Pyrazines

19838-07-4, name is 3-Methylpyrazin-2(1H)-one, belongs to pyrazines compound, is considered to be a conventional heterocyclic compound, which is widely used in drug synthesis. The chemical synthesis route is as follows. Quality Control of 3-Methylpyrazin-2(1H)-one

2-Hydroxy-3-methylpyrazine (14.94 g) was added to phosphorus oxychloride (55 mL) containing three drops of concentrated sulphuric acid and heated under reflux for one hour. The solution was allowed to cool to ambient temperature and then poured onto ice (600 g) and ether (300 mL). The mixture was stirred to effect hydrolysis of excess phosphorus oxychloride. Concentrated ammonia was added to adjust the pH of the mixture to 8, keeping the temperature below 10 C., the pH was then adjusted to 11 with sodium hydroxide (2M) and extracted with ether (3*300 mL). The combined organic extracts were dried (MgSO4). After removal of solvents, the residue was purified by MPLC (dichloromethane, silica) to give 2-chloro-3-methylpyrazine, (7.67 g). 1H NMR (DMSO-d6): delta2.6 (s, 3H), 8.4 (d, 1H, J=2 Hz), 8.55 (d, 1H, J=2 Hz). MS: 129 (M+H+)

The synthetic route of 19838-07-4 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Zeneca Limited; US5843942; (1998); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Application of 4774-14-5, 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. 4774-14-5, name is 2,6-Dichloropyrazine belongs to pyrazines compound, it is a common compound, a new synthetic route is introduced below.

2,6-Dichloropyrazine (2.89 g, 19.4 mmol) was stirred in aqueous NH3 (28%, 10 ml.) and heated to 100C in a sealed tube for 18 hours. The reaction mixture was cooled and the resultant precipitate was filtered. Trituration with water and then ether gave 6- chloropyrazin-2-amine as a white solid (2.28 g, 17.6 mmol, 91 % yield). 1H NMR (d6-DMSO, 400 MHz) ? 6.9 (brs, 2H), 7.70 (d, J = 0.4, 1 H), 7.80 (d, J = 0.4, 1 H); LC-MS (ZQ, 6 minutes) Rt = 1.05 minutes; m/z (ESI+) 130 (M+H).6-Chloropyrazin-2-amine (2.50 g, 19.3 mmol) was stirred in CH2CI2 (60 ml.) at 0C.A/-Bromosuccinimide (2.92 g, 16.4 mmol) was added slowly and the reaction mixture was stirred at 0C for 60 minutes. The reaction mixture was filtered through celite and concentrated to give a brown oil. Purification by flash chromatography, eluting with 0-25% EtOAc-hexanes, gave 5-bromo-6-chloropyrazin-2-amine as a yellow solid (1 .69 g, 8.16 mmol, 42% yield). 1H NMR (de-DMSO, 400 MHz) ? 7.1 (brs, 2H), 7.65 (s, 1 H); LC-MS (ZQ, 4 minutes) Rt = 1.46 minutes; m/z (ESI-) 205 (M-H).A mixture of 5-bromo-6-chloropyrazin-2-amine (1 .00 g, 4.8 mmol), copper (I) iodide (914 mg, 4.8 mmol), 18-crown-6 (95 mg, 0.36 mmol) andtetrakis(triphenylphosphine)palladium (0) (83 mg, 0.072 mmol) was suspended in dry DMF (20 ml.) and a stream of nitrogen was passed through for 5 minutes. Potassium cyanide (312 mg, 4.8 mmol) was added and the mixture was stirred at room temperature for 30 minutes, then refluxed at 200C for 3 hours. The mixture was cooled, diluted with EtOAc and absorbed onto silica gel (10 g). DMF was removed by evaporation. The product was purified by flash chromatography, eluting with 1 :1 EtOAc-hexanes, to yield 5- amino-3-chloropyrazine-2-carbonitrile as a yellow solid (607 mg, 3.93 mmol, 82% yield). 1H NMR (d6 DMSO, 400 MHz) ? 7.87 (s, 1 H), 8.1 (brs, 2H); LC-MS (ZQ, 4 minutes) Rt = 1.20 minutes; m/z (ESI-) 153 (M-H).

In the field of chemistry, the synthetic routes of compounds are constantly being developed and updated. I will also mention this compound in other articles, 2,6-Dichloropyrazine, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; CANCER RESEARCH TECHNOLOGY LIMITED; COLLINS, Ian; LAINCHBURY, Michael; MATTHEWS, Thomas Peter; READER, John Charles; WO2013/68755; (2013); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 1458-16-8, These common heterocyclic compound, 1458-16-8, name is Methyl 3-amino-6-iodopyrazine-2-carboxylate, 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.

30 ml of ammonia in water is added under magnetic stirring to 15 g (53.8 mmol) of a solution of methyl 3-amino-6-iodopyrazine-2-carboxylate in 150 ml of methanol. The reaction medium is stirred at 25C for 48 hours. After evaporation of the solvents, the precipitate obtained is filtered, rinsed with water and then dried at 50C to yield 12.50 g of 3-amino-6-iodopyrazine-2-carboxamide (88%) in the form of a beige solid.LCMS (EI, m/z): (M+l) 265.021H NMR: 6H ppm (400 MHz, DMSO): 8.35 (1H, s, CHarom), 7.85 (1H, bs, H), 7.60 (3H, bs, NH), 3.25 (3H, s, CH3)

The synthetic route of 1458-16-8 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; PIERRE FABRE MEDICAMENT; KALOUN, El Bachir; BEDJEGUELAL, Karim; RABOT, Remi; KRUCZYNSKI, Anna; SCHMITT, Philippe; PEREZ, Michel; RAHIER, Nicolas; WO2012/101239; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

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. 5521-58-4, name is 5-Methylpyrazin-2-amine belongs to pyrazines compound, it is a common compound, a new synthetic route is introduced below. COA of Formula: C5H7N3

A solution of HBr/CH3CO2H (360 g (260 mL), 1.50 mol, 33% HBr in CH3CO2H) in anhydrous CHCl3 (300 mL) was added over 15 min to a solution of 5-methylpyrazin-2-amine 15 (42 g, 0.38 mmol) in CHCl3 (1 L). The reaction flask was wrapped in aluminum foil and heated to 50 C for 30 min in the dark whereupon a solution of Br2 (68 g, 0.42 mmol) in CHCl3 (500 mL) was added dropwise over 3 h during which time the internal temperature of the reaction never exceeded 55 C. After 18 h at 55 C the solvent was evaporated under reduced pressure. The crude mixture was diluted with water (200 mL) and the pH was adjusted to pH=9 by the addition of solid Na2CO3. The suspension was filtered under vacuum and the filtrate was extracted with EtOAc (1 L×5). The combined organic extracts were concentrated under reduced pressure and purified by flash silica gel chromatography eluting with petroleum ether/EtOAc (5:1?1:1) to give compound 6-bromo-5-methylpyrazin-2-amine 17a (36 g, 50%) as a light orange solid; mp 154-157 C; IR (KBr): 3315, 3188, 1744, 1638, 1575, 1482, 1375, 1308, 1051 cm-1; 1H NMR (400 MHz, CDCl3): delta=7.84 (s, 1H), 4.55 (br s, 2H), 2.52 (s, 3H); 13C NMR (100 MHz, CDCl3): delta=152.2, 141.8, 138.4, 129.2, 22.2; HRMS-ESI: calcd for C5H7BrN3 (M+H)+: 187.9823 and 189.9803; found: 187.9816 and 189.9796. An analytical sample of 3-bromo-5-methylpyrazin-2-amine (17b) was also isolated for spectroscopic analysis; mp 56-57 C. 1H NMR (400 MHz, CDCl3): delta=7.80 (s, 1H), 4.95 (br s, 2H), 2.38 (s, 3H); 13C NMR (100 MHz, CDCl3): delta=150.6, 142.8, 139.9, 125.2, 19.7; HRMS-ESI: calcd for C5H7BrN3 (M+H)+: 187.9823 and 189.9803; found: 187.9817 and 189.9796.

The synthetic route of 5521-58-4 has been constantly updated, and we look forward to future research findings.

Reference:
Article; Harris, Anthony R.; Nason, Deane M.; Collantes, Elizabeth M.; Xu, Wenjian; Chi, Yushi; Wang, Zhihan; Zhang, Bingzhi; Zhang, Qingjian; Gray, David L.; Davoren, Jennifer E.; Tetrahedron; vol. 67; 47; (2011); p. 9063 – 9066;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Related Products of 33332-25-1, 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. 33332-25-1, name is Methyl 5-chloropyrazine-2-carboxylate, This compound has unique chemical properties. The synthetic route is as follows.

Example 35-Chloropyrazine-2-carboxylic acidFehler. Es ist nicht moglich, durch die Bearbeitung von Feldfunktionen Objekte zu erstellen. Methyl 5-chloropyrazine-2-carboxylate (CAS [33332-25-1], 1 g, 5.79 mmol) was dissolved in a mixture of THF (50 ml) and water (50 ml). Lithium hydroxide monohydrate (243 mg, 5.79 mmol) was added and the reaction mixture was stirred at RT overnight. The pH was adjusted to 1 with 1M HC1 and the product was extracted with three portions of EtOAc. The combined organic layers were dried over Na2S04 and concentrated under vacuum. The crude material was purified by flash chromatography (Si02, 50 g, 0 to 20% MeOH in DCM) to yield the title compound as white solid (741 mg, 81%). MS (ISP): m/z = 159.0 [M+H]+.

The chemical industry reduces the impact on the environment during synthesis Methyl 5-chloropyrazine-2-carboxylate. I believe this compound will play a more active role in future production and life.

Reference:
Patent; F. HOFFMANN-LA ROCHE AG; BORRONI, Edilio; GOBBI, Luca; HILPERT, Hans; HONER, Michael; MURI, Dieter; NARQUIZIAN, Robert; POLARA, Alessandra; WO2012/168175; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

In the chemical reaction process, reaction time, type of solvent, can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product. An updated downstream synthesis route of 486460-20-2 as follows. Safety of 3-(Trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine

The compound 4a (1g) (5.33 mmol) was hydrogenated at atmospheric pressure in ethanol (10 mL) using 10% Pd/C as catalyst (500 mg) at ambient temperature for 10 hour. The reaction mixture was filtered over celite and the celite bed was washed with 5 mL of ethanol and the filtrate was concentrated under reduced pressure. The obtained crude mass was passed through a small plug of silica using (5 to 8% of methanol in dichloromethane to give 0.9 g (87%) of the product as oil.

According to the analysis of related databases, 486460-20-2, the application of this compound in the production field has become more and more popular.

Reference:
Article; Nitlikar, Lakshmikant H.; Darandale, Sunil N.; Shinde, Devanand B.; Letters in Organic Chemistry; vol. 10; 5; (2013); p. 348 – 352;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Some common heterocyclic compound, 95-89-6, name is 3-Chloro-2,5-dimethylpyrazine, molecular formula is C6H7ClN2, 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. Formula: C6H7ClN2

1. 2-Iodo-3,6-dimethylpyrazine 2-Iodo-3,6-dimethylpyrazine was prepared from 2-chloro-3,6-dimethylpyrazine (Aldrich) by the procedure of Hirschberg et al, J. Org. Chem. (1961) 26, 1907.

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 95-89-6, its application will become more common.

Reference:
Patent; Merck Sharp & Dohme Limited; US5260293; (1993); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Electric Literature of 5521-58-4, In the chemical reaction process, reaction time, type of solvent, can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product. An updated downstream synthesis route of 5521-58-4 as follows.

Step 6: 5-Methoxy-4-[3-(5-methyl-pyrazin-2-yl)-ureido]-2-trifluoromethyl-benzoic acid methyl ester. To a stirred solution of 5-methoxy-4-(4-nitro-phenoxycarbonylamino)-2-trifluoromethyl-benzoic acid methyl ester (878 mg, 2.1 mmol) in 4.2 mL NMP at room temperature under nitrogen was added 2-amino-5-methylpyrazine (232 mg, 2.1 mmol) and the reaction heated to 85 C. After six hours the reaction was cooled to room temperature and a precipitate formed. The precipitate was triturated with EtOAc (25 mL) and the urea isolated by filtration as a tan solid (470 mg, 58%).

According to the analysis of related databases, 5521-58-4, the application of this compound in the production field has become more and more popular.

Reference:
Patent; Keegan, Kathleen S.; Kesicki, Edward A.; Gaudino, John Joseph; Cook, Adam Wade; Cowen, Scott Douglas; Burgess, Laurence Edward; US2003/69284; (2003); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Reference of 58138-79-7, 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. 58138-79-7 name is 2,6-Diiodopyrazine, 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.

STAGE 2: preparation of 2-iodo-6-methoxypyrazine 2,6-Diiodopyrazine (5.0 g, 15 mmol) was added to a solution of sodium methoxide in methanol (prepared from sodium (0.35 g, 15 mmol) and methanol (40 ml)) and the mixture was heated at reflux temperature for 1 hour. After cooling, the solution was diluted with water (200 ml) and extracted with diethylether (3*100 ml). The combined extracts were washed with water, dried over magnesium sulphate and concentrated under reduced pressure to give the product as a white solid (3.5 g, 100percent) m. pt. 35.7-37.2 NMR (90 MHz, CDCl3): b 8.40 (1H, s), 8.16 (1H,s), 3.98 (3H,s). m/z 236(M+), 127, 109 (100percent).

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 2,6-Diiodopyrazine, and friends who are interested can also refer to it.

Reference:
Patent; Imperial Chemical Industries, PLC; US4975112; (1990); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Adding a certain compound to certain chemical reactions, such as: 6863-73-6, name is 3-Chloropyrazin-2-amine, 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 6863-73-6, HPLC of Formula: C4H4ClN3

2-Amino-3-chloropyrazine 9 (10.0 g, 77.2 mmol) was added to a stirred suspension of NCS (11.6 g, 86.9 mmol) in chloroform (73 mL). The reaction mixture was heated at reflux for 4 h. The solution was cooled and partitioned between chloroform (180 mL) and water (2*50 mL). The organic layer was dried, filtered and concentrated. Flash chromatography on silica, eluting with chloroform, gave 10 (9.66 g, 76%) as a pale yellow solid. Mp 200-202 C; Rf (CHCl3) 0.32; numax (thin film/cm-1) 3411 (NH2), 3019 (Ar CH); (found: C, 28.89; H, 1.71; N, 24.99; C4H3N3Cl2: 0.125(H2O) requires C, 28.90; H, 1.97; N, 25.28%); deltaH (500 MHz; CDCl3) 4.96 (2H, br s, NH2), 7.90 (1H, s, 6-H); deltaC (125 MHz; CDCl3) 131.4, 134.6, 140.0, 150.3; GC-MS m/z 167, 165, 163 (M+), GC tR 2.51 min; purity 98%; HRMS (found: MH+ m/z 163.9782; requires 163.9777).

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:
Article; Caldwell, John J.; Veillard, Nicolas; Collins, Ian; Tetrahedron; vol. 68; 47; (2012); p. 9713 – 9728,16;; ; Article; Caldwell, John J.; Veillard, Nicolas; Collins, Ian; Tetrahedron; vol. 68; 47; (2012); p. 9713 – 9728;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem