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Photochemical hydroxylation of quinoxalines was written by Verbeek, J.;Berends, W.;Van Beek, H. C. A.. And the article was included in Recueil des Travaux Chimiques des Pays-Bas in 1976.Quality Control of 6-Methoxyquinoxaline This article mentions the following:

Irradiation of quinoxaline (I) in acidic aqueous solution under anaerobic conditions gave 5-hydroxyquinoxaline (II) and the 1,4-dihydroquinoxaline radical cation (III). III was characterized by ESR spectroscopy. Under aerobic conditions II is the only irradiation product formed. The effect of substituents attached to the benzene nucleus of I is analyzed. In the experiment, the researchers used many compounds, for example, 6-Methoxyquinoxaline (cas: 6639-82-3Quality Control of 6-Methoxyquinoxaline).

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. 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.Quality Control of 6-Methoxyquinoxaline

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Nickel-Catalyzed N-Arylation of Cyclopropylamine and Related Ammonium Salts with (Hetero)aryl (Pseudo)halides at Room Temperature was written by Tassone, Joseph P.;MacQueen, Preston M.;Lavoie, Christopher M.;Ferguson, Michael J.;McDonald, Robert;Stradiotto, Mark. And the article was included in ACS Catalysis in 2017.Reference of 5448-43-1 This article mentions the following:

Whereas the metal-catalyzed C(sp2)-N cross-coupling of cyclopropylamine with aryl electrophiles represents an attractive route to pharmaceutically relevant N-arylcyclopropylamines, few catalysts that are capable of effecting such transformations have been identified. Herein, the nickel-catalyzed C(sp2)-N cross-coupling of cyclopropylamine and related nucleophiles, including ammonium salts, with (hetero)aryl (pseudo)halides is reported for the first time, with the demonstrated scope of reactivity exceeding that displayed by all previously reported catalysts (Pd, Cu, or other). Our preliminary efforts to effect the N-arylation of cyclopropylamine with (hetero)aryl chlorides at room temperature by use of (L)NiCl(o-tolyl) pre-catalysts (L = PAd-DalPhos, C1; L = JosiPhos CyPF-Cy, C2) were unsuccessful, despite the established efficacy of C1 and C2 in transformations of other primary alkylamines. However, systematic modification of the ancillary ligand (L) structure enabled success in such transformations, with new and crystallog. characterized (L)NiCl(o-tolyl) pre-catalysts incorporating o-phenylene-bridged bisphosphines featuring either phosphatrioxaadamantane and PCy2 (L = L3, CyPAd-DalPhos; C3), P(o-tolyl)2 and P(t-Bu)2 (L = L4; C4), or PCy2 and P(t-Bu)2 (L = L5; C5) donor pairings proving to be particularly effective. In employing the air-stable pre-catalyst C3 in cross-couplings of cyclopropylamine, substituted electrophiles encompassing an unprecedentedly broad range of heteroaryl (pyridine, isoquinoline, quinoline, quinoxaline, pyrimidine, purine, benzothiophene, and benzothiazole) and (pseudo)halide (chloride, bromide, mesylate, tosylate, triflate, sulfamate, and carbamate) structures were employed successfully, in the majority of cases under mild conditions (3 mol% Ni, 25°). Preliminary studies also confirmed the ability of C3 to effect the N-arylation of cyclopropanemethylamine hydrochloride and cyclobutylamine hydrochloride under similar conditions. A notable exception in this chem. was observed specifically in the case of electron-rich aryl chlorides, where the use of C4 in place of C3 proved more effective. In keeping with this observation, catalyst inhibition by 4-chloroanisole was observed in the otherwise efficient cross-coupling of cyclopropylamine and 3-chloropyridine when using C3. Competition studies involving C3 revealed a (pseudo)halide reactivity preference (Cl > Br, OTs). 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. 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. The antitumoral properties of quinoxaline compounds have been of interest. Recently, quinoxaline and its analogs have been investigated as the catalyst’s ligands.Reference of 5448-43-1

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Safety of (S)-Propane-1,2-diamine dihydrochloride. Aromatic heterocyclic compounds can also be classified according to the number of heteroatoms contained in the heterocycle: single heteroatom, two heteroatoms, three heteroatoms and four heteroatoms. Compound: (S)-Propane-1,2-diamine dihydrochloride, is researched, Molecular C3H12Cl2N2, CAS is 19777-66-3, about Utilization of an enantiomer as a solution to a pharmaceutical problem: application to solubilization of 1,2-bis(4-piperazine-2,6-dione)propane. Author is Repta, A. J.; Baltezor, M. J.; Bansal, P. C..

An enantiomer (R)(-)-I [24613-06-7] of the cytotoxic agent (±)-1,2-bis(4-piperazine-2,6-dione)propane [(±)-I] (ICRF 159) [21416-67-1] was utilized to overcome a solubility problem in the preparation of a solution suitable for i.v. use. The enantiomers (S)(+)-I [24584-09-6] and (R)(-)-I were prepared and were about five times more soluble and melted at about 40° lower than the racemic compound This study appears to be the 1st reported instance in which the difference in the phys. properties of a racemic compound and its enantiomers was utilized to improve a pharmaceutical formulation. The expected differences in the phys. properties of racemic solids and their corresponding enantiomers are discussed briefly in relation to the 3 racemic modifications known to exist.

In addition to the literature in the link below, there is a lot of literature about this compound((S)-Propane-1,2-diamine dihydrochloride)Safety of (S)-Propane-1,2-diamine dihydrochloride, illustrating the importance and wide applicability of this compound(19777-66-3).

Reference:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider