Pyrazines

873-40-5, Each compound has different characteristics, and only by selecting the characteristics of the compound suitable for a specific situation can the compound be applied on a large scale. 873-40-5, name is 2,3,5-Trichloropyrazine, This compound has unique chemical properties. The synthetic route is as follows.

General procedure: Under nitrogen gas stream 2,3,5-trichloropyrazine of 28g (152.65mmol),2-chlorophenylboronic acid of 23.8g (152.65mmol),Put THF / H2O and K2CO3 of 800ml / 200ml 63.3g (457.9mmol) and stirred. At 40 into the Pd (PPh3) 4 of 5.3g (4.58mmol) was stirred at 80 for 12 hours.After completion of the reaction, which was then extracted with dichloromethane. The organic layer was dried over MgSO4 filtered under reduced pressure. The filtered organic layer was evaporated under reduced pressure to a back by column chromatography the desired compound 2,5-dichloro-3- (2-chlorophenyl) pyrazine 12g (yield: 30%) was obtained.

If you are interested in these compounds, you can also browse my other articles.Thank you for taking the time to read this article. I hope you enjoyed it.

Reference:
Patent; Doosan Corporation; Kim, Tae Hyung; Bae, Hyung Chan; Son, Hyo Suk; Baek, Young Mi; Patk, Ho Chul; (54 pag.)KR101488560; (2015); B1;,
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24241-18-7, Adding some certain compound to certain chemical reactions, such as: 24241-18-7, name is 2-Amino-3,5-dibromopyrazine, can increase the reaction rate and produce products with better performance than those obtained under traditional synthetic methods. Here is a downstream synthesis route of the compound 24241-18-7.

The suspension of 18b (2.51 g, 10.0 mmol), NaCN (0.59 g,12.0 mmol), CuI (0.95 g, 5.0 mmol) and Pd(PPh3)4 (0.14 g,0.1 mmol) were stirred in DMF (20 mL) at 120 C for 10 h under nitrogen protection. After cooling to room temperature, 10% aqueous solution of Na2S2O3(10 mL) and water(50 mL) were added. The mixture was extracted with ethyl acetate (50 mL ¡Á 3), washed with water (3 ¡Á 50 mL), dried over anhydrous Na2SO4 and concentrated. The residue was purified by chromatography on silica gel eluting with PE/EA (10:1-2:1) to give an off-white solid (1.1 g, yield 55%). 6-Bromo-3-aminopyrazine-2-carbonitrile (19b)Yield: 55%, off-white solid, M.p.: 180-182 C (Lit.183-184 C, Sato et al. 1990a, b). 1H NMR (400 MHz,DMSO-d6): delta 8.45 (s, 1H), 7.62 (s, 2H). 1H NMR (400 MHz,CDCl3):delta 8.30 (s, 1H), 5.28 (s, 2H). 13C NMR (125 MHz,DMSO-d6): delta 156.70, 150.49, 123.64, 115.45, 110.60. EI-MS m/z: 198 (M+, Br79,100), 200 (M+, Br81,98), 171(M+, Br79,-H, -CN, 17), 173 (M+, Br81,-H, -CN, 17),119(M+, -Br, 32), 92 (M+, -Br, -H, -CN, 46).

Chemical properties determine the actual use. Each compound has specific chemical properties and uses. We look forward to more synthetic routes in the future to expand reaction routes of 24241-18-7.

Reference:
Article; Guo, Qi; Xu, Mingshuo; Guo, Shuang; Zhu, Fuqiang; Xie, Yuanchao; Shen, Jingshan; Chemical Papers; vol. 73; 5; (2019); p. 1043 – 1051;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 4858-85-9 name is 2,3-Dichloropyrazine, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below. 4858-85-9

Preparation of 2-Amino-3-Chloropyrazine A mixture of 2,3-dichloropyrazine (Lancaster) and ammonium hydroxide was heated in a sealed tube at 100 C. for 24 h resulting in a white precipitate. The precipitate was collected by filtration and dried under vacuum to afford 2-amino-3-chloropyrazine of sufficient purity for immediate conversion to 2-chloro-3-nitropyrazine.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 2,3-Dichloropyrazine, and friends who are interested can also refer to it.

Reference:
Patent; Konradi, Andrei W.; Pleiss, Michael A.; Thorsett, Eugene D.; Ashwell, Susan; Welmaker, Gregory S.; Kreft, Anthony; Sarantakis, Dimitrios; Dressen, Darren B.; Grant, Francine S.; Semko, Christopher; Xu, Ying-Zi; Stappenbeck, Frank; US2002/52375; (2002); A1;,
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In the next few decades, the world population will flourish. As the population grows rapidly and people all over the world use more and more resources, all industries must consider their environmental impact. 1458-01-1, name is Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate belongs to Pyrazines compound, it is a common compound, a new synthetic route is introduced below. 1458-01-1

General procedure: Methyl 3,5-diamino-6-chloropyrazine-2-carboxylate 2 (1 eq.) was combined with K2CO3 (10 eq.), the appropriate (het)aryl boronic acid (1.5 eq.) and Pd(PPh3)4 (5 mol%) in a two-neck round bottom flask. The flask was connected to a condenser and purged with nitrogen. A 4:1 mixture of anhydrous toluene: MeOH (60 mL) was added via syringe and the reaction mixture was heated at reflux for 0.5-18 h. The mixture was allowed to cool to room temperature and filtered through Celite (10 x 3 cm, eluting with 3 x 20 mL EtOAc). The filtrate was evaporated to dryness and the residue purified by silica gel flash column chromatography using EtOAc/pet spirit.

The synthetic route of 1458-01-1 has been constantly updated, and we look forward to future research findings.

Reference:
Article; Buckley, Benjamin J.; Majed, Hiwa; Aboelela, Ashraf; Minaei, Elahe; Jiang, Longguang; Fildes, Karen; Cheung, Chen-Yi; Johnson, Darren; Bachovchin, Daniel; Cook, Gregory M.; Huang, Mingdong; Ranson, Marie; Kelso, Michael J.; Bioorganic and Medicinal Chemistry Letters; vol. 29; 24; (2019);,
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Pyrazine | C4H4N2 – PubChem

Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 24241-18-7, name is 2-Amino-3,5-dibromopyrazine, A new synthetic method of this compound is introduced below., 24241-18-7

Magnesium turnings (293.9mg, 12.1mmol, 3.0equiv) and I2 (153.6mg, 605mumol, 0.15equiv) were added to a dry 100-mL 2-necked round-bottom flask under an argon atmosphere. Freshly distilled THF (25mL) was added using a syringe. The mixture was stirred at 0¡ãC until the brown color of the I2 disappeared. Then, benzylbromide (1.44mL, 12.1mmol, 3.0equiv) was slowly added using a syringe. After 10min ZnCl2 was added and the mixture was stirred for 40min. To this mixture, bis(triphenylphosphine)palladium (II) dichloride (141.8mg, 0.20mmol, 0.05equiv) and a solution of 2-amino-3,5-dibromopyrazine (1.02g, 4.03mmol, 1.0equiv) in dry THF (25mL) were added sequentially at room temperature. The resulting orange-colored reaction mixture was stirred for 3 days at room temperature and then quenched with water (50mL) at 0¡ãC. The mixture was diluted with ethyl acetate (300mL) and water (100mL). The organic layer was separated and the aqueous layer was extracted with ethyl acetate (4¡Á200mL). The combined organic layers were dried over anhydrous Na2SO4 and concentrated on a rotary evaporator. The residue was dissolved in CH2Cl2 and purified by silica gel column chromatography (gradient elution: PE?EtOAc, 85:15?65:35) to afford compound 11 (738.2mg, 2.79mmol, 70percent) as viscous yellow oil. Rf=0.46 (silica gel, PE?EtOAc, 7:3); 1H NMR (400MHz, CDCl3): delta=7.93 (s, 1H), 7.26?7.21 (m, 2H), 7.20?7.15 (m, 1H), 7.15?7.10 (m, 2H), 4.40 (br s, 2H), 3.99 (s, 2H); 13C NMR (100MHz, CDCl3): delta=152.3, 142.6, 141.9, 135.8, 129.2, 128.6, 127.4, 126.4, 40.9; IR (neat): numax=3472, 3314, 3200, 3060, 3027, 2919, 2850, 1605, 1555, 1529, 1494, 1424, 1389, 1340, 1261, 1220, 1158, 1117, 1073, 1048, 1028, 1002, 923, 905, 791, 759, 726, 696, 634cm?1; HRMS (ESI): calcd for C11H1179BrN3+ 264.0131; found 264.0133; calcd for C11H1181BrN3+ 266.1414; found 266.0113. The spectroscopic data are in good agreement with those reported in the literature.11d

The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.

Reference:
Article; Vece, Vito; Vuocolo, Giuseppina; Tetrahedron; vol. 71; 46; (2015); p. 8781 – 8785;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

As we all know, there are many different methods for the synthesis of a compound, and people can choose the synthesis method that suits their own laboratory according to the actual situation. 4858-85-9 name is 2,3-Dichloropyrazine, This compound is widely used in many fields, so it is necessary to find a new synthetic route. The downstream synthesis method of this compound is introduced below. 4858-85-9

2,3-Pyrazinedithiol (pdt) was synthesized according to a literature procedure [15,26-28]. 2,3-Dichloropyrazine (12.02g, 0.07668mol) was dissolved in 200mL MeOH under inert atmosphere. NaSH¡¤xH2O (23.49g, 0.2133mol) was dissolved in 100mL H2O under inert atmosphere. The solutions were combined, and the yellow reaction mixture was brought to reflux at 90C for 15h. 100mL of a 1.21M HCl (aq) solution was slowly added to the reaction mixture. The mixture slowly turned red, and some dark red precipitate was visible. The mixture was cooled to -20C for 3h, after which the precipitate (4.972g, 42.7%) was filtered and washed with cold MeOH. 1H NMR (CDCl3): 13.50ppm (2H), 6.85ppm (2H). IR (neat): nu/cm-1=3083, 2893, 1630, 1547, 1528, 1480, 1316, 1290, 1148, 1133, 1071, 1051, 852, 828, 820, 803, 726, 668, 623. Element. Anal. Calc. for H4C4N2S2: H, 2.80; C, 33.31; N, 19.42; S, 44.47. Found: H, 2.83; C, 32.92; N, 19.05; S, 44.23%.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 2,3-Dichloropyrazine, and friends who are interested can also refer to it.

Reference:
Article; Kennedy, Steven R.; Kozar, Morgan N.; Yennawar, Hemant P.; Lear, Benjamin J.; Polyhedron; vol. 103; (2016); p. 100 – 104;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

123-32-0, Researchers who often do experiments know that organic synthesis is a process of preparing more complex target molecules from simple raw materials through one or more chemical reactions. Generally, it requires fewer steps, and cheap raw materials. 123-32-0, name is 2,5-Dimethylpyrazine, A new synthetic method of this compound is introduced below.

In a 500-L reactor equipped with a reflux condenser, 250 kg of water and 20 kg of 2,5-dimethylpyrazine were added.Potassium permanganate 4.0kg, heated to 82C, kept at 80C for 1.6h, the solution purple faded and cooled to 76C,Then add 4.0kg of potassium permanganate, slowly warming to 82C, and hold at 82C for 1.6h.The solution purple faded and then incubated for 2.5 hours, and the temperature was reduced to 22 DEG C.; the filter cake was filtered, the filter cake was washed with 12 kg of water, and the filtrate was combined;The combined filtrate is first concentrated under normal pressure, distilled out of water and pyrazine solution (recovery application), after about 82% steaming,Diverted under reduced pressure to dryness; which distilled out of the filtrate 250kg, containing 2,5-dimethyl pyrazine 17kg;Add 15kg of water to the steamed kettle and raise the temperature to 52C to fully dissolve it; then pump it to a neutralization kettle., Adjust the pH to 2.5 with 1+1 sulfuric acid at about 6Kg, and extract with butanone (80Kg x 3) 3 times at 52 C to combine the organic phases;The organic phase was allowed to stand for 24 hours and a small amount of water was removed in the lower layer. The upper organic layer was degassed to dryness at atmospheric pressure.Add 10kg of water to heat and dissolve it, and while it is hot, the filtrate is cooled to 0C, crystallized, and suction filtered.The crude product was dried to 3.6kg; recrystallized from butanone to give 3.2kg of light yellow crystalline powder of 5-methylpyrazine-3-carboxylic acid.The yield was 81.6% and the purity was 99.4%.

The basis of chemical reaction formula synthesis, the synthesis route is composed of some specific reactions and combined according to certain logical thinking. We look forward to the emergence of more reaction modes in the future.

Reference:
Patent; Changzhou Engineering Polytechnic College; Chen Huiru; Chen Wenhua; Huang Yibo; Zhang Yuxiu; (7 pag.)CN108017586; (2018); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

These common heterocyclic compound, 5049-61-6, name is Pyrazin-2-amine, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. 5049-61-6

Ethyl bromopyruvate (2.153 g, 11.04 mmol) was added to a solution of 3-aminopyrazine (1 g, 10.51 mmol) in DME (10 mL) and the mixture was stirred continuously at 20-35 C. for 2 h. The reaction mixture was filtered and the solid which precipitated out was dried well, dissolved in EtOH (10 mL) and stirred under reflux for 2 h. This reaction mixture was then concentrated under reduced pressure to obtain a crude residue. The residue was diluted with aqueous sodium bicarbonate solution, and extracted with chloroform. The organic layer separated was washed with water and then with brine solution; dried over anhydrous sodium sulphate and concentrated under reduced pressure to afford the crude product. The crude product was further purified by column chromatography (using Silica gel 60-120 mesh and 60% EtOAc in Hexane as eluent) to afford 450 mg of the title compound the as a yellow solid.

Chemical properties determine the actual use. Each compound has specific chemical properties and uses. We look forward to more synthetic routes in the future to expand reaction routes of 5049-61-6.

Reference:
Patent; DR. REDDY’S LABORATORIES LTD.; Sasmal, Pradip Kumar; Ahmed, Shahadat; Prabhu, Ganesh; Tehim, Ashok; Paradkar, Vidyadhar; Dattatreya, Marahanakuli Prasanna; Mavinahalli, Nanjegowda Jagadeesh; US2015/5280; (2015); A1;,
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Pyrazine | C4H4N2 – PubChem

A common heterocyclic compound, 63744-22-9, name is 6,8-Dibromoimidazo[1,2-a]pyrazine, molecular formula is C6H3Br2N3, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route. 63744-22-9.

To 4-(4-(oxetan-3-yl)piperazin-l-yl)aniline II (2.00 g, 8.57 mmoles), Hunig’s base (3.29 mL) and 6,8-dibromoimidazo[l,2-a]pyrazine (2.37 g, 8.57 mmoles) was added in DMF (43 mL). The reaction was stirred at 85 C in a pressure tube for overnight. The material was quenched with saturated sodium bicarbonate, extracted with DCM (120 mL x 3) and the organic layers were combined and washed with water (120 mL x 3), dried over anhydrous sodium carbonate and concentrated. The crude material was purified using a 120 g Isco column and eluted off using a stepwise gradient of 0-60% (10% MeOH/DCM). The desired fractions were combined and concentrated to provide the title compound III.

The synthetic route of 6,8-Dibromoimidazo[1,2-a]pyrazine has been constantly updated, and we look forward to future research findings.

Reference:
Patent; GILEAD SCIENCES, INC.; DI PAOLO, Julie, A.; LIN, Joseph, Haw-Ling; LIN, Shao-Lee; (86 pag.)WO2016/172117; (2016); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

98-97-5, Adding a certain compound to certain chemical reactions, such as: 98-97-5, name is Pyrazine-2-carboxylic acid, belongs to Pyrazines compound, can increase the reaction rate and produce products with better performance than those obtained under traditional synthetic methods. Here is a downstream synthesis route of the compound 98-97-5.

(a) 2-pyrazine carboxylic acid, 104.3 gm, and 105.9 gm thionyl chloride were added to 800 ml methylene chloride and 5 ml dimethylformamide. The system was heated to reflux, at which point gas evolution took place. The system was stirred at reflux until gas evolution ceased, after about 5 hours, to give the 2-pyrazine carboxylic acid chloride. The solution was cooled to room temperature and transferred to a dropping funnel for use in Step (b) without further isolation.

According to the analysis of related databases, 98-97-5, the application of this compound in the production field has become more and more popular.

Reference:
Patent; Chevron Research Company; US4504484; (1985); A;; ; Patent; Chevron Research Company; US4588735; (1986); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem