at reflux was added 3.5 g. SeO₂ and after 2 hrs. refluxing, the filtrate yielded 2.02 g. quinoxaline-2-carboxaldehyde 1,4-dioxide, decompose 189-90°, which gives typical aldehyde reactions and liberates iodine from acidic KI solution This on oxidation with 30% H₂O₂ in AcOH-Ac₂O at 50° 1 hr. gave I 1,4-dioxide, yellow, m. 208-9° (from AcOH); this reduced with Na₂S₂O₄ in 5% NaOH at 20-5° to I 1-oxide, colorless, m. 180-1°; this reduced with Na₂S₂O₄ in 3% NaOH to I. In the experiment, the researchers used many compounds, for example, Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0Name: Ethyl 3-chloroquinoxaline-2-carboxylate).

Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0) belongs to quinoxaline derivatives. Quinoxaline is isomeric with other naphthyridines including quinazoline, phthalazine and cinnoline. Quinoxaline and its analogues may also be formed by reduction of amino acids substituted 1,5-difluoro-2,4-dinitrobenzene (DFDNB),One study used 2-iodoxybenzoic acid (IBX) as a catalyst in the reaction of benzil with 1,2-diaminobenzene.Name: Ethyl 3-chloroquinoxaline-2-carboxylate

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider