Heterocyclic Building Blocks-quinoxaline

A novel near-infrared fluorescent probe with large stokes shifts for sensing extreme acidity and its application in bioimaging was written by Gong, Jin;Liu, Chang;Jiao, Xiaojie;He, Song;Zhao, Liancheng;Zeng, Xianshun. And the article was included in Spectrochimica Acta, Part A: Molecular and Biomolecular Spectroscopy in 2020.Name: 6-Methoxyquinoxaline This article mentions the following:

The authors reported a novel near-IR (NIR) fluorescent probe RQNN (I) with large Stokes shift (98 nm) for monitoring pH under extremely acidic conditions. For the preparation of this probe, a 1,4-diethylpiperazine moiety was introduced in rhodamine scaffold to tune the electron-donating character, and an o-phenylenediamine was introduced in spironolactone to provide larger steric hindrance. The deprotonated-protonated equilibrium between RQNN, RQNN-H⁺ and RQNN-H²⁺ were evaluated in different pH by absorption and emission spectra. As expected, RQNN exhibited lower pk_a values (pk_a1 = 4.83, pk_a2 = 2.99), indicating that the probe can be used in extremely acidic pH. Moreover, RQNN possessed highly selective response to H⁺ over essential metal ions and biol. related redox mols., high photo-stability, rapid response time, and excellent reversibility. Importantly, the probe had excellent cell membrane permeability and was further applied successfully to monitor pH fluctuations in live cells. In the experiment, the researchers used many compounds, for example, 6-Methoxyquinoxaline (cas: 6639-82-3Name: 6-Methoxyquinoxaline).

6-Methoxyquinoxaline (cas: 6639-82-3) belongs to quinoxaline derivatives. Quinoxalines are important class of heterocyclic compounds, associated with wider pharmacological applications. Quinoxalines are used in the treatment of bacterial, cancer, and HIV infections. Moreover, varenicline, a clinical drug is used for treating nicotine addiction, also contains quinoxaline moiety.Name: 6-Methoxyquinoxaline

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Topical mosquito repellents. IX: quinolines, isoquinolines, and quinoxalines was written by Skinner, W. A.;Crawford, H. T.;Tong, H.;Skidmore, D.;Maibach, H. I.. And the article was included in Journal of Pharmaceutical Sciences in 1976.Safety of 6-Chloroquinoxaline This article mentions the following:

Various quinoxalines I, quinolines II, and isoquinolines III were evaluated for their effectiveness as topical mosquito repellents. Several tetrahydroquinolines and isoquinolines also were included. None of the compounds tested was superior to diethyltoluamide. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Safety of 6-Chloroquinoxaline).

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. Quinoxalines are used in the treatment of bacterial, cancer, and HIV infections. Moreover, varenicline, a clinical drug is used for treating nicotine addiction, also contains quinoxaline moiety.Safety of 6-Chloroquinoxaline

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

12H-[1]Benzopyrano[2,3-b]quinoxalinone synthesis was written by Vinot, Nicole;Maitte, Pierre. And the article was included in Journal of Heterocyclic Chemistry in 1982.Reference of 49679-45-0 This article mentions the following:

3-Benzyl-2-quinoxalinoes (I) were obtained by condensation of o-(H₂N)₂C₆H₄ with phenylpyruvic acids. I were easily substituted in position 2, which permitted the preparation of many derivatives; however, cyclization of I into 12H-[1]benzopyrano[2,3-b]quinoxalines failed. This new hetercycle was synthesized from Et-2-phenoxy-3-quinoxalinecarboxylate. In the experiment, the researchers used many compounds, for example, Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0Reference of 49679-45-0).

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.Reference of 49679-45-0

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

The polarography of quinoxaline. II. 6-Substituted derivatives was written by Strier, Murray P.;Cavagnol, J. C.. And the article was included in Journal of the American Chemical Society in 1958.COA of Formula: C8H5ClN2 This article mentions the following:

The reduction of 6-amino-, 6-bromo-, 6-chloro-, 6-ethoxy-, and 6-methoxyquinoline at the dropping Hg electrode is similar to that for quinoxaline. Two waves were found at pH values of 2, 4, and 6 whereas the 1st major wave occurred at pH 8 and 10. The 1st wave represents reduction to the 1,4-dihydro stage. At pH 2 the differentiated nature of the wave is indicative of a bimol. reduction in 2 successive 1-electron steps. At higher pH values the reduction was directly to the dihydroquinoxaline. For 6-aminoquinoxaline the latter occurred at all pH values. The 2nd wave is due to evolution of H catalyzed by the 1,4-dihydroquinozalinium ion. Though the criterion for polarographic reversibility was not established, Hammett’s equation was found to be applicable to the 1st wave throughout the pH range studied. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1COA of Formula: C8H5ClN2).

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.COA of Formula: C8H5ClN2

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Structure-based design of novel quinoxaline-2-carboxylic acids and analogues as Pim-1 inhibitors was written by Oyallon, Bruno;Brachet-Botineau, Marie;Loge, Cedric;Bonnet, Pascal;Souab, Mohamed;Robert, Thomas;Ruchaud, Sandrine;Bach, Stephane;Berthelot, Pascal;Gouilleux, Fabrice;Viaud-Massuard, Marie-Claude;Denevault-Sabourin, Caroline. And the article was included in European Journal of Medicinal Chemistry in 2018.Formula: C11H9ClN2O2 This article mentions the following:

We identified a new series of quinoxaline-2-carboxylic acid derivatives, targeting the human proviral integration site for Moloney murine leukemia virus-1 (HsPim-1) kinase. Seventeen analogs were synthesized providing useful insight into structure-activity relationships studied. Docking studies realized in the ATP pocket of HsPim-1 are consistent with an unclassical binding mode of these inhibitors. The lead compound I was able to block HsPim-1 enzymic activity at nanomolar concentrations (IC₅₀ of 74 nM), with a good selectivity profile against a panel of mammalian protein kinases. In vitro studies on the human chronic myeloid leukemia cell line KU812 showed an antitumor activity at micromolar concentrations As a result, compound I represents a promising lead for the design of novel anticancer targeted therapies. In the experiment, the researchers used many compounds, for example, Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0Formula: C11H9ClN2O2).

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-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: C11H9ClN2O2

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.Quality Control of 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: 49679-45-0Quality Control of Ethyl 3-chloroquinoxaline-2-carboxylate).

Ethyl 3-chloroquinoxaline-2-carboxylate (cas: 49679-45-0) 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.Quality Control of Ethyl 3-chloroquinoxaline-2-carboxylate

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Proton resonance spectra of heterocycles. IV. Quinoxaline and monosubstituted quinoxalines was written by Brignell, Peter J.;Katritzky, Alan R.;Reavill, Roger E.;Cheeseman, Gordon W. H.;Sarsfield, A. A.. And the article was included in Journal of the Chemical Society [Section] B: Physical Organic in 1967.Computed Properties of C8H5ClN2 This article mentions the following:

Chem. shifts and coupling constants are reported for fourteen monosubstituted quinoxalines. These parameters are correlated with the effect of the substituents on the electron distribution. 16 references. 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. Condensed heterocycles of quinoxalines have become attractive targets in synthetic and medicinal chemistry due to their significant biological activities. Quinoxalines are used in the treatment of bacterial, cancer, and HIV infections. Moreover, varenicline, a clinical drug is used for treating nicotine addiction, also contains quinoxaline moiety.Computed Properties of C8H5ClN2

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

A novel near-infrared fluorescent probe for highly selective recognition of hydrogen sulfide and imaging in living cells was written by Zhong, Keli;Deng, Longlong;Zhao, Jie;Yan, Xiaomei;Sun, Tong;Li, Jianrong;Tang, Lijun. And the article was included in RSC Advances in 2018.Electric Literature of C9H8N2O This article mentions the following:

A novel near-IR fluorescent probe (L) based on a 1,4-diethyl-1,2,3,4-tetrahydro-7H-pyrano[2,3-g]quinoxalin-7-one scaffold has been synthesized and characterized. Probe L displays highly selective and sensitive recognition to H₂S over various anions and biol. thiols with a large Stokes shift (125 nm) in THF/H₂O (6/4, volume/volume, Tris-HCl 10 mM, pH = 7.4). This probe exhibits turn-on fluorescence for H2S through HS- induced thiolysis of dinitrophenyl ether. Confocal laser scanning micrographs of MCF-7 cells incubated with L confirm that L is cell-permeable and can successfully detect H₂S in living cells. 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 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. Quinoxalines are used in the treatment of bacterial, cancer, and HIV infections. Moreover, varenicline, a clinical drug is used for treating nicotine addiction, also contains quinoxaline moiety.Electric Literature of C9H8N2O

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

PAd2-DalPhos Enables the Nickel-Catalyzed C-N Cross-Coupling of Primary Heteroarylamines and (Hetero)aryl Chlorides was written by Clark, Jillian S. K.;Ferguson, Michael J.;McDonald, Robert;Stradiotto, Mark. And the article was included in Angewandte Chemie, International Edition in 2019.Computed Properties of C8H5ClN2 This article mentions the following:

Base-metal catalysts capable of enabling the assembly of heteroatom-dense mols. by cross-coupling of primary heteroarylamines and (hetero)aryl chlorides, while sought-after given the ubiquity of unsym. di(hetero)arylamino fragments in pharmacophores, are unknown. Herein, we disclose the new “double cage” bisphosphine PAd2-DalPhos (L2). The derived air-stable Ni^II pre-catalyst C2 functions well at low loadings in challenging test C-N cross-couplings with established substrates, and facilitates the first Ni-catalyzed C-N cross-couplings of primary five- or six-membered ring heteroarylamines and activated (hetero)aryl chlorides, with synthetically useful scope that is competitive with Pd catalysis. 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. Condensed heterocycles of quinoxalines have become attractive targets in synthetic and medicinal chemistry due to their significant biological activities. 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.Computed Properties of C8H5ClN2

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Versatile (Pentamethylcyclopentadienyl)rhodium-2,2′-Bipyridine (Cp*Rh-bpy) Catalyst for Transfer Hydrogenation of N-Heterocycles in Water was written by Zhang, Lingjuan;Qiu, Ruiying;Xue, Xiao;Pan, Yixiao;Xu, Conghui;Li, Huanrong;Xu, Lijin. And the article was included in Advanced Synthesis & Catalysis in 2015.Reference of 5448-43-1 This article mentions the following:

A study employing the catalytic system consisting of (pentamethylcyclopentadienyl)rhodium dichloride dimer [Cp*RhCl₂]₂ and 2,2′-bipyridine (bpy) for transfer hydrogenation of a variety of quinoxalines, quinoxalinones, quinolines and indoles under aqueous conditions with formate as the hydrogen source is reported. This approach provides various tetrahydroquinoxalines, dihydroquinoxalinones, tetrahydroquinolines and indolines in good to excellent yields. The activity of the catalyst towards quinoxalines and quinoxalinones is excellent, with a substrate to catalyst ratio (S/C) of 10000 being feasible. The choice of ligand is critical to the catalysis, and the aqueous phase reduction is highly pH-dependent, with acidic pH values needed for optimal reduction The catalyst is easy to access, and the reaction is operationally simple without requiring an inert atm. In the experiment, the researchers used many compounds, for example, 6-Chloroquinoxaline (cas: 5448-43-1Reference of 5448-43-1).

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.Reference of 5448-43-1

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider