Month: January 2023

Light-emitting properties of donor-acceptor and donor-acceptor-donor dyes in solution, solid, and aggregated states: structure-property relationship of emission behavior was written by Ishi-i, Tsutomu;Ikeda, Kei;Ogawa, Michiaki;Kusakaki, Yutarou. And the article was included in RSC Advances in 2015.Safety of 5,8-Dibromoquinoxaline This article mentions the following:

In this paper, the authors report a systematic study on the light-emitting behavior of a series of triphenylamine-based donor-acceptor-type dyes in the solution and solid states as well as in the aggregated state in polar aqueous media. The emission band shifted bathochromically along with the decrease in the fluorescence quantum yield as the solvent polarity was increased from nonpolar cyclohexane to polar DMF. In a THF/water medium, the emission was quenched in a low water volume, whereas the emission was recovered and increased in a high water volume In a low water volume, the dye mols. exist in a monomeric form, and the fluorescence quenching increases with increasing water fraction, similar to that observed in the solvent-polarity-dependence study. In contrast, the dye mols. aggregated in a high water volume This is probably because the inside of aggregates is less polar than the outside, thus preventing nonradiative deactivation and recovering the emission. This unusual emission was achieved by triphenylamine-based dyes containing a relatively strong acceptor moiety such as quinoxaline, benzothiadiazole, and thiadiazolopyridine, providing longer-wavelength red and near-IR emission. In the benzothiadiazole-based dyes, when the Ph groups in the donor moieties were replaced with Me groups, the fluorescence quantum yield decreased, indicating that the triphenylamine donor moiety is suitable for emission in the aggregated state. The nonplanar structure of triphenylamine disrupts an ordered packing and produces a less-ordered spherical aggregate, leading to an efficient light emission even in polar aqueous media. In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3Safety of 5,8-Dibromoquinoxaline).

5,8-Dibromoquinoxaline (cas: 148231-12-3) belongs to pyrazine derivatives. Pyrazines are volatile compounds that are used in the cosmetic, food, flavor, and fragrance industries. Pyrazines undergo nearly all of the same reactions as pyrimidines, from nucleophilic substitution (SNAr) to palladium-catalyzed cross coupling reactions.Safety of 5,8-Dibromoquinoxaline

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Ruthenium(II) and osmium(II) polypyridyl complexes of an asymmetric pyrazinyl- and pyridinyl-containing 1,2,4-triazole based ligand. Connectivity and physical properties of mononuclear complexes was written by Browne, Wesley R.;O’Connor, Christine M.;Hughes, Helen P.;Hage, Ronald;Walter, Olaf;Doering, Manfred;Gallagher, John F.;Vos, Johannes G.. And the article was included in Journal of the Chemical Society, Dalton Transactions in 2002.Recommanded Product: Ethyl pyrazine-2-carboxylate This article mentions the following:

The synthesis, purification and characterization of two coordination isomers of Ru(II) and Os(II) complexes containing the ligand 3-(pyrazin-2′-yl)-5-(pyridin-2”-yl)-1,2,4-triazole (Hppt) are described. The x-ray and mol. structure of [Ru(bipy)₂(ppt)]PF₆·MeOH (1a) is reported, where the Ru(bipy)₂-center is bound to the ppt^– ligand via the pyridine N and the N1 atom of the triazole ring. ¹H NMR spectroscopic measurements confirm that in the second isomer (1b) the Ru(bipy)₂-moiety is bound via the N2 atom of the triazole ring and the pyrazine ring. Partially deuterated metal complexes (d₈-bipy derivatives) were used to facilitate interpretation of ¹H NMR spectra. The redox and electronic properties indicate that there are significant differences in the electronic properties of the two coordination isomers obtained. The acid-base properties of the compounds are also reported and show that the pK_a of the 1,2,4-triazole ring varies systematically depending on the nature of the noncoordinating substituent. Anal. of these data indicates a significant electronic interaction between the pyridyl/pyrazyl rings and the 1,2,4-triazole ring in the coordinated ppt^– ligand. In the experiment, the researchers used many compounds, for example, Ethyl pyrazine-2-carboxylate (cas: 6924-68-1Recommanded Product: Ethyl pyrazine-2-carboxylate).

Ethyl pyrazine-2-carboxylate (cas: 6924-68-1) belongs to pyrazine derivatives. Pyrazine is a symmetrical molecule with point group D2h. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. A number of pyrazine-based derivatives were used as dyes or fluorescent probes.Recommanded Product: Ethyl pyrazine-2-carboxylate

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reductones and tricarbonyl compounds XXI. Reactions of dehydroascorbic acid and of other 2,3-dioxobutyrolactones with o-phenylenediamine was written by Dahn, H.;Moll, H.. And the article was included in Helvetica Chimica Acta in 1964.Category: pyrazines This article mentions the following:

2,3-Dioxo-γ-lactones react with ο-C₆H₄(NH₂) ₂ at both oxo groups and also at the lactone CO groups. Structures of condensation products were investigated. Reaction of 2 g. 4-phenyl-2,3-dioxobutyrolactone hydrate (Ia) in 200 ml. 6N HCl at room temperature with 3 g. ο-C₆H₄-(NH₂)₂ yields 96% 3-(α-hydroxybenzyl)quinoxaline-2-carboxylic acid lactone (IIa), m. 184° (aqueous Me₂CO). A suspension of 700 mg. IIa in 25 ml. MeOH is saturated at room temperature with NH₃ to yield 97% the corresponding amide, m. 152-3° (aqueous MeOH), which is readily reconverted by stirring at room temperature with 2N HCl or dilute AcOH into IIa. Refluxing I g. IIa in 25 ml. MeOH with 1 ml. PhNHNH₂ gives 1.2 g. 3-(α-hydroxybenzyl)quinoxaline-2-carboxylic acid phenylhydrazide, m. 188° (decomposition) (MeOH), which (1 g.) is refluxed in 25 ml. 2N NaOH 1 hr. under N to give BzH and 400 mg. quinoxaline-2-carboxylic acid (IV), m. 215-20° (decarboxylation) (H₂O). Refluxing 1 g. Ia with 1.1 g. O-C₆H₄(NH₂)₂ in 25 min. EtOH 25 min. gives 75% 2′-amino-3-(α-hydroxybenzyl)quinoxaline-2-carboxanilide (IIIa), m. 193-4° (decomposition), which is converted into 98% IIa by treating with 50 ml. 2N HCl 30 min. at room temperature Reaction of 1 g. IIIa with 10 ml. Ac₂O in 10 ml. HCONMe₂ (DMF) yields 81% the N-Ac derivative, m. 174-5°, which is readily hydrolyzed to IIa in 94% yield by refluxing 0.5 g. in 15 ml. EtOH and 15 ml. 2N HCl 10 min. Analogously, condensation of 2 g. 4-(p-methoxyphenyl)-2,3-dioxobutyrolactone hydrate (Ib), m. 146.8°, with 1 g. o-C₆H₄-(NH₂)₂ gives in acid medium 90% IIb, m. 165°, and in neutral EtOH 80% IIIb, m. 180° (decomposition). Dehydroascorbic acid (Ic) and 0-C₆H₄(NH₂)₂, forms in neutral solution 98% IIIc, m. 177°, which is converted in 65% yield into a yellow modification, m. 178°, by refluxing in anhydrous MeOH. Acetylation of IIIc with Ac₂O in DMF gives the corresponding N-Ac derivative, m. 191° (decomposition), which yields on hydrolysis with 0.5N HCl at 5° 60%. IIc, m. 187° (decomposition). The ir spectra of the compounds are discussed. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Category: pyrazines).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine heterocycles and their benzo derivatives possess many interesting properties, including chemical reactivity profiles, and have diverse applications in total synthesis, medicine, chemical biology, materials, dyes, and imaging. Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.Category: pyrazines

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Preparation and properties of new π-conjugated poly(quinoxaline-5,8-diyl) and poly(2,3-diethylquinoxaline-5,8-diyl). Enhancement of electron-accepting properties of poly(arylenes) by introduction of imine nitrogen was written by Kanbara, Takaki;Yamamoto, Takakazu. And the article was included in Macromolecules in 1993.Computed Properties of C8H4Br2N2 This article mentions the following:

Reactions of 5,8-dibromoquinoxaline and 5,8-dibromo-2,3-diethylquinoxaline with a 0-valent Ni complex give poly(quinoxaline-5,8-diyl) (I) and poly(2,3-diethylquinoxaline-5,8-diyl), resp. These polymers are easily converted into elec. conducting materials by chem. and electrochem. reductions Comparison of redox potentials for the n-doping and undoping of I with those of poly(naphthalene-1,4-diyl) and poly(quinoline-5,8-diyl) indicates that introduction of imine N in the recurring naphthalene-like arylene ring leads to the enhancement of the electron-accepting properties of the poly(arylene)s with change of the reducing potential by about 0.35 V per each of the imine N. In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3Computed Properties of C8H4Br2N2).

5,8-Dibromoquinoxaline (cas: 148231-12-3) belongs to pyrazine derivatives. Pyrazines are part of several biologically active polycyclic compounds; examples are quinoxalines, phenazines; and the bio-luminescent natural products pteridines, flavins, and their derivatives. Pyrazine and a variety of alkylpyrazines are flavor and aroma compounds found in baked and roasted goods. Tetramethylpyrazine (also known as ligustrazine) is reported to scavenge superoxide anion and decrease nitric oxide production in human Granulocytes.Computed Properties of C8H4Br2N2

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Pyrazine chemistry. IV. Bromination of 2-amino-3-carbomethoxypyrazine was written by Ellingson, R. C.;Henry, R. L.. And the article was included in Journal of the American Chemical Society in 1949.Quality Control of 5-Aminopyrazine-2-carboxamide This article mentions the following:

The structure of the product obtained on bromination of 2-amino-3-carbomethoxypyrazine (I) was established as 2-amino-3-carbomethoxy-5-bromopyrazine (II). I (15.3 g.) in 60 cc. warm AcOH treated dropwise with 5.4 cc. Br and 450 cc. water added after 10 min. yielded 21 g. (90.5%) II, light-yellow solid, m. 175.3-5.9°. I (61.2 g.) in 330 cc. AcOH was brominated with 21.6 cc. Br, 2 l. water and 210 g. NaOH in 400 cc. water added after 30 min., and the solution boiled 15 min., treated with C, filtered, and cooled, yielding 90.5 g. Na 3-amino-6-bromopyrazinoate (C.A. numbering) which, when dissolved in 2400 cc. warm water, acidified with 60 cc. 40% HBr, and cooled, yielded 64 g. light-brown crystals of 3-amino-6-bromopyrazinoic acid (III), m. 185-6° (decomposition) (from water). A suspension of 59.6 g. crude III in 600 cc. dry tetrahydronaphthalene was refluxed 30 min., treated (hot) with C, the filtrate was chilled, and the crystals which separated were washed in petr. ether, yielding 38.4 g. 2-amino-5-bromopyrazine (IV), m. 113.6° (corrected). IV (4.0 g.), 2 g. CuCN, 3.0 g. KCN, 14.0 cc. water, and 6.0 cc. EtOH sealed in a Carius tube were heated at 170° for 16 h., then rinsed out with 400 cc. water, the suspension acidified with HCl, boiled to remove the HCN, and the Cu removed with H₂S; the cooled filtrate deposited 1.55 g. of a mixture of the amide and 6-aminopyrazinoic acid (V). The mixture was suspended in 50 cc. of 2% NaOH; the insoluble fraction (0.7 g.), 2-amino-5-carbamylpyrazine, m. 277-9° (from water). The alk. filtrate acidified with HCl gave 0.55 g. V, m. 278° (from water). Br (15.2 cc.) was added dropwise (temperature kept below 0°) to 15.3 g. I in 57 cc. 48% HBr, then 17.4 g. NaNO₂ in 30 cc. water (temperature below 0°), and finally 38 g. NaOH in 100 cc. water; next day 5.6 g. light-brown solid was collected and an addnl. 3.8 g. was obtained by extraction with EtOAc. Crystallization from 100 cc. water and 32 cc. EtOH gave 7.4 g. 2-bromo-3-carbomethoxypyrazine (VI), m. 44° (corrected). VI (3 g.), 2.5 g. CuCN, 1 g. KCN, 7 cc. EtOH, and 12 cc. water sealed in a Carius tube were heated 16 h. at 125°, the filtered suspension made alk., boiled 1 h., 10 cc. of a 25% solution of BaCl₂ added, the Ba salt collected, the Ba removed with H₂SO₄, and the filtrate concentrated to give (on cooling) tan crystals (VII), m. 171-5° (decomposition). VII (0.55 g.) in 5 cc. MeOH and 5 cc. H₂SO₄ was refluxed 15 h., the mixture diluted with water, made alk. with Na₂CO₃, extracted with EtOAc, and the extract dried, filtered, and evaporated to dryness, yielding 0.4 g. 2,3-dicarbomethoxypyrazine (VIII), m. 55-6°. To 29 cc. 48% HBr (cooled, ice-NaCl) were added consecutively 8.7 g. IV, 7.6 cc. Br, 8.7 g. NaNO₂ in 15 cc. water, and 19 g. NaOH in 50 cc. water to give 7.8 g. 2,5-dibromopyrazine (IX), m. 47-8° (from water-EtOH, 2:1). 2,5-Dicarbomethoxypyrazine, prepared from IX by a method similar to that used for the preparation of VIII, m. 169.5-70.1° (from MeOH). In the experiment, the researchers used many compounds, for example, 5-Aminopyrazine-2-carboxamide (cas: 89323-09-1Quality Control of 5-Aminopyrazine-2-carboxamide).

5-Aminopyrazine-2-carboxamide (cas: 89323-09-1) belongs to pyrazine derivatives. Pyrazines are volatile compounds that are used in the cosmetic, food, flavor, and fragrance industries. A number of pyrazine-based derivatives were used as dyes or fluorescent probes.Quality Control of 5-Aminopyrazine-2-carboxamide

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Azaquinoxalines was written by Bodforss, Sven. And the article was included in Justus Liebigs Annalen der Chemie in 1964.Application of 322-46-3 This article mentions the following:

A series of azaquinoxalines was prepared from 2,3-diaminopyridine (I) with α-dicarbonyl compounds Equivalent amounts of PhCH:CHCOCO₂H (II) and I in EtOH yielded the I-II salt, decompose 144° (EtOH or hot H₂O). I-II salt refluxed about 10 min. in AcOH gave about 20% 2-styryl-5(or 8)-aza-3-quinoxalone (III), 251° (AcOH). The ο-NO₂ derivative (2 g.) of II and 1 g. I refluxed 4 hrs. in AcOH and EtOH yielded the 2-(ο-O₂NC₆H₄CH:CH) analog of III, decompose 275° (HCONMe₂). BzCH₂COCO₂H and I (equimolar amounts) mixed in EtOH, and the resulting salt refluxed in AcOH gave quant. the 2-BzCH₂ analog (IV) of III, ∼283° (AcOH). IV (2 g.) in 20 g. concentrated H₂SO₄ and 2.5 g. P₂O₅ heated 2 days at 100° yielded 2-phenyl-5-azafuro[2,3b]quinoxaline (V), m. 251° (AcOH), and some SO₃H derivative (VI) of V which was isolated as the pyridinium salt; the salt in H₂O treated with dilute HCl gave VI. III (2.3 g.) in CHCl₃ treated slowly in sunlight with 1.6 g. Br in AcOH, and the resulting crude dibromide refluxed with 10 cc. dry C₅H₅N gave VII (X = Br), which was dissolved in H₂O and treated with NaClO₄ to give VII (X = ClO₄), brown-yellow microcrystals. I (2.3 g.) and 15 cc. (CO₂Et)₂ refluxed 1 hr. gave quant. 2,3-dihydroxy-5-azaquinoxaline, decompose above 300°. I (2 g.) and 4 g. Bz₂ refluxed 12 hrs. with a few drops concentrated H₂SO₄ yielded 2,3-diphenyl-5-azaquinoxaline (VIII), m. 144°. (p-HOC₆H₄CO)₂ (2 g.) and 1 g. I refluxed 2 days with 20 cc. EtOH and 2 cc. AcOH gave the bis(p-HOC₆H₄) analog of VIII, decompose 315°. I (2 g.) and 5 g. alloxan in EtOH-AcOH yielded alloxan-3(or 2)-[2(or 3)-aminopyridyl)imide, decompose ∼250° (reprecipitated from NH₄OH with AcOH). Alloxan anil refluxed 2 days with 4N KOH, adjusted to about pH 10, and acidified with dilute HCl yielded 2-carboxy-3-hydroxy-5(or 8)-azaquinoxaline, decompose ∼280°, which dissolved in hot H₂O and reprecipitated with HCl gave an unidentified, brown-red solid, decomposing above 345°. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Application of 322-46-3).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine is an N-heterocyclic moiety, and it can be easily prepared from ethylenediamine and 1,2-diketone, α-hydroxyketone, α-methyl ketone. A number of pyrazine-based derivatives were used as dyes or fluorescent probes.Application of 322-46-3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Copolymers of Cyclopentadithiophene and Electron-Deficient Aromatic Units Designed for Photovoltaic Applications was written by Bijleveld, Johan C.;Shahid, Munazza;Gilot, Jan;Wienk, Martijn M.;Janssen, Rene A. J.. And the article was included in Advanced Functional Materials in 2009.SDS of cas: 148231-12-3 This article mentions the following:

Alternating copolymers based on cyclopentadithiophene (CPDT) and five different electron-deficient aromatic units with reduced optical band gaps are synthesized via Suzuki coupling. All polymers show a significant photovoltaic response when mixed with a fullerene acceptor. The frontier orbital levels of the new polymers are designed to minimize energy losses by increasing the open-circuit voltage with respect to the optical band gap, while maintaining a high coverage of the absorption with the solar spectrum. The best cells are obtained for a copolymer of CPDT and benzooxadiazole (BO) with a band gap of 1.47 eV. This cell gives a short-circuit current of 5.4 mA cm^-2, an open-circuit voltage of 0.78 V, and a fill factor of 0.6, resulting in a power conversion efficiency of about 2.5%. In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3SDS of cas: 148231-12-3).

5,8-Dibromoquinoxaline (cas: 148231-12-3) belongs to pyrazine derivatives. Pyrazinesare six-membered aromatic heterocyclic organic compounds with two nitrogen atoms at 1,4-positions. Pyrazine is a weaker base (pKb = 13.4) than pyridine (pKb = 8.8), pyrimidine (pKb = 12.7). Substituted pyrazines have been found as subunits of multiple synthetically constructed therapeutic agents, as well as several natural products.SDS of cas: 148231-12-3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Rational design for cooperative recognition of specific nucleobases using β-cyclodextrin-modified DNAs and fluorescent ligands on DNA and RNA scaffolds was written by Futamura, Akika;Uemura, Asuka;Imoto, Takeshi;Kitamura, Yusuke;Matsuura, Hirotaka;Wang, Chun-Xia;Ichihashi, Toshiki;Sato, Yusuke;Teramae, Norio;Nishizawa, Seiichi;Ihara, Toshihiro. And the article was included in Chemistry – A European Journal in 2013.Application In Synthesis of Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate This article mentions the following:

The authors propose a binary fluorimetric method for DNA and RNA anal. by the combined use of two probes rationally designed to work cooperatively. One probe is an oligonucleotide (ODN) conjugate bearing a β-cyclodextrin (β-CyD). The other probe is a small reporter ligand, which comprises linked mols. of a nucleobase-specific heterocycle and an environment-sensitive fluorophore. The heterocycle of the reporter ligand recognizes a single nucleobase displayed in a gap on the target labeled with the conjugate and, at the same time, the fluorophore moiety forms a luminous inclusion complex with nearby β-CyD. Three reporter ligands, MNDS (naphthyridine-dansyl linked ligand), MNDB (naphthyridine-DBD), and DPDB (pyridine-DBD), were used for DNA and RNA probing with 3′-end or 5′-end modified β-CyD-ODN conjugates. For the DNA target, the β-CyD tethered to the 3′-end of the ODN facing into the gap interacted with the fluorophore sticking out into the major groove of the gap site (MNDS and DPDB). Meanwhile the β-CyD on the 5′-end of the ODN interacted with the fluorophore in the minor groove (MNDB and DPDB). The results obtained by this study could be a guideline for the design of binary DNA/RNA probe systems based on controlling the proximity of functional mols. In the experiment, the researchers used many compounds, for example, Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate (cas: 1458-01-1Application In Synthesis of Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate).

Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate (cas: 1458-01-1) belongs to pyrazine derivatives. Pyrazines are part of several biologically active polycyclic compounds; examples are quinoxalines, phenazines; and the bio-luminescent natural products pteridines, flavins, and their derivatives. Pyrazines are chemical compounds (technically called “methoxypyrazines”) found in grape skin and stems that are responsible for many “green” flavors in wine. Levels of pyrazines are dependent on viticultural practices, climate, and grape variety.Application In Synthesis of Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Method of predicting the site of alkylation of heterocyclic polyazines from kinetic data on model compounds was written by Zoltewicz, J. A.;Deady, L. W.. And the article was included in Tetrahedron in 1972.Synthetic Route of C7H5N3 This article mentions the following:

A method is presented which enables calculation of isomer ratios resulting from the N-methylation of polyazines in Me2SO. The method assumes that substituent and annular N atom effects on reactivity are additive in the absence of steric factors. Kinetic studies on model azines provide rate factors which are employed in the calculations Observed and calculated isomer ratios are compared for a number of polyazines. An extension to N-oxidation is suggested. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Synthetic Route of C7H5N3).

Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazines are part of several biologically active polycyclic compounds; examples are quinoxalines, phenazines; and the bio-luminescent natural products pteridines, flavins, and their derivatives. Pyrazines are chemical compounds (technically called “methoxypyrazines”) found in grape skin and stems that are responsible for many “green” flavors in wine. Levels of pyrazines are dependent on viticultural practices, climate, and grape variety.Synthetic Route of C7H5N3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Simple Access to Sol-Gel Precursors Bearing Fluorescent Aromatic Core Units was written by Hemgesberg, Maximilian;Ohlmann, Dominik M.;Schmitt, Yvonne;Wolfe, Monique R.;Mueller, Melanie K.;Erb, Benjamin;Sun, Yu;Goossen, Lukas J.;Gerhards, Markus;Thiel, Werner R.. And the article was included in European Journal of Organic Chemistry in 2012.SDS of cas: 148231-12-3 This article mentions the following:

Di-, tri-, and tetrathienyl-substituted polycyclic aromatic fluorophores were prepared from different aryldi-, aryltri-, or aryltetrahalides by a simple and fast Suzuki coupling. The reaction was optimized for the synthesis of the desired materials on multigram scale. The coupled products were converted into the corresponding iodides through iodination with N-iodosuccinimide. The iodides turned out to be versatile starting materials for applications, such as periodic mesoporous organosilica syntheses. They were converted into a variety of new trimethoxysilyl arenes by using a very efficient Pd-mediated C-Si cross-coupling, which was also extended to the corresponding thienyl bromides by using a dimeric Pd(I) catalyst. All compounds were characterized by ¹H NMR, ¹³C NMR, ²⁹Si NMR, and ATR-IR spectroscopy and HRMS. In the experiment, the researchers used many compounds, for example, 5,8-Dibromoquinoxaline (cas: 148231-12-3SDS of cas: 148231-12-3).

5,8-Dibromoquinoxaline (cas: 148231-12-3) belongs to pyrazine derivatives. Pyrazine is a symmetrical molecule with point group D2h. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. A large number of pyrazine derivatives are known for their antitumor, antibiotic, anticonvulsant, antituberculosis, and diuretic activities.SDS of cas: 148231-12-3

Referemce:
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem