Tag: M.W=100-200

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. 123-32-0 name is 2,5-Dimethylpyrazine, 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. 123-32-0

54 g (498 mmol) of 2,5-dimethylpyrazine (manufactured by Tokyo Chemical Industry Co., Ltd.) and 224 g (2.02 mol) of selenium dioxide were added to 840 ml of a mixed solution of pyridine and water (mixing mass ratio: 20/1) And the mixture was heated under reflux for 48 hours. The reaction solution was cooled to ambient temperature and filtered, and the filtration residue was washed with a mixed solution of pyridine and water (mixing mass ratio: 20/1), the filtrate and the washing solution were combined and the liquid was distilled off to obtain a solid It was.The resulting solid was dispersed in 2 M dimethylamine aqueous solution used as an extraction solvent, and residual solids were removed from the extract by filtration. By distilling off the solvent from the extract, 71 g (yield 85%) of 2,5-pyrazinedicarboxylic acid (3) was obtained.

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

Reference:
Patent; IHI Corporation; Waseda University; Sato, Yutaka; Kanomata, Norihiro; Yuchi, Takeshi; (19 pag.)JP2018/140981; (2018); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

6164-79-0, These common heterocyclic compound, 6164-79-0, name is Methyl 2-pyrazinecarboxylate, 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.

Method 54; Pvrazine-2-carboxaldehyde oxime A IN solution of lithium aluminium hydride in THF (73. 8ml, 73.8mmol) was added to a suspension of methyl pyrazine-2-carboxylate (20g, 145mmol) in anhydrous THF (300. 0ml) at-78¡ãC keeping the reaction temperature below-72¡ãC. On completion of addition the reaction mixture was left to stir at-78¡ãC for a further 20 minutes and then quenched with glacial acetic acid (20. 0ml). The resulting mixture was warmed to room temperature and the volatiles removed by evaporation. The residue was dissolved in 3N hydrochloric acid (116ml) and extracted with DCM. The extracts were combined, washed with saturated aqueous sodium hydrogen carbonate solution and the solvent evaporated. The residue was purified by chromatography on silica gel eluting with DCM/diethylether (100: 0 then 80: 20 and then 0: 100) to give pyrazine-2-carboxaldehyde (15.67g, 100percent). This was immediately dissolved in chloroform (200ml) cooled to 0¡ãC and hydroxylamine mono-hydrochloride (11. 02g, 159. 5mmol) and triethylamine (24. 2ml, 117. 4mmol) were added. The reaction mixture was then stirred at ambient temperature for 0.5 hour, and the solvent removed by evaporation. The residue suspended in diethylether (500ml) and the insolubles removed by filtration. The filtrate was evaporated and the residue purified by chromatography eluting with DCM/diethylether (100: 0 then 80: 20 and then 0: 100) to give the title compound (5. 5g, 31percent) as a solid. NMR (DMSO-d6) : 8.15 (s, 1H), 8.62 (dd, 2H), 8. 99 (s, 1H).

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 6164-79-0.

Reference:
Patent; ASTRAZENECA AB; ASTRAZENECA UK LIMITED; WO2005/40159; (2005); 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 274-79-3 as follows. 274-79-3

To a solution of imidazo[1,2-a]pyrazine (intermediate C) (2.8 g, 23.5 mmol) in AcOH (acetic acid) (200 ml) was added bromine (6 ml, 5 eq.) via addition funnel, with the reaction flask protected from light. After addition, the flask was sealed. The mixture was stirred at rt for 24 hr., 6 ml (5 eq.) of additional Br2 was added to the reaction mixture, which was further stirred at rt for 48 hr. The mixture was evaporated to remove Br2 and acetic acid, and the residue was dissolved in 10% IPA/DCM, washed with sat. Na2CO3 (300 ml). The organics were combined, dried and concentrated to afford 5.9 g (yield 97%) of 3,5-dibromo-imidazo[1,2-a]pyrazine. 1H-NMR (400 MHz, DMSO-d6) delta 9.05 (s, 1H), 8.09 (s, 1H), 7.99 (s, 1H). MS m/z 278 [M++1].

According to the analysis of related databases, 274-79-3, the application of this compound in the production field has become more and more popular.

Reference:
Patent; Sugen, Inc.; US2004/220189; (2004); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

These common heterocyclic compound, 55557-52-3, name is 3-Chloropyrazine-2-carbonitrile, 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. 55557-52-3

1-[3-(3-Chloro-phenyl)-acryloyl]-piperazine-2-carboxylic acid methyl ester (1.6 g, 5.18 mmol) was mixed with 3-chloro-pyrazine-2-carbonitrile (0.868 g, 6.22 mmol) and triethylamine (1.05 g, 10.36 mmol) in acetonitrile at 90 C. overnight. The reaction mixture was quenched water and extracted with dichloromethane. The product was purified by column chromatography with 50% ethyl acetate in hexanes to give 4-[3-(3-chloro-phenyl)-acryloyl]-3′-cyano-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl-3-carboxylic acid methyl ester (white solid, 1.5 g, 70.3%).

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 55557-52-3.

Reference:
Patent; AstraZeneca AB; NPS PHARMACEUTICALS; US2007/49578; (2007); A1;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

875781-43-4, 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. 875781-43-4, name is 2-Bromo-5H-pyrrolo[2,3-b]pyrazine, This compound has unique chemical properties. The synthetic route is as follows.

Step 5: Synthesis of 2-Bromo-7-iodo-5-(toluene-4-suIfonyl)-5H-pyrroIo[2,3-b]pyrazine.[0286] To a suspension of 2-Bromo-7-iodo-5H-pyrrolo[2,3-b]pyrazine (290 mg, 0.895mmol) in THF (5 ml) was added NaH (60%, 43 mg, 1.08 mmol) in one portion at 0 C.The resulting mixture was stirred for 20 minutes before a ‘solution of para-toluenesulfonylchloride (188mg, 0.98 mmol) in THF (2 mL) was added. The reaction mixture was thenstirred at room temperature for 3 hours. Solvents were removed and the resulting darkbrown residue washed with aqueous KOH, water and dried to afford the title compound(423 mg, 99% yield) as a light brown solid. .H-NMR (500 MHz, Patent; SGX PHARMACEUTICALS, INC.; WO2006/15124; (2006); A2;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

33332-29-5, 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 33332-29-5 as follows.

Step 2: 2,5-Dichloropyrazine; 5-Chloro-2-pyrazinamine (product of E1, step 1) (2.41g, 18.6mmole) was dissolved in concentrated hydrochloric acid (24ml), cooled in an ice-acetone bath and treated with a solution of sodium nitrite (2.63g, 38.1 mmole) in water (1 8ml) dropwise over a period of 1 hour. The mixture was cooled in an ice-water bath and left to stir for 1 hour. The mixture was allowed to warm to room temperature over 1 hour, neutralised by addition of sodium hydroxide solution (2M) and extracted with dichloromethane ( x 4). The dichloromethane layers were combined, dried under magnesium sulfate and evaporated in vacuo. The resulting residue was purified by column chromatography (1: 9 ethyl acetate: pentane) to afford the title compound (0.33g). ?H NMR (CDCl3) 8.40 (2H, s).

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

Reference:
Patent; GLAXO GROUP LIMITED; WO2005/97778; (2005); A1;,
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

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

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

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