Pyrazines

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. 13301-04-7, name is Methyl 3,6-dibromopyrazine-2-carboxylate, A new synthetic method of this compound is introduced below., 13301-04-7

Step 1: Synthesis of compound (B) as described in the general reaction scheme; 3,6-dibromo-pyrazine-2-carboxylic acid LiOH (655 mg, 27 mmol) is added to a solution of 3,6-dibromo-pyrazine-2-carboxylic acid methyl ester (A) (J. Med. Chem. 1969, 12, 285-87) (2.7 g, 9 mmol) in THF:water:MeOH (18:4.5:4.5 mL). The reaction is stirred at 5 C. for 30 min, concentrated in vacuo, taken up in DCM and washed with 1N HCl. The organic phase is dried over anhydrous MgSO4 and concentrated in vacuo to afford compound (B). 1H NMR (250 MHz, CDCl3) delta ppm 8.70 (s, 1H).

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; WIGERINCK, Piet Tom Bert Paul; ANDREWS, Martin James Inglis; De WEER, Marc Maurice Germain; SABOURAULT, Nicholas Luc; KLUGE, Stefan Christian; US2011/118269; (2011); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

63744-22-9, 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. 63744-22-9, name is 6,8-Dibromoimidazo[1,2-a]pyrazine belongs to Pyrazines compound, it is a common compound, a new synthetic route is introduced below.

To a stirred suspension of intermediate example 1-1 6,8-dibromo-imidazo[1,2-a]pyrazine (489 g, 1766 mmol) in MeOH (2900 mL) at -20 C. was dropwise added a solution of sodium methan thiolate (225 g, 3214 mmol, 1.8 eq) in 800 mL water. After stirring overnight, the clear solution was poured on 30 L water and the yellowish precipitate was filtered, washed with 3 L water and dried in vaccuo to yield 301 g 6-bromo-8-methylsulfanyl-imidazo[1,2-a]pyrazine (69.8%). 1H-NMR (300 MHz, d6-DMSO): delta=8.64 (1H, s), 8.00 (1H, d), 7.66 (1H, d2.54 (3H, s) ppm.

The synthetic route of 63744-22-9 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; BAYER INTELLECTUAL PROPERTY GMBH; Koppitz, Marcus; Klar, Ulrich; Jautelat, Rolf; Kosemund, Dirk; Bohlmann, Rolf; Bader, Benjamin; Lienau, Philip; Siemeister, Gerhard; US2013/281460; (2013); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

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. 767340-03-4, name is (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine, This compound has unique chemical properties. The synthetic route is as follows., 767340-03-4

Ligand Metal precursor percentyieldb percent eec config. 15 3 A [Rh(cod) 2]BF4 77 88 R 4 B [Rh(cod)Cl]2 58 76 R 5 C [Rh(cod)Cl]2 15 78 a: Reaction conditions: in TFE, 5 molpercent metal precursor, 5 molpercent ligand, 90 psig H2, 50 ¡ãC, 18 h; b: Assayed by HPLC; c: Assayed by chiral HPLC using a AS-RH chiral column eluting with 20percent acetonitrile/water as the mobile phase.

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; MERCK & CO., INC.; SOLVIAS AG; WO2005/97733; (2005); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

6164-79-0, Name is Methyl 2-pyrazinecarboxylate, 6164-79-0, 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.

d Pyrazine-2-hydrazide To a solution of the product from Example 1 step c) (22 g, 159 mmol) in methanol (250 ml) was slowly added hydrazine monhydrate (36.6 ml, 710 mmol). The reaction mixture was stirred for 1.5 h. The precipitate produced was filtered, washed with diethyl ether and dried in the oven at 80 C. to give the required product (30 g). 1H NMR (250 MHz, DMSO) delta 4.66 (2H, broad peak), 8.66 (1H, m), 8.84 (1H, d, J=2.5 Hz), 9.13 (1H, d, J=2.5 Hz), 10.15 (1H, broad peak); MS (ES+) m/e 139 [MH+].

Statistics shows that Methyl 2-pyrazinecarboxylate is playing an increasingly important role. we look forward to future research findings about 6164-79-0.

Reference:
Patent; Merck Sharp & Dohme Ltd.; US6297235; (2001); B1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

875781-43-4, A common heterocyclic compound, 875781-43-4, name is 2-Bromo-5H-pyrrolo[2,3-b]pyrazine, molecular formula is C6H4BrN3, 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.

Preparation of 2-bromo-7-iodo-5H-pyrr lo [3,2-6] yrazine (Intermediate AT)[0316] To a solution of 2-bromo-5H-pyrrolo[3,2-?]pyrazine [Intermediate AS] (0.68 g, 3.4 mmol) in acetone (17 mL) was added N-iodosuccinimide (0.82 g, 3.6 mmol) and the resulting mixture was stirred for 4 h at rt. The mixture was evaporated in vacuo to yield a residue that was purified via silica gel chromatography eluting with 40% THF in hexanes to give the title compound as a yellow solid (0.99 g, 89%). 1H NMR (DMSO-dtf, 300 MHz): delta 12.82 (s, 1H), 8.42 (s, 1 H), 8.20 (s, 1 H). HPLC retention time: 2.23 minutes. MS ESI (m/z): 324.0, 326.0 (M+H)+, calc. 323.

The synthetic route of 875781-43-4 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; UNIVERSITY OF ROCHESTER; GELBARD, Harris, A.; DEWHURST, Stephen; GOODFELLOW, Val, S.; WIEMANN, Torsten; RAVULA, Satheesh, Babu; LOWETH, Colin, J.; WO2011/149950; (2011); A2;,
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. 36070-80-1 name is 5-Chloropyrazine-2-carboxylic acid, 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. 36070-80-1

General procedure: The corresponding substituted salicylanilide 2 (1 mmol) and 5-chloropyrazine-2-carboxylic acid 1 (1 mmol) were dissolved in dryDMF (8 mL), the solution was cooled to 10 C and DCC (1.2 mmol)was added in three portions during 1 h. The mixture was stirred foradditional 3 h at the same temperature and then stored at 4 C for20 h. The precipitate of N,N0-dicyclohexylurea was removed byfiltration and the solvent was evaporated in vacuo till dryness. Thecrude products 3 were purified by one or repeated crystallizationfrom ethyl acetateehexane mixture.

At the same time, in my other blogs, there are other synthetic methods of this type of compound, 5-Chloropyrazine-2-carboxylic acid, and friends who are interested can also refer to it.

Reference:
Article; Baranyai, Zsuzsa; Kratky, Martin; Vin?ova, Jarmila; Szabo, Nora; Senoner, Zsuzsanna; Horvati, Kata; Stola?ikova, Ji?ina; David, Sandor; Bosze, Szilvia; European Journal of Medicinal Chemistry; vol. 101; (2015); p. 692 – 704;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

15707-23-0, 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 15707-23-0 as follows.

Ag2O (23.2 mg, 0.1 mmol), 3-nitro-1,2-benzenedicarboxylicacid (H2npt) (42.2 mg, 0.2 mmol) and epyz (24.4 mg, 0.2 mmol) were dissolved in methanol-H2O-DMF mixed solvent (6 mL,v/v/v = 1/1/1) in the presence of ammonia (0.5 mL, 14 M) underultrasonic treatment (160 W, 40 kHz, 30 min) under 40 C. Theresultant colorless solution was allowed slowly to evaporate atroom temperature in the dark. After several days, colorless platecrystals of 1 were isolated in about a 43% yield. They were washedwith a small volume of cold ethanol. Anal. Calc. for Ag2C15H13N3O6:C, 32.94; H, 2.40; N, 7.68. Found: C, 32.98; H, 2.38; N, 7.72%. IR(KBr): m (cm1) = 3440 (m), 3088 (w),3046 (w), 2976 (m),2932(w), 2876 (w), 1590 (s), 1520 (s), 1457(s), 1408 (s), 1344 (s),1288 (m), 1162 (m), 1027 (w), 929 (m), 859 (m), 824 (m), 782(w), 747 (w), 704 (m), 683 (m), 586 (w).

According to the analysis of related databases, 2-Ethyl-3-methylpyrazine, the application of this compound in the production field has become more and more popular.

Reference:
Article; Zhang, Ting; Wang, Dan-Feng; Huang, Rong-Bin; Zheng, Lan-Sun; Inorganica Chimica Acta; vol. 427; (2015); p. 299 – 304;,
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 63744-22-9 as follows. 63744-22-9

General procedure: 6,8-dibromoimidazo[1,2-a]pyrazine (6, 1.86 g, 6.72 mmol) was added to asolution of 3a-3c, 5a-5e (5.6 mmol), DIPEA (1.4 mL, 8.4 mmol) inisopropanol (60 mL), stirred at 85 C for 8 h, and then the solvent wasevaporated to dryness. The crude product was purified by columnchromatography to obtain the desired intermediates 7a, 11a-11 g.

According to the analysis of related databases, 63744-22-9, the application of this compound in the production field has become more and more popular.

Reference:
Article; Fan, Yan; Huang, Zhi; Li, Yao; Qin, Zhongxiang; Wang, Cheng; Wang, Tianqi; Wang, Xin; Xiang, Rong; Yang, Shengyong; Bioorganic Chemistry; vol. 95; (2020);,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

767340-03-4, name is (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine, 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. 767340-03-4

Into a 500 ml flask were charged chloro(l,5-cyclooctadiene)rhodium(I) dimer {[Rh(cod)Cl]2}(292 mg, 1.18 mmol) and (R,S) f-butyl Josiphos (708 mg, 1.3 mmol) under a nitrogen atmosphere. Degassed MeOH was then added (200 mL) and the mixture was stirred at room temperature for 1 h. Into a 4 L hydrogenator was charged the enamine amide 2Lambda (118 g, 0.29 mol) along with MeOH (1 L). The slurry was degassed. The catalyst solution was then transferred to the hydrogenator under nitrogen. After degassing three times, the enamine amide was hydrogenated under 200 psi hydrogen gas at 50 0C for 13 h. Assay yield was determined by EtaPLC to be 93% and optical purity to be 94% ee.The optical purity was further enhanced in the following manner. The methanol solution from the hydrogenation reaction (18 g in 180 mL MeOH) was concentrated and switched to methyl t- butyl ether (MTBE) (45 mL). Into this solution was added aqueous Eta3PO4 solution (0.5 M, 95 mL).After separation of the layers, 3NNaOH (35 mL) was added to the water layer, which was then extracted with MTBE (180 mL + 100 mL). The MTBE solution was concentrated and solvent switched to hot toluene (180 mL, about 75 0C). The hot toluene solution was then allowed to cool to 0 0C slowly (5 – 10 h). The crystals were isolated by filtration (13 g, yield 72%, 98 – 99% ee); m.p. 114.1 – 115.7 0C. lH NMR (300 MHz, CD3CN): delta 7.26 (m), 7.08 (m), 4.90 (s), 4.89 (s), 4.14 (m), 3.95 (m), 3.40 (m), 2.68(m), 2.49 (m), 1.40 (bs).Compound 2-5 exists as amide bond rotamers. Unless indicated, the major and minor rotamers are grouped together since the carbon-13 signals are not well resolved: 13c NMR (CD3CN): delta 171.8, 157.4 (ddd , JCF = 242.4, 9.2, 2.5 Hz), 152.2 (major), 151.8 (minor), 149.3(ddd; JCF = 246.7, 14.2, 12.9 Hz), 147.4 (ddd, JCF = 241.2, 12.3, 3.7 Hz), 144.2 (q, JCF = 38.8 Hz), 124.6 (ddd , JCF = 18.5, 5.9, 4.0 Hz), 120.4 (dd , JCF = 19.1, 6.2 Hz), 119.8 (q, JCF = 268.9 Hz), 106.2 (dd , JCF = 29.5, 20.9 Hz), 50.1, 44.8, 44.3 (minor), 43.2 (minor), 42.4, 41.6 (minor), 41.4, 39.6, 38.5 (minor), 36.9. The crystalline free base 2^ can also be isolated as follows:(a) The reaction mixture upon completion of the hydrogenation step is charged with 25 wt% of Ecosorb C-941. The mixture is stirred under nitrogen for one h and then filtered. The cake is washed with 2L/kg of methanol. Recovery of free base is about 95% and optical purity about 95% ee.(b) The freebase solution in methanol is concentrated to 3.5-4.0 L/kg volume (based on free base charge) and then solvent-switched into isopropanol (IPA) to final volume of 3.0 L/kg IPA.(c) The slurry is heated to 40 0C and aged 1 h at 4O0C and then cooled to 25 0C over 2 h. EPO (d) Heptane (7L/kg) is charged over 7 h and the slurry stirred for 12 h at 22-250C. The supernatant concentration before filtering is 10-12 mg/g.(e) The slurry is filtered and the solid washed with 30% IPA/heptane (2L/kg).(f) The solid is dried in a vacuum oven at 40 0C. (g) The optical purity of the free base is about 99% ee.

Statistics shows that 767340-03-4 is playing an increasingly important role. we look forward to future research findings about (2Z)-4-Oxo-4-[3-(trifluoromethyl)-5,6-dihydro[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-yl]-1-(2,4,5-trifluorophenyl)but-2-en-2-amine.

Reference:
Patent; MERCK & CO., INC.; WO2006/33848; (2006); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

1458-18-0, A common compound: 1458-18-0, name is Methyl 3-amino-5,6-dichloropyrazine-2-carboxylate, belongs to Pyrazines compound, it can change the direction of chemical reaction, and react with certain compounds to generate new functional products. A new synthetic method of this compound is introduced below.

S-Amino–chloro-S-methoxy-pyrazine-?-carboxylic acid methyl ester [00442]Methyl 3-amino-5,6-dichloropytauazinoate (1.1 g, 5 mmol) was dissolved in 200 mL of boiling anhydrous methanol containing metallic sodium (115 mg, 5 mmol). The product which separates on cooling, is filtered, washed with water and methanol and dried to give 1.Og (92%) of methyl S-amino-S-methoxy–chloro-pyrazinoate which was recrystallized from acetonitrile. MP. 255-257 C. [00443J 1H NMR (DMSO-rf?, 400MHz): delta 7.61 Qm, 2H, NH2, exchangeable with D2O), 3.97 (s, 3H), 3.80 (s, 3H).

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, Methyl 3-amino-5,6-dichloropyrazine-2-carboxylate, other downstream synthetic routes, hurry up and to see.

Reference:
Patent; ARDEA BIOSCIENCES INC.; WO2009/89263; (2009); A2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem