Pyrazines

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

Step 1: 2-Bromo-5H-pyrrolo[2,3-b]pyrazine (1.98 g, 10.0 mmol) was dissolved in DMF (33 mL) and cooled down to 0 C. NaH (60%, 0.480 g, 12.0 mmol) was added slowly. After the addition was complete stirring was continued for 30 minutes at 0 C. (2-Chloromethoxy-ethyl)-trimethyl-silane (2.1 mL, 12.0 mmol) was added and the reaction mixture was allowed to warm up overnight. The reaction was quenched with H2O. The aqueous layer was extracted with EtOAc. The organic layer was dried (MgSO4), filtered, concentrated, and purified by SiO2 chromatography (150 g SiO2, hexanes/EtOAc 0-35% EtOAc) to give 2.81 g of 2-bromo-5-(2-trimethylsilanyl-ethoxymethyl)-5H-pyrrolo[2,3-b]pyrazine as a yellow liquid (86% yield).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 875781-43-4, its application will become more common.

Reference:
Patent; Bamberg, Joe Timothy; Hermann, Johannes Cornellius; Lemoine, Remy; Soth, Michael; US2010/144745; (2010); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

19745-07-4, 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 19745-07-4 as follows.

A mixture of A-63 (10.00 g, 67.12 mmol) in EtOH (80 mL) was stirred under N2 at 80 C for 16 hours. The mixture was concentrated to give the crude product, which was triturated from H20 (20 mL) to give A-64 (1.60 g, 11.07 mmol) as a solid. 1H NMR (400MHz, CDCI3) _ = 8.10 – 8.01 (m, 2H), 6.03 (br s, 1H), 3.85 (br s, 2H).

According to the analysis of related databases, 2,5-Dichloropyrazine, the application of this compound in the production field has become more and more popular.

Reference:
Patent; PRAXIS PRECISION MEDICINES, INC.; REDDY, Kiran; MARTINEZ BOTELLA, Gabriel; GRIFFIN, Andrew, Mark; MARRON, Brian, Edward; (364 pag.)WO2018/98499; (2018); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

55557-52-3, A common heterocyclic compound, 55557-52-3, name is 3-Chloropyrazine-2-carbonitrile, molecular formula is C5H2ClN3, 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.

Step-1: (0930) Preparation of (3-chloropyrazin-2-yl)methanamine hydrochloride: (0931) [00352] To a solution of 3-chloropyrazine-2-carbonitrile (10 g) in acetic acid (100 mL) was added Raney Nickel (50% slurry in water, 10 g). The resulting mixture was stirred under 4 bar hydrogen pressure at room temperature for 15 h. The reaction mixture was filtered through celite and the filtrate was concentrated under reduced pressure and co-evaporated with toluene. The remaining brown solid was dissolved in ethyl acetate at 50 C and cooled on an ice-bath. 4M hydrochloric acid in dioxane (50 mL) was added and the reaction mixture was allowed to stir at room temperature for 18 h. The precipitate formed was collected by filtration, washed with diethyl ether and dried under reduced pressure. The product brown solid obtained was dissolved in methanol at 60 C and filtered. The filtrate was partially concentrated, cooled to room temperature and diethyl ether (500 mL) was added. The mixture was allowed to stir at room temperature 18 h. The solids formed were collected by filtration, washed with diethyl ether and dried under reduced pressure to afford the title compound (3-chloropyrazin-2- yl)methanamine hydrochloride (7.67 g, crude) as a brown solid. Calculated (M+H): 144.03; Found (M+H): 144.0

The synthetic route of 55557-52-3 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; LUC THERAPEUTICS; ANDERSON, David, R.; VOLKMANN, Robert, A.; MENNITE, Frank, S.; FANGER, Christopher; (390 pag.)WO2017/100591; (2017); 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. 1458-18-0, name is Methyl 3-amino-5,6-dichloropyrazine-2-carboxylate, This compound has unique chemical properties. The synthetic route is as follows., 1458-18-0

The pyrazine (24.8 gm, 9.66 X 10″2 moles) was stirred in pyridine (200 mL) as benzoyl chloride (33.9 gm, 0.241 moles) was added in 3 portions. This solution was stirred at 65C overnight. After cooling, the pyridine was removed under reduced pressure and the remaining material was dissolved in methylene chloride (400 mL) and water (200 mL) was added. To this mixture was added potassium carbonate until the aqueous was basic to litmus. The methylene chloride solution was isolated and washed with 2% HCl (250 mL.). The solution was then dried over magnesium sulfate. After filtration, the solvents were removed under reduced pressure. The remaining material was stirred with diethyl ether (200 mL) causing the product to crystallize. The solid product was isolated by filtration. After washing with diethyl ether and drying the imide was obtained as a grey solid in a yield of 36.8 gm (82%).

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Reference:
Patent; JANUS BIOTHERAPEUTICS, INC.; LIPFORD, Grayson, B.; ZEPP, Charles, M.; WO2012/167046; (2012); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

33332-25-1, These common heterocyclic compound, 33332-25-1, name is Methyl 5-chloropyrazine-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.

a) 5-(3,3-Difluoro-azetidin-l-yl)-pyrazine-2-carboxylic acid methyl ester 5-Chloro-pyrazine-2-carboxylic acid methyl ester (CAN 33332-25-1; 15 g, 86.92 mmol) was dissolved in dioxane (100 mL). To this solution was added 3,3-difluoroazetidine hydrochloride (CAN 288315-03-7; 13.51 g, 104.31 mmol), and triethyl amine (31.3 mL, 226 mmol). The mixture was stirred 22 hours at 45 C and afterwards cooled to room temperature. Brine solution (100 mL) was added and the mixture was extracted with ethyl acetate. The organic phases were washed successively with sodium bicarbonate solution (10%, 300 mL) and brine (200 mL); dried with Na2S04 and filtered and concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, 200g, 30% to 50% ethyl acetate in hexane) to give the desired product (15 g, 75.3%) as white solid; LC- MS (UV peak area, ESI) 98.6%, 230.4 (M+H).

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 33332-25-1.

Reference:
Patent; F. HOFFMANN-LA ROCHE AG; BISSANTZ, Caterina; DHURWASULU, Baledi; GRETHER, Uwe; HAZRA, Anindya; HEBEISEN, Paul; ROEVER, Stephan; ROGERS-EVANS, Mark; WO2013/60751; (2013); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

767340-03-4, These common heterocyclic compound, 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, 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.

Into a 500 ML flask were charged chloro (1, 5-CYCLOOCTADIENE) rhodium (I) dimer { [Rh (cod) Cl] 2} (292 mg, 1.18 MMOL) and (R, S) t-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 2-4 (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 C for 13 h. Assay yield was determined by HPLC 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 H3PO4 solution (0.5 M, 95 mL). After separation of the layers, 3N NAOH (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 C). The hot toluene solution was then allowed to cool to 0 C slowly (5-10 h). The crystals were isolated by filtration (13 g, yield 72%, 98-99% ee); m. p. 114.1-115. 7 C. 1H NMR (300 MHz, CD3CN): 8 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) : 8 171. 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 2-5 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 C and aged 1 h at 40C and then cooled to 25 C over 2 h. (d) Heptane (7L/kg) is charged over 7 h and the slurry stirred for 12 h at 22-25C. 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 C. (g) The optical purity of the free base is about 99% ee.

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 767340-03-4.

Reference:
Patent; MERCK & CO., INC.; WO2005/20920; (2005); A2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

6863-73-6,Some common heterocyclic compound, 6863-73-6, name is 3-Chloropyrazin-2-amine, molecular formula is C4H4ClN3, 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.

A mixture of 25 (5.20 g, 40.1 mmol) and CuSO4 (640 mg, 4.01 mmol) in 12 M methanamine aqueous solution (40.0 mL, 480 mmol) was stirred at 120 C for 3 h under microwave irradiation. The reaction mixture was allowed to cool to room temperature and concentrated in vacuo. The residue was purified by flash column chromatography (silica gel, 0-5% MeOH in CHCl3) to give 26 (3.99 g, 80%) as a yellow solid. 1H NMR (DMSO-d6) delta 2.81 (d, 3H, J = 4.7 Hz), 5.84 (s, 2H), 6.13 (q, 1H, J = 4.7 Hz), 7.09 (d, 1H, J = 3.1 Hz), 7.23 (d, 1H, J = 3.1 Hz); MS (ESI) m/z 125 [M+H]+.

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route 3-Chloropyrazin-2-amine, its application will become more common.

Reference:
Article; Chino, Ayaka; Masuda, Naoyuki; Amano, Yasushi; Honbou, Kazuya; Mihara, Takuma; Yamazaki, Mayako; Tomishima, Masaki; Bioorganic and Medicinal Chemistry; vol. 22; 13; (2014); p. 3515 – 3526;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

486460-20-2, The chemical industry reduces the impact on the environment during synthesis 486460-20-2, name is 3-(Trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine, I believe this compound will play a more active role in future production and life.

3-(Trifluoromethyl)-l,2,4-triazolo[4,3-a] pyrazine (540 mg, 2.87 mmol, from Step A)was hydrogenated under atmospheric hydrogen with 10% Pd/C (200 mg) as a catalyst in ethanol (10 mL)at ambient temperature for 18 h. Filtration through Celite followed by concentration gave a dark coloredoil. Dichloromethane was added to the above oil and the insoluble black precipitate was filtered off.Concentration of the filtrate gave the title compound as an oil.’H NMR (500 MHz, CDC13) 5 2.21 (br, 1H), 3.29 (t, 2H, J = 5.5 Hz), 4.09 (t, 2H, J = 5.5 Hz), 4.24 (s,2H); LC-MS 193 (M+l).

The chemical industry reduces the impact on the environment during synthesis 3-(Trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine. I believe this compound will play a more active role in future production and life.

Reference:
Patent; MERCK & CO., INC.; WO2006/23750; (2006); A2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

33332-25-1, Adding some certain compound to certain chemical reactions, such as: 33332-25-1, name is Methyl 5-chloropyrazine-2-carboxylate, 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 33332-25-1.

Production Example 195- [2- (4-hydrazinocarbonylmethylphenyl) ethyl] pyrazine-2- carboxamide dihydrochloride step 1[0129] Ammonium chloride (558 mg, 10.4 iranol) was suspended in benzene (5 ml) and 2M-trimethylaluminum toluene solution (5.2 ml, 10.4 mmol) was added dropwise at 0C. After stirring for 1 hr, a solution of methyl 5-chloropyrazine-2-carboxylate (600 mg, 3.48 mmol) in benzene (5 ml) was added. The reaction mixture was heated to 50C, and stirred overnight. After cooling, the reaction mixture was poured into water, and neutralized with saturated aqueous sodium hydrogen carbonate solution. The mixture was extracted with ethyl acetate, and the organic layer was washed with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (dichloromethane:methanol = 100:0 -> 98:2) to give 5-chloropyrazine-2-carboxamide (236 mg, yield 43%) as a white 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 33332-25-1.

Reference:
Patent; R-tech Ueno, Ltd.; WO2009/145360; (2009); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

38557-72-1, A common heterocyclic compound, 38557-72-1, name is 2-Chloro-3,5-dimethylpyrazine, molecular formula is C6H7ClN2, 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.

To a mixture of 2-chloro-3,5-dimethylpyrazine (2.8 g), 1-Boc-piperazine (3.7 g), palladium (II) acetate (225 mg), 2-(dicyclohexylphosphino)-2′,4′,6′-tri-isopropyl-1,1′-biphenyl (953 mg) and sodium tert-butoxide (2.7 g) was added toluene (40 mL), and the mixture was refluxed for 8 hr. After cooling, the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, and the solvent was evaporated. The residue was purified by column chromatography (hexane:ethyl acetate) to give 3′,5′-dimethyl-2,3,5,6-tetrahydro[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester (5 g). 3′,5′-Dimethyl-2,3,5,6-tetrahydro[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester (5 g) was dissolved in chloroform (15 mL), 4N hydrogen chloride/ethyl acetate (15 mL) was added, and the mixture was stirred at room temperature overnight. Ethyl acetate (100 mL) was added, and the mixture was filtered to give the title compound (3.3 g).

The synthetic route of 38557-72-1 has been constantly updated, and we look forward to future research findings.

Reference:
Patent; Mitsubishi Tanabe Pharma Corporation; EP2364975; (2011); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem